foundationdb/fdbserver/ClusterController.actor.cpp

/*
 * ClusterController.actor.cpp
 *
 * This source file is part of the FoundationDB open source project
 *
 * Copyright 2013-2019 Apple Inc. and the FoundationDB project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <algorithm>
#include <iterator>
#include <map>
#include <memory>
#include <set>
#include <vector>

#include "fdbclient/SystemData.h"
#include "fdbrpc/FailureMonitor.h"
#include "fdbserver/EncryptKeyProxyInterface.h"
#include "flow/ActorCollection.h"
#include "fdbclient/ClusterConnectionMemoryRecord.h"
#include "fdbclient/NativeAPI.actor.h"
#include "fdbserver/ApplyMetadataMutation.h"
#include "fdbserver/BackupInterface.h"
#include "fdbserver/BackupProgress.actor.h"
#include "fdbserver/ConfigBroadcaster.h"
#include "fdbserver/CoordinatedState.h"
#include "fdbserver/CoordinationInterface.h" // copy constructors for ServerCoordinators class
#include "fdbserver/ClusterController.actor.h"
#include "fdbserver/ClusterRecovery.actor.h"
#include "fdbserver/DataDistributorInterface.h"
#include "fdbserver/DBCoreState.h"
#include "fdbserver/ConfigBroadcaster.h"
#include "fdbserver/MoveKeys.actor.h"
#include "fdbserver/LeaderElection.h"
#include "fdbserver/LogSystem.h"
#include "fdbserver/LogSystemConfig.h"
#include "fdbserver/LogSystemDiskQueueAdapter.h"
#include "fdbserver/WaitFailure.h"
#include "fdbserver/RatekeeperInterface.h"
#include "fdbserver/BlobManagerInterface.h"
#include "fdbserver/ServerDBInfo.h"
#include "fdbserver/Status.h"
#include "fdbserver/LatencyBandConfig.h"
#include "fdbclient/GlobalConfig.actor.h"
#include "fdbserver/RecoveryState.h"
#include "fdbclient/ReadYourWrites.h"
#include "fdbrpc/Replication.h"
#include "fdbrpc/ReplicationUtils.h"
#include "fdbrpc/sim_validation.h"
#include "fdbclient/KeyBackedTypes.h"
#include "flow/Trace.h"
#include "flow/Util.h"
#include "flow/actorcompiler.h" // This must be the last #include.

void failAfter(Future<Void> trigger, Endpoint e);

// This is used to artificially amplify the used count for processes
// occupied by non-singletons. This ultimately makes it less desirable
// for singletons to use those processes as well. This constant should
// be increased if we ever have more than 100 singletons (unlikely).
static const int PID_USED_AMP_FOR_NON_SINGLETON = 100;

// Wrapper for singleton interfaces
template <class Interface>
struct Singleton {
	const Optional<Interface>& interface;

	Singleton(const Optional<Interface>& interface) : interface(interface) {}

	virtual Role getRole() const = 0;
	virtual ProcessClass::ClusterRole getClusterRole() const = 0;

	virtual void setInterfaceToDbInfo(ClusterControllerData* cc) const = 0;
	virtual void halt(ClusterControllerData* cc, Optional<Standalone<StringRef>> pid) const = 0;
	virtual void recruit(ClusterControllerData* cc) const = 0;
};

struct RatekeeperSingleton : Singleton<RatekeeperInterface> {

	RatekeeperSingleton(const Optional<RatekeeperInterface>& interface) : Singleton(interface) {}

	Role getRole() const { return Role::RATEKEEPER; }
	ProcessClass::ClusterRole getClusterRole() const { return ProcessClass::Ratekeeper; }

	void setInterfaceToDbInfo(ClusterControllerData* cc) const {
		if (interface.present()) {
			TraceEvent("CCRK_SetInf", cc->id).detail("Id", interface.get().id());
			cc->db.setRatekeeper(interface.get());
		}
	}
	void halt(ClusterControllerData* cc, Optional<Standalone<StringRef>> pid) const {
		if (interface.present()) {
			cc->id_worker[pid].haltRatekeeper =
			    brokenPromiseToNever(interface.get().haltRatekeeper.getReply(HaltRatekeeperRequest(cc->id)));
		}
	}
	void recruit(ClusterControllerData* cc) const {
		cc->lastRecruitTime = now();
		cc->recruitRatekeeper.set(true);
	}
};

struct DataDistributorSingleton : Singleton<DataDistributorInterface> {

	DataDistributorSingleton(const Optional<DataDistributorInterface>& interface) : Singleton(interface) {}

	Role getRole() const { return Role::DATA_DISTRIBUTOR; }
	ProcessClass::ClusterRole getClusterRole() const { return ProcessClass::DataDistributor; }

	void setInterfaceToDbInfo(ClusterControllerData* cc) const {
		if (interface.present()) {
			TraceEvent("CCDD_SetInf", cc->id).detail("Id", interface.get().id());
			cc->db.setDistributor(interface.get());
		}
	}
	void halt(ClusterControllerData* cc, Optional<Standalone<StringRef>> pid) const {
		if (interface.present()) {
			cc->id_worker[pid].haltDistributor =
			    brokenPromiseToNever(interface.get().haltDataDistributor.getReply(HaltDataDistributorRequest(cc->id)));
		}
	}
	void recruit(ClusterControllerData* cc) const {
		cc->lastRecruitTime = now();
		cc->recruitDistributor.set(true);
	}
};

struct BlobManagerSingleton : Singleton<BlobManagerInterface> {

	BlobManagerSingleton(const Optional<BlobManagerInterface>& interface) : Singleton(interface) {}

	Role getRole() const { return Role::BLOB_MANAGER; }
	ProcessClass::ClusterRole getClusterRole() const { return ProcessClass::BlobManager; }

	void setInterfaceToDbInfo(ClusterControllerData* cc) const {
		if (interface.present()) {
			TraceEvent("CCBM_SetInf", cc->id).detail("Id", interface.get().id());
			cc->db.setBlobManager(interface.get());
		}
	}
	void halt(ClusterControllerData* cc, Optional<Standalone<StringRef>> pid) const {
		if (interface.present()) {
			cc->id_worker[pid].haltBlobManager =
			    brokenPromiseToNever(interface.get().haltBlobManager.getReply(HaltBlobManagerRequest(cc->id)));
		}
	}
	void recruit(ClusterControllerData* cc) const {
		cc->lastRecruitTime = now();
		cc->recruitBlobManager.set(true);
	}

	void haltBlobGranules(ClusterControllerData* cc, Optional<Standalone<StringRef>> pid) const {
		if (interface.present()) {
			cc->id_worker[pid].haltBlobManager =
			    brokenPromiseToNever(interface.get().haltBlobGranules.getReply(HaltBlobGranulesRequest(cc->id)));
		}
	}
};

struct EncryptKeyProxySingleton : Singleton<EncryptKeyProxyInterface> {

	EncryptKeyProxySingleton(const Optional<EncryptKeyProxyInterface>& interface) : Singleton(interface) {}

	Role getRole() const { return Role::ENCRYPT_KEY_PROXY; }
	ProcessClass::ClusterRole getClusterRole() const { return ProcessClass::EncryptKeyProxy; }

	void setInterfaceToDbInfo(ClusterControllerData* cc) const {
		if (interface.present()) {
			TraceEvent("CCEKP_SetInf", cc->id).detail("Id", interface.get().id());
			cc->db.setEncryptKeyProxy(interface.get());
		}
	}
	void halt(ClusterControllerData* cc, Optional<Standalone<StringRef>> pid) const {
		if (interface.present()) {
			cc->id_worker[pid].haltEncryptKeyProxy =
			    brokenPromiseToNever(interface.get().haltEncryptKeyProxy.getReply(HaltEncryptKeyProxyRequest(cc->id)));
		}
	}
	void recruit(ClusterControllerData* cc) const {
		cc->lastRecruitTime = now();
		cc->recruitEncryptKeyProxy.set(true);
	}
};

ACTOR Future<Void> handleLeaderReplacement(Reference<ClusterRecoveryData> self, Future<Void> leaderFail) {
	loop choose {
		when(wait(leaderFail)) {
			TraceEvent("LeaderReplaced", self->controllerData->id).log();
			// We are no longer the leader if this has changed.
			self->controllerData->shouldCommitSuicide = true;
			throw restart_cluster_controller();
		}
	}
}

ACTOR Future<Void> clusterWatchDatabase(ClusterControllerData* cluster,
                                        ClusterControllerData::DBInfo* db,
                                        ServerCoordinators coordinators,
                                        Future<Void> leaderFail) {
	state MasterInterface iMaster;
	state Reference<ClusterRecoveryData> recoveryData;
	state PromiseStream<Future<Void>> addActor;
	state Future<Void> recoveryCore;

	// SOMEDAY: If there is already a non-failed master referenced by zkMasterInfo, use that one until it fails
	// When this someday is implemented, make sure forced failures still cause the master to be recruited again

	loop {
		TraceEvent("CCWDB", cluster->id).log();
		try {
			state double recoveryStart = now();
			state MasterInterface newMaster;
			state Future<Void> collection;

			TraceEvent("CCWDB", cluster->id).detail("Recruiting", "Master");
			wait(recruitNewMaster(cluster, db, std::addressof(newMaster)));

			iMaster = newMaster;

			db->masterRegistrationCount = 0;
			db->recoveryStalled = false;

			auto dbInfo = ServerDBInfo();
			dbInfo.master = iMaster;
			dbInfo.id = deterministicRandom()->randomUniqueID();
			dbInfo.infoGeneration = ++db->dbInfoCount;
			dbInfo.masterLifetime = db->serverInfo->get().masterLifetime;
			++dbInfo.masterLifetime;
			dbInfo.clusterInterface = db->serverInfo->get().clusterInterface;
			dbInfo.distributor = db->serverInfo->get().distributor;
			dbInfo.ratekeeper = db->serverInfo->get().ratekeeper;
			dbInfo.blobManager = db->serverInfo->get().blobManager;
			dbInfo.encryptKeyProxy = db->serverInfo->get().encryptKeyProxy;
			dbInfo.latencyBandConfig = db->serverInfo->get().latencyBandConfig;
			dbInfo.myLocality = db->serverInfo->get().myLocality;
			dbInfo.client = ClientDBInfo();
			dbInfo.client.tenantMode = db->config.tenantMode;

			TraceEvent("CCWDB", cluster->id)
			    .detail("NewMaster", dbInfo.master.id().toString())
			    .detail("Lifetime", dbInfo.masterLifetime.toString())
			    .detail("ChangeID", dbInfo.id);
			db->serverInfo->set(dbInfo);

			state Future<Void> spinDelay = delay(
			    SERVER_KNOBS
			        ->MASTER_SPIN_DELAY); // Don't retry cluster recovery more than once per second, but don't delay
			                              // the "first" recovery after more than a second of normal operation

			TraceEvent("CCWDB", cluster->id).detail("Watching", iMaster.id());
			recoveryData = makeReference<ClusterRecoveryData>(cluster,
			                                                  db->serverInfo,
			                                                  db->serverInfo->get().master,
			                                                  db->serverInfo->get().masterLifetime,
			                                                  coordinators,
			                                                  db->serverInfo->get().clusterInterface,
			                                                  LiteralStringRef(""),
			                                                  addActor,
			                                                  db->forceRecovery);

			collection = actorCollection(recoveryData->addActor.getFuture());
			recoveryCore = clusterRecoveryCore(recoveryData);

			// Master failure detection is pretty sensitive, but if we are in the middle of a very long recovery we
			// really don't want to have to start over
			loop choose {
				when(wait(recoveryCore)) {}
				when(wait(waitFailureClient(
				              iMaster.waitFailure,
				              db->masterRegistrationCount
				                  ? SERVER_KNOBS->MASTER_FAILURE_REACTION_TIME
				                  : (now() - recoveryStart) * SERVER_KNOBS->MASTER_FAILURE_SLOPE_DURING_RECOVERY,
				              db->masterRegistrationCount ? -SERVER_KNOBS->MASTER_FAILURE_REACTION_TIME /
				                                                SERVER_KNOBS->SECONDS_BEFORE_NO_FAILURE_DELAY
				                                          : SERVER_KNOBS->MASTER_FAILURE_SLOPE_DURING_RECOVERY) ||
				          db->forceMasterFailure.onTrigger())) {
					break;
				}
				when(wait(db->serverInfo->onChange())) {}
				when(BackupWorkerDoneRequest req =
				         waitNext(db->serverInfo->get().clusterInterface.notifyBackupWorkerDone.getFuture())) {
					if (recoveryData->logSystem.isValid() && recoveryData->logSystem->removeBackupWorker(req)) {
						recoveryData->registrationTrigger.trigger();
					}
					++recoveryData->backupWorkerDoneRequests;
					req.reply.send(Void());
					TraceEvent(SevDebug, "BackupWorkerDoneRequest", cluster->id).log();
				}
				when(wait(collection)) { throw internal_error(); }
				when(wait(handleLeaderReplacement(recoveryData, leaderFail))) { throw internal_error(); }
			}
			// failed master (better master exists) could happen while change-coordinators request processing is
			// in-progress
			if (cluster->shouldCommitSuicide) {
				throw restart_cluster_controller();
			}

			recoveryCore.cancel();
			wait(cleanupRecoveryActorCollection(recoveryData, /*exThrown=*/false));
			ASSERT(addActor.isEmpty());

			wait(spinDelay);

			TEST(true); // clusterWatchDatabase() master failed
			TraceEvent(SevWarn, "DetectedFailedRecovery", cluster->id).detail("OldMaster", iMaster.id());
		} catch (Error& e) {
			state Error err = e;
			TraceEvent("CCWDB", cluster->id).errorUnsuppressed(e).detail("Master", iMaster.id());
			if (e.code() != error_code_actor_cancelled)
				wait(delay(0.0));

			recoveryCore.cancel();
			wait(cleanupRecoveryActorCollection(recoveryData, true /* exThrown */));
			ASSERT(addActor.isEmpty());

			TEST(err.code() == error_code_tlog_failed); // Terminated due to tLog failure
			TEST(err.code() == error_code_commit_proxy_failed); // Terminated due to commit proxy failure
			TEST(err.code() == error_code_grv_proxy_failed); // Terminated due to GRV proxy failure
			TEST(err.code() == error_code_resolver_failed); // Terminated due to resolver failure
			TEST(err.code() == error_code_backup_worker_failed); // Terminated due to backup worker failure
			TEST(err.code() == error_code_operation_failed); // Terminated due to failed operation
			TEST(err.code() == error_code_restart_cluster_controller); // Terminated due to cluster-controller restart.

			if (cluster->shouldCommitSuicide || err.code() == error_code_coordinators_changed) {
				TraceEvent("ClusterControllerTerminate", cluster->id).errorUnsuppressed(err);
				throw restart_cluster_controller();
			}

			if (isNormalClusterRecoveryError(err)) {
				TraceEvent(SevWarn, "ClusterRecoveryRetrying", cluster->id).error(err);
			} else {
				bool ok = err.code() == error_code_no_more_servers;
				TraceEvent(ok ? SevWarn : SevError, "ClusterWatchDatabaseRetrying", cluster->id).error(err);
				if (!ok)
					throw err;
			}
			wait(delay(SERVER_KNOBS->ATTEMPT_RECRUITMENT_DELAY));
		}
	}
}

ACTOR Future<Void> clusterGetServerInfo(ClusterControllerData::DBInfo* db,
                                        UID knownServerInfoID,
                                        ReplyPromise<ServerDBInfo> reply) {
	while (db->serverInfo->get().id == knownServerInfoID) {
		choose {
			when(wait(yieldedFuture(db->serverInfo->onChange()))) {}
			when(wait(delayJittered(300))) { break; } // The server might be long gone!
		}
	}
	reply.send(db->serverInfo->get());
	return Void();
}

ACTOR Future<Void> clusterOpenDatabase(ClusterControllerData::DBInfo* db, OpenDatabaseRequest req) {
	db->clientStatus[req.reply.getEndpoint().getPrimaryAddress()] = std::make_pair(now(), req);
	if (db->clientStatus.size() > 10000) {
		TraceEvent(SevWarnAlways, "TooManyClientStatusEntries").suppressFor(1.0);
	}

	while (db->clientInfo->get().id == req.knownClientInfoID) {
		choose {
			when(wait(db->clientInfo->onChange())) {}
			when(wait(delayJittered(SERVER_KNOBS->COORDINATOR_REGISTER_INTERVAL))) {
				break;
			} // The client might be long gone!
		}
	}

	req.reply.send(db->clientInfo->get());
	return Void();
}

void checkOutstandingRecruitmentRequests(ClusterControllerData* self) {
	for (int i = 0; i < self->outstandingRecruitmentRequests.size(); i++) {
		Reference<RecruitWorkersInfo> info = self->outstandingRecruitmentRequests[i];
		try {
			info->rep = self->findWorkersForConfiguration(info->req);
			if (info->dbgId.present()) {
				TraceEvent("CheckOutstandingRecruitment", info->dbgId.get())
				    .detail("Request", info->req.configuration.toString());
			}
			info->waitForCompletion.trigger();
			swapAndPop(&self->outstandingRecruitmentRequests, i--);
		} catch (Error& e) {
			if (e.code() == error_code_no_more_servers || e.code() == error_code_operation_failed) {
				TraceEvent(SevWarn, "RecruitTLogMatchingSetNotAvailable", self->id).error(e);
			} else {
				TraceEvent(SevError, "RecruitTLogsRequestError", self->id).error(e);
				throw;
			}
		}
	}
}

void checkOutstandingRemoteRecruitmentRequests(ClusterControllerData* self) {
	for (int i = 0; i < self->outstandingRemoteRecruitmentRequests.size(); i++) {
		Reference<RecruitRemoteWorkersInfo> info = self->outstandingRemoteRecruitmentRequests[i];
		try {
			info->rep = self->findRemoteWorkersForConfiguration(info->req);
			if (info->dbgId.present()) {
				TraceEvent("CheckOutstandingRemoteRecruitment", info->dbgId.get())
				    .detail("Request", info->req.configuration.toString());
			}
			info->waitForCompletion.trigger();
			swapAndPop(&self->outstandingRemoteRecruitmentRequests, i--);
		} catch (Error& e) {
			if (e.code() == error_code_no_more_servers || e.code() == error_code_operation_failed) {
				TraceEvent(SevWarn, "RecruitRemoteTLogMatchingSetNotAvailable", self->id).error(e);
			} else {
				TraceEvent(SevError, "RecruitRemoteTLogsRequestError", self->id).error(e);
				throw;
			}
		}
	}
}

void checkOutstandingStorageRequests(ClusterControllerData* self) {
	for (int i = 0; i < self->outstandingStorageRequests.size(); i++) {
		auto& req = self->outstandingStorageRequests[i];
		try {
			if (req.second < now()) {
				req.first.reply.sendError(timed_out());
				swapAndPop(&self->outstandingStorageRequests, i--);
			} else {
				if (!self->gotProcessClasses && !req.first.criticalRecruitment)
					throw no_more_servers();

				auto worker = self->getStorageWorker(req.first);
				RecruitStorageReply rep;
				rep.worker = worker.interf;
				rep.processClass = worker.processClass;
				req.first.reply.send(rep);
				swapAndPop(&self->outstandingStorageRequests, i--);
			}
		} catch (Error& e) {
			if (e.code() == error_code_no_more_servers) {
				TraceEvent(SevWarn, "RecruitStorageNotAvailable", self->id)
				    .errorUnsuppressed(e)
				    .suppressFor(1.0)
				    .detail("OutstandingReq", i)
				    .detail("IsCriticalRecruitment", req.first.criticalRecruitment);
			} else {
				TraceEvent(SevError, "RecruitStorageError", self->id).error(e);
				throw;
			}
		}
	}
}

// When workers aren't available at the time of request, the request
// gets added to a list of outstanding reqs. Here, we try to resolve these
// outstanding requests.
void checkOutstandingBlobWorkerRequests(ClusterControllerData* self) {
	for (int i = 0; i < self->outstandingBlobWorkerRequests.size(); i++) {
		auto& req = self->outstandingBlobWorkerRequests[i];
		try {
			if (req.second < now()) {
				req.first.reply.sendError(timed_out());
				swapAndPop(&self->outstandingBlobWorkerRequests, i--);
			} else {
				if (!self->gotProcessClasses)
					throw no_more_servers();

				auto worker = self->getBlobWorker(req.first);
				RecruitBlobWorkerReply rep;
				rep.worker = worker.interf;
				rep.processClass = worker.processClass;
				req.first.reply.send(rep);
				// can remove it once we know the worker was found
				swapAndPop(&self->outstandingBlobWorkerRequests, i--);
			}
		} catch (Error& e) {
			if (e.code() == error_code_no_more_servers) {
				TraceEvent(SevWarn, "RecruitBlobWorkerNotAvailable", self->id)
				    .errorUnsuppressed(e)
				    .suppressFor(1.0)
				    .detail("OutstandingReq", i);
			} else {
				TraceEvent(SevError, "RecruitBlobWorkerError", self->id).error(e);
				throw;
			}
		}
	}
}

// Finds and returns a new process for role
WorkerDetails findNewProcessForSingleton(ClusterControllerData* self,
                                         const ProcessClass::ClusterRole role,
                                         std::map<Optional<Standalone<StringRef>>, int>& id_used) {
	// find new process in cluster for role
	WorkerDetails newWorker =
	    self->getWorkerForRoleInDatacenter(
	            self->clusterControllerDcId, role, ProcessClass::NeverAssign, self->db.config, id_used, {}, true)
	        .worker;

	// check if master's process is actually better suited for role
	if (self->onMasterIsBetter(newWorker, role)) {
		newWorker = self->id_worker[self->masterProcessId.get()].details;
	}

	// acknowledge that the pid is now potentially used by this role as well
	id_used[newWorker.interf.locality.processId()]++;

	return newWorker;
}

// Return best possible fitness for singleton. Note that lower fitness is better.
ProcessClass::Fitness findBestFitnessForSingleton(const ClusterControllerData* self,
                                                  const WorkerDetails& worker,
                                                  const ProcessClass::ClusterRole& role) {
	auto bestFitness = worker.processClass.machineClassFitness(role);
	// If the process has been marked as excluded, we take the max with ExcludeFit to ensure its fit
	// is at least as bad as ExcludeFit. This assists with successfully offboarding such processes
	// and removing them from the cluster.
	if (self->db.config.isExcludedServer(worker.interf.addresses())) {
		bestFitness = std::max(bestFitness, ProcessClass::ExcludeFit);
	}
	return bestFitness;
}

// Returns true iff the singleton is healthy. "Healthy" here means that
// the singleton is stable (see below) and doesn't need to be rerecruited.
// Side effects: (possibly) initiates recruitment
template <class Interface>
bool isHealthySingleton(ClusterControllerData* self,
                        const WorkerDetails& newWorker,
                        const Singleton<Interface>& singleton,
                        const ProcessClass::Fitness& bestFitness,
                        const Optional<UID> recruitingID) {
	// A singleton is stable if it exists in cluster, has not been killed off of proc and is not being recruited
	bool isStableSingleton = singleton.interface.present() &&
	                         self->id_worker.count(singleton.interface.get().locality.processId()) &&
	                         (!recruitingID.present() || (recruitingID.get() == singleton.interface.get().id()));

	if (!isStableSingleton) {
		return false; // not healthy because unstable
	}

	auto& currWorker = self->id_worker[singleton.interface.get().locality.processId()];
	auto currFitness = currWorker.details.processClass.machineClassFitness(singleton.getClusterRole());
	if (currWorker.priorityInfo.isExcluded) {
		currFitness = ProcessClass::ExcludeFit;
	}
	// If any of the following conditions are met, we will switch the singleton's process:
	// - if the current proc is used by some non-master, non-singleton role
	// - if the current fitness is less than optimal (lower fitness is better)
	// - if currently at peak fitness but on same process as master, and the new worker is on different process
	bool shouldRerecruit =
	    self->isUsedNotMaster(currWorker.details.interf.locality.processId()) || bestFitness < currFitness ||
	    (currFitness == bestFitness && currWorker.details.interf.locality.processId() == self->masterProcessId &&
	     newWorker.interf.locality.processId() != self->masterProcessId);
	if (shouldRerecruit) {
		std::string roleAbbr = singleton.getRole().abbreviation;
		TraceEvent(("CCHalt" + roleAbbr).c_str(), self->id)
		    .detail(roleAbbr + "ID", singleton.interface.get().id())
		    .detail("Excluded", currWorker.priorityInfo.isExcluded)
		    .detail("Fitness", currFitness)
		    .detail("BestFitness", bestFitness);
		singleton.recruit(self); // SIDE EFFECT: initiating recruitment
		return false; // not healthy since needed to be rerecruited
	} else {
		return true; // healthy because doesn't need to be rerecruited
	}
}

// Returns a mapping from pid->pidCount for pids
std::map<Optional<Standalone<StringRef>>, int> getColocCounts(
    const std::vector<Optional<Standalone<StringRef>>>& pids) {
	std::map<Optional<Standalone<StringRef>>, int> counts;
	for (const auto& pid : pids) {
		if (pid.present()) {
			++counts[pid];
		}
	}
	return counts;
}

// Checks if there exists a better process for each singleton (e.g. DD) compared
// to the process it is currently on.
// Note: there is a lot of extra logic here to only recruit the blob manager when gate is open.
// When adding new singletons, just follow the ratekeeper/data distributor examples.
void checkBetterSingletons(ClusterControllerData* self) {
	if (!self->masterProcessId.present() ||
	    self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
		return;
	}

	// note: this map doesn't consider pids used by existing singletons
	std::map<Optional<Standalone<StringRef>>, int> id_used = self->getUsedIds();

	// We prefer spreading out other roles more than separating singletons on their own process
	// so we artificially amplify the pid count for the processes used by non-singleton roles.
	// In other words, we make the processes used for other roles less desirable to be used
	// by singletons as well.
	for (auto& it : id_used) {
		it.second *= PID_USED_AMP_FOR_NON_SINGLETON;
	}

	// Try to find a new process for each singleton.
	WorkerDetails newRKWorker = findNewProcessForSingleton(self, ProcessClass::Ratekeeper, id_used);
	WorkerDetails newDDWorker = findNewProcessForSingleton(self, ProcessClass::DataDistributor, id_used);

	WorkerDetails newBMWorker;
	if (self->db.blobGranulesEnabled.get()) {
		newBMWorker = findNewProcessForSingleton(self, ProcessClass::BlobManager, id_used);
	}

	WorkerDetails newEKPWorker;
	if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY) {
		newEKPWorker = findNewProcessForSingleton(self, ProcessClass::EncryptKeyProxy, id_used);
	}

	// Find best possible fitnesses for each singleton.
	auto bestFitnessForRK = findBestFitnessForSingleton(self, newRKWorker, ProcessClass::Ratekeeper);
	auto bestFitnessForDD = findBestFitnessForSingleton(self, newDDWorker, ProcessClass::DataDistributor);

	ProcessClass::Fitness bestFitnessForBM;
	if (self->db.blobGranulesEnabled.get()) {
		bestFitnessForBM = findBestFitnessForSingleton(self, newBMWorker, ProcessClass::BlobManager);
	}

	ProcessClass::Fitness bestFitnessForEKP;
	if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY) {
		bestFitnessForEKP = findBestFitnessForSingleton(self, newEKPWorker, ProcessClass::EncryptKeyProxy);
	}

	auto& db = self->db.serverInfo->get();
	auto rkSingleton = RatekeeperSingleton(db.ratekeeper);
	auto ddSingleton = DataDistributorSingleton(db.distributor);
	BlobManagerSingleton bmSingleton(db.blobManager);
	EncryptKeyProxySingleton ekpSingleton(db.encryptKeyProxy);

	// Check if the singletons are healthy.
	// side effect: try to rerecruit the singletons to more optimal processes
	bool rkHealthy = isHealthySingleton<RatekeeperInterface>(
	    self, newRKWorker, rkSingleton, bestFitnessForRK, self->recruitingRatekeeperID);

	bool ddHealthy = isHealthySingleton<DataDistributorInterface>(
	    self, newDDWorker, ddSingleton, bestFitnessForDD, self->recruitingDistributorID);

	bool bmHealthy = true;
	if (self->db.blobGranulesEnabled.get()) {
		bmHealthy = isHealthySingleton<BlobManagerInterface>(
		    self, newBMWorker, bmSingleton, bestFitnessForBM, self->recruitingBlobManagerID);
	}

	bool ekpHealthy = true;
	if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY) {
		ekpHealthy = isHealthySingleton<EncryptKeyProxyInterface>(
		    self, newEKPWorker, ekpSingleton, bestFitnessForEKP, self->recruitingEncryptKeyProxyID);
	}
	// if any of the singletons are unhealthy (rerecruited or not stable), then do not
	// consider any further re-recruitments
	if (!(rkHealthy && ddHealthy && bmHealthy && ekpHealthy)) {
		return;
	}

	// if we reach here, we know that the singletons are healthy so let's
	// check if we can colocate the singletons in a more optimal way
	Optional<Standalone<StringRef>> currRKProcessId = rkSingleton.interface.get().locality.processId();
	Optional<Standalone<StringRef>> currDDProcessId = ddSingleton.interface.get().locality.processId();
	Optional<Standalone<StringRef>> newRKProcessId = newRKWorker.interf.locality.processId();
	Optional<Standalone<StringRef>> newDDProcessId = newDDWorker.interf.locality.processId();

	Optional<Standalone<StringRef>> currBMProcessId, newBMProcessId;
	if (self->db.blobGranulesEnabled.get()) {
		currBMProcessId = bmSingleton.interface.get().locality.processId();
		newBMProcessId = newBMWorker.interf.locality.processId();
	}

	Optional<Standalone<StringRef>> currEKPProcessId, newEKPProcessId;
	if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY) {
		currEKPProcessId = ekpSingleton.interface.get().locality.processId();
		newEKPProcessId = newEKPWorker.interf.locality.processId();
	}

	std::vector<Optional<Standalone<StringRef>>> currPids = { currRKProcessId, currDDProcessId };
	std::vector<Optional<Standalone<StringRef>>> newPids = { newRKProcessId, newDDProcessId };
	if (self->db.blobGranulesEnabled.get()) {
		currPids.emplace_back(currBMProcessId);
		newPids.emplace_back(newBMProcessId);
	}

	if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY) {
		currPids.emplace_back(currEKPProcessId);
		newPids.emplace_back(newEKPProcessId);
	}

	auto currColocMap = getColocCounts(currPids);
	auto newColocMap = getColocCounts(newPids);

	// if the knob is disabled, the BM coloc counts should have no affect on the coloc counts check below
	if (!self->db.blobGranulesEnabled.get()) {
		ASSERT(currColocMap[currBMProcessId] == 0);
		ASSERT(newColocMap[newBMProcessId] == 0);
	}

	// if the knob is disabled, the EKP coloc counts should have no affect on the coloc counts check below
	if (!SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY) {
		ASSERT(currColocMap[currEKPProcessId] == 0);
		ASSERT(newColocMap[newEKPProcessId] == 0);
	}

	// if the new coloc counts are collectively better (i.e. each singleton's coloc count has not increased)
	if (newColocMap[newRKProcessId] <= currColocMap[currRKProcessId] &&
	    newColocMap[newDDProcessId] <= currColocMap[currDDProcessId] &&
	    newColocMap[newBMProcessId] <= currColocMap[currBMProcessId] &&
	    newColocMap[newEKPProcessId] <= currColocMap[currEKPProcessId]) {
		// rerecruit the singleton for which we have found a better process, if any
		if (newColocMap[newRKProcessId] < currColocMap[currRKProcessId]) {
			rkSingleton.recruit(self);
		} else if (newColocMap[newDDProcessId] < currColocMap[currDDProcessId]) {
			ddSingleton.recruit(self);
		} else if (self->db.blobGranulesEnabled.get() && newColocMap[newBMProcessId] < currColocMap[currBMProcessId]) {
			bmSingleton.recruit(self);
		} else if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY &&
		           newColocMap[newEKPProcessId] < currColocMap[currEKPProcessId]) {
			ekpSingleton.recruit(self);
		}
	}
}

ACTOR Future<Void> doCheckOutstandingRequests(ClusterControllerData* self) {
	try {
		wait(delay(SERVER_KNOBS->CHECK_OUTSTANDING_INTERVAL));
		while (now() - self->lastRecruitTime < SERVER_KNOBS->SINGLETON_RECRUIT_BME_DELAY ||
		       !self->goodRecruitmentTime.isReady()) {
			if (now() - self->lastRecruitTime < SERVER_KNOBS->SINGLETON_RECRUIT_BME_DELAY) {
				wait(delay(SERVER_KNOBS->SINGLETON_RECRUIT_BME_DELAY + 0.001 - (now() - self->lastRecruitTime)));
			}
			if (!self->goodRecruitmentTime.isReady()) {
				wait(self->goodRecruitmentTime);
			}
		}

		checkOutstandingRecruitmentRequests(self);
		checkOutstandingStorageRequests(self);

		if (self->db.blobGranulesEnabled.get()) {
			checkOutstandingBlobWorkerRequests(self);
		}
		checkBetterSingletons(self);

		self->checkRecoveryStalled();
		if (self->betterMasterExists()) {
			self->db.forceMasterFailure.trigger();
			TraceEvent("MasterRegistrationKill", self->id).detail("MasterId", self->db.serverInfo->get().master.id());
		}
	} catch (Error& e) {
		if (e.code() != error_code_no_more_servers) {
			TraceEvent(SevError, "CheckOutstandingError").error(e);
		}
	}
	return Void();
}

ACTOR Future<Void> doCheckOutstandingRemoteRequests(ClusterControllerData* self) {
	try {
		wait(delay(SERVER_KNOBS->CHECK_OUTSTANDING_INTERVAL));
		while (!self->goodRemoteRecruitmentTime.isReady()) {
			wait(self->goodRemoteRecruitmentTime);
		}

		checkOutstandingRemoteRecruitmentRequests(self);
	} catch (Error& e) {
		if (e.code() != error_code_no_more_servers) {
			TraceEvent(SevError, "CheckOutstandingError").error(e);
		}
	}
	return Void();
}

void checkOutstandingRequests(ClusterControllerData* self) {
	if (self->outstandingRemoteRequestChecker.isReady()) {
		self->outstandingRemoteRequestChecker = doCheckOutstandingRemoteRequests(self);
	}

	if (self->outstandingRequestChecker.isReady()) {
		self->outstandingRequestChecker = doCheckOutstandingRequests(self);
	}
}

ACTOR Future<Void> rebootAndCheck(ClusterControllerData* cluster, Optional<Standalone<StringRef>> processID) {
	{
		auto watcher = cluster->id_worker.find(processID);
		ASSERT(watcher != cluster->id_worker.end());

		watcher->second.reboots++;
		wait(delay(g_network->isSimulated() ? SERVER_KNOBS->SIM_SHUTDOWN_TIMEOUT : SERVER_KNOBS->SHUTDOWN_TIMEOUT));
	}

	{
		auto watcher = cluster->id_worker.find(processID);
		if (watcher != cluster->id_worker.end()) {
			watcher->second.reboots--;
			if (watcher->second.reboots < 2)
				checkOutstandingRequests(cluster);
		}
	}

	return Void();
}

ACTOR Future<Void> workerAvailabilityWatch(WorkerInterface worker,
                                           ProcessClass startingClass,
                                           ClusterControllerData* cluster) {
	state Future<Void> failed =
	    (worker.address() == g_network->getLocalAddress() || startingClass.classType() == ProcessClass::TesterClass)
	        ? Never()
	        : waitFailureClient(worker.waitFailure, SERVER_KNOBS->WORKER_FAILURE_TIME);
	cluster->updateWorkerList.set(worker.locality.processId(),
	                              ProcessData(worker.locality, startingClass, worker.stableAddress()));
	// This switching avoids a race where the worker can be added to id_worker map after the workerAvailabilityWatch
	// fails for the worker.
	wait(delay(0));

	loop {
		choose {
			when(wait(IFailureMonitor::failureMonitor().onStateEqual(
			    worker.storage.getEndpoint(),
			    FailureStatus(
			        IFailureMonitor::failureMonitor().getState(worker.storage.getEndpoint()).isAvailable())))) {
				if (IFailureMonitor::failureMonitor().getState(worker.storage.getEndpoint()).isAvailable()) {
					cluster->ac.add(rebootAndCheck(cluster, worker.locality.processId()));
					checkOutstandingRequests(cluster);
				}
			}
			when(wait(failed)) { // remove workers that have failed
				WorkerInfo& failedWorkerInfo = cluster->id_worker[worker.locality.processId()];

				if (!failedWorkerInfo.reply.isSet()) {
					failedWorkerInfo.reply.send(
					    RegisterWorkerReply(failedWorkerInfo.details.processClass, failedWorkerInfo.priorityInfo));
				}
				if (worker.locality.processId() == cluster->masterProcessId) {
					cluster->masterProcessId = Optional<Key>();
				}
				TraceEvent("ClusterControllerWorkerFailed", cluster->id)
				    .detail("ProcessId", worker.locality.processId())
				    .detail("ProcessClass", failedWorkerInfo.details.processClass.toString())
				    .detail("Address", worker.address());
				cluster->removedDBInfoEndpoints.insert(worker.updateServerDBInfo.getEndpoint());
				cluster->id_worker.erase(worker.locality.processId());
				cluster->updateWorkerList.set(worker.locality.processId(), Optional<ProcessData>());
				return Void();
			}
		}
	}
}

struct FailureStatusInfo {
	FailureStatus status;
	double lastRequestTime;
	double penultimateRequestTime;

	FailureStatusInfo() : lastRequestTime(0), penultimateRequestTime(0) {}

	void insertRequest(double now) {
		penultimateRequestTime = lastRequestTime;
		lastRequestTime = now;
	}

	double latency(double now) const {
		return std::max(now - lastRequestTime, lastRequestTime - penultimateRequestTime);
	}
};

ACTOR Future<std::vector<TLogInterface>> requireAll(std::vector<Future<Optional<std::vector<TLogInterface>>>> in) {
	state std::vector<TLogInterface> out;
	state int i;
	for (i = 0; i < in.size(); i++) {
		Optional<std::vector<TLogInterface>> x = wait(in[i]);
		if (!x.present())
			throw recruitment_failed();
		out.insert(out.end(), x.get().begin(), x.get().end());
	}
	return out;
}

void clusterRecruitStorage(ClusterControllerData* self, RecruitStorageRequest req) {
	try {
		if (!self->gotProcessClasses && !req.criticalRecruitment)
			throw no_more_servers();
		auto worker = self->getStorageWorker(req);
		RecruitStorageReply rep;
		rep.worker = worker.interf;
		rep.processClass = worker.processClass;
		req.reply.send(rep);
	} catch (Error& e) {
		if (e.code() == error_code_no_more_servers) {
			self->outstandingStorageRequests.emplace_back(req, now() + SERVER_KNOBS->RECRUITMENT_TIMEOUT);
			TraceEvent(SevWarn, "RecruitStorageNotAvailable", self->id)
			    .error(e)
			    .detail("IsCriticalRecruitment", req.criticalRecruitment);
		} else {
			TraceEvent(SevError, "RecruitStorageError", self->id).error(e);
			throw; // Any other error will bring down the cluster controller
		}
	}
}

// Trys to send a reply to req with a worker (process) that a blob worker can be recruited on
// Otherwise, add the req to a list of outstanding reqs that will eventually be dealt with
void clusterRecruitBlobWorker(ClusterControllerData* self, RecruitBlobWorkerRequest req) {
	try {
		if (!self->gotProcessClasses)
			throw no_more_servers();
		auto worker = self->getBlobWorker(req);
		RecruitBlobWorkerReply rep;
		rep.worker = worker.interf;
		rep.processClass = worker.processClass;
		req.reply.send(rep);
	} catch (Error& e) {
		if (e.code() == error_code_no_more_servers) {
			self->outstandingBlobWorkerRequests.emplace_back(req, now() + SERVER_KNOBS->RECRUITMENT_TIMEOUT);
			TraceEvent(SevWarn, "RecruitBlobWorkerNotAvailable", self->id).error(e);
		} else {
			TraceEvent(SevError, "RecruitBlobWorkerError", self->id).error(e);
			throw; // Any other error will bring down the cluster controller
		}
	}
}

void clusterRegisterMaster(ClusterControllerData* self, RegisterMasterRequest const& req) {
	req.reply.send(Void());

	TraceEvent("MasterRegistrationReceived", self->id)
	    .detail("MasterId", req.id)
	    .detail("Master", req.mi.toString())
	    .detail("Tlogs", describe(req.logSystemConfig.tLogs))
	    .detail("Resolvers", req.resolvers.size())
	    .detail("RecoveryState", (int)req.recoveryState)
	    .detail("RegistrationCount", req.registrationCount)
	    .detail("CommitProxies", req.commitProxies.size())
	    .detail("GrvProxies", req.grvProxies.size())
	    .detail("RecoveryCount", req.recoveryCount)
	    .detail("Stalled", req.recoveryStalled)
	    .detail("OldestBackupEpoch", req.logSystemConfig.oldestBackupEpoch)
	    .detail("ClusterId", req.clusterId);

	// make sure the request comes from an active database
	auto db = &self->db;
	if (db->serverInfo->get().master.id() != req.id || req.registrationCount <= db->masterRegistrationCount) {
		TraceEvent("MasterRegistrationNotFound", self->id)
		    .detail("MasterId", req.id)
		    .detail("ExistingId", db->serverInfo->get().master.id())
		    .detail("RegCount", req.registrationCount)
		    .detail("ExistingRegCount", db->masterRegistrationCount);
		return;
	}

	if (req.recoveryState == RecoveryState::FULLY_RECOVERED) {
		self->db.unfinishedRecoveries = 0;
		self->db.logGenerations = 0;
		ASSERT(!req.logSystemConfig.oldTLogs.size());
	} else {
		self->db.logGenerations = std::max<int>(self->db.logGenerations, req.logSystemConfig.oldTLogs.size());
	}

	db->masterRegistrationCount = req.registrationCount;
	db->recoveryStalled = req.recoveryStalled;
	if (req.configuration.present()) {
		db->config = req.configuration.get();

		if (req.recoveryState >= RecoveryState::ACCEPTING_COMMITS) {
			self->gotFullyRecoveredConfig = true;
			db->fullyRecoveredConfig = req.configuration.get();
			for (auto& it : self->id_worker) {
				bool isExcludedFromConfig =
				    db->fullyRecoveredConfig.isExcludedServer(it.second.details.interf.addresses());
				if (it.second.priorityInfo.isExcluded != isExcludedFromConfig) {
					it.second.priorityInfo.isExcluded = isExcludedFromConfig;
					if (!it.second.reply.isSet()) {
						it.second.reply.send(
						    RegisterWorkerReply(it.second.details.processClass, it.second.priorityInfo));
					}
				}
			}
		}
	}

	bool isChanged = false;
	auto dbInfo = self->db.serverInfo->get();

	if (dbInfo.recoveryState != req.recoveryState) {
		dbInfo.recoveryState = req.recoveryState;
		isChanged = true;
	}

	if (dbInfo.priorCommittedLogServers != req.priorCommittedLogServers) {
		dbInfo.priorCommittedLogServers = req.priorCommittedLogServers;
		isChanged = true;
	}

	// Construct the client information
	if (db->clientInfo->get().commitProxies != req.commitProxies ||
	    db->clientInfo->get().grvProxies != req.grvProxies ||
	    db->clientInfo->get().tenantMode != db->config.tenantMode) {
		TraceEvent("PublishNewClientInfo", self->id)
		    .detail("Master", dbInfo.master.id())
		    .detail("GrvProxies", db->clientInfo->get().grvProxies)
		    .detail("ReqGrvProxies", req.grvProxies)
		    .detail("CommitProxies", db->clientInfo->get().commitProxies)
		    .detail("ReqCPs", req.commitProxies)
		    .detail("TenantMode", db->clientInfo->get().tenantMode.toString())
		    .detail("ReqTenantMode", db->config.tenantMode.toString());
		isChanged = true;
		// TODO why construct a new one and not just copy the old one and change proxies + id?
		ClientDBInfo clientInfo;
		clientInfo.id = deterministicRandom()->randomUniqueID();
		clientInfo.commitProxies = req.commitProxies;
		clientInfo.grvProxies = req.grvProxies;
		clientInfo.tenantMode = db->config.tenantMode;
		db->clientInfo->set(clientInfo);
		dbInfo.client = db->clientInfo->get();
	}

	if (!dbInfo.logSystemConfig.isEqual(req.logSystemConfig)) {
		isChanged = true;
		dbInfo.logSystemConfig = req.logSystemConfig;
	}

	if (dbInfo.resolvers != req.resolvers) {
		isChanged = true;
		dbInfo.resolvers = req.resolvers;
	}

	if (dbInfo.recoveryCount != req.recoveryCount) {
		isChanged = true;
		dbInfo.recoveryCount = req.recoveryCount;
	}

	if (dbInfo.clusterId != req.clusterId) {
		isChanged = true;
		dbInfo.clusterId = req.clusterId;
	}

	if (isChanged) {
		dbInfo.id = deterministicRandom()->randomUniqueID();
		dbInfo.infoGeneration = ++self->db.dbInfoCount;
		self->db.serverInfo->set(dbInfo);
	}

	checkOutstandingRequests(self);
}

// Halts the registering (i.e. requesting) singleton if one is already in the process of being recruited
// or, halts the existing singleton in favour of the requesting one
template <class Interface>
void haltRegisteringOrCurrentSingleton(ClusterControllerData* self,
                                       const WorkerInterface& worker,
                                       const Singleton<Interface>& currSingleton,
                                       const Singleton<Interface>& registeringSingleton,
                                       const Optional<UID> recruitingID) {
	ASSERT(currSingleton.getRole() == registeringSingleton.getRole());
	const UID registeringID = registeringSingleton.interface.get().id();
	const std::string roleName = currSingleton.getRole().roleName;
	const std::string roleAbbr = currSingleton.getRole().abbreviation;

	// halt the requesting singleton if it isn't the one currently being recruited
	if ((recruitingID.present() && recruitingID.get() != registeringID) ||
	    self->clusterControllerDcId != worker.locality.dcId()) {
		TraceEvent(("CCHaltRegistering" + roleName).c_str(), self->id)
		    .detail(roleAbbr + "ID", registeringID)
		    .detail("DcID", printable(self->clusterControllerDcId))
		    .detail("ReqDcID", printable(worker.locality.dcId()))
		    .detail("Recruiting" + roleAbbr + "ID", recruitingID.present() ? recruitingID.get() : UID());
		registeringSingleton.halt(self, worker.locality.processId());
	} else if (!recruitingID.present()) {
		// if not currently recruiting, then halt previous one in favour of requesting one
		TraceEvent(("CCRegister" + roleName).c_str(), self->id).detail(roleAbbr + "ID", registeringID);
		if (currSingleton.interface.present() && currSingleton.interface.get().id() != registeringID &&
		    self->id_worker.count(currSingleton.interface.get().locality.processId())) {
			TraceEvent(("CCHaltPrevious" + roleName).c_str(), self->id)
			    .detail(roleAbbr + "ID", currSingleton.interface.get().id())
			    .detail("DcID", printable(self->clusterControllerDcId))
			    .detail("ReqDcID", printable(worker.locality.dcId()))
			    .detail("Recruiting" + roleAbbr + "ID", recruitingID.present() ? recruitingID.get() : UID());
			currSingleton.halt(self, currSingleton.interface.get().locality.processId());
		}
		// set the curr singleton if it doesn't exist or its different from the requesting one
		if (!currSingleton.interface.present() || currSingleton.interface.get().id() != registeringID) {
			registeringSingleton.setInterfaceToDbInfo(self);
		}
	}
}

void registerWorker(RegisterWorkerRequest req,
                    ClusterControllerData* self,
                    ServerCoordinators coordinators,
                    ConfigBroadcaster* configBroadcaster) {
	const WorkerInterface& w = req.wi;
	ProcessClass newProcessClass = req.processClass;
	auto info = self->id_worker.find(w.locality.processId());
	ClusterControllerPriorityInfo newPriorityInfo = req.priorityInfo;
	newPriorityInfo.processClassFitness = newProcessClass.machineClassFitness(ProcessClass::ClusterController);
	Optional<ConfigFollowerInterface> cfi;
	bool isCoordinator =
	    std::find_if(coordinators.configServers.begin(),
	                 coordinators.configServers.end(),
	                 [&req](const ConfigFollowerInterface& cfi) {
		                 return cfi.address() == req.wi.address() || (req.wi.secondaryAddress().present() &&
		                                                              cfi.address() == req.wi.secondaryAddress().get());
	                 }) != coordinators.configServers.end();

	for (auto it : req.incompatiblePeers) {
		self->db.incompatibleConnections[it] = now() + SERVER_KNOBS->INCOMPATIBLE_PEERS_LOGGING_INTERVAL;
	}
	self->removedDBInfoEndpoints.erase(w.updateServerDBInfo.getEndpoint());

	if (info == self->id_worker.end()) {
		TraceEvent("ClusterControllerActualWorkers", self->id)
		    .detail("WorkerId", w.id())
		    .detail("ProcessId", w.locality.processId())
		    .detail("ZoneId", w.locality.zoneId())
		    .detail("DataHall", w.locality.dataHallId())
		    .detail("PClass", req.processClass.toString())
		    .detail("Workers", self->id_worker.size());
		self->goodRecruitmentTime = lowPriorityDelay(SERVER_KNOBS->WAIT_FOR_GOOD_RECRUITMENT_DELAY);
		self->goodRemoteRecruitmentTime = lowPriorityDelay(SERVER_KNOBS->WAIT_FOR_GOOD_REMOTE_RECRUITMENT_DELAY);
	} else {
		TraceEvent("ClusterControllerWorkerAlreadyRegistered", self->id)
		    .suppressFor(1.0)
		    .detail("WorkerId", w.id())
		    .detail("ProcessId", w.locality.processId())
		    .detail("ZoneId", w.locality.zoneId())
		    .detail("DataHall", w.locality.dataHallId())
		    .detail("PClass", req.processClass.toString())
		    .detail("Workers", self->id_worker.size())
		    .detail("Degraded", req.degraded);
	}
	if (w.address() == g_network->getLocalAddress()) {
		if (self->changingDcIds.get().first) {
			if (self->changingDcIds.get().second.present()) {
				newPriorityInfo.dcFitness = ClusterControllerPriorityInfo::calculateDCFitness(
				    w.locality.dcId(), self->changingDcIds.get().second.get());
			}
		} else if (self->changedDcIds.get().second.present()) {
			newPriorityInfo.dcFitness = ClusterControllerPriorityInfo::calculateDCFitness(
			    w.locality.dcId(), self->changedDcIds.get().second.get());
		}
	} else {
		if (!self->changingDcIds.get().first) {
			if (self->changingDcIds.get().second.present()) {
				newPriorityInfo.dcFitness = ClusterControllerPriorityInfo::calculateDCFitness(
				    w.locality.dcId(), self->changingDcIds.get().second.get());
			}
		} else if (self->changedDcIds.get().second.present()) {
			newPriorityInfo.dcFitness = ClusterControllerPriorityInfo::calculateDCFitness(
			    w.locality.dcId(), self->changedDcIds.get().second.get());
		}
	}

	// Check process class and exclusive property
	if (info == self->id_worker.end() || info->second.details.interf.id() != w.id() ||
	    req.generation >= info->second.gen) {
		if (self->gotProcessClasses) {
			auto classIter = self->id_class.find(w.locality.processId());

			if (classIter != self->id_class.end() && (classIter->second.classSource() == ProcessClass::DBSource ||
			                                          req.initialClass.classType() == ProcessClass::UnsetClass)) {
				newProcessClass = classIter->second;
			} else {
				newProcessClass = req.initialClass;
			}
			newPriorityInfo.processClassFitness = newProcessClass.machineClassFitness(ProcessClass::ClusterController);
		}

		if (self->gotFullyRecoveredConfig) {
			newPriorityInfo.isExcluded = self->db.fullyRecoveredConfig.isExcludedServer(w.addresses());
		}
	}

	if (info == self->id_worker.end()) {
		self->id_worker[w.locality.processId()] = WorkerInfo(workerAvailabilityWatch(w, newProcessClass, self),
		                                                     req.reply,
		                                                     req.generation,
		                                                     w,
		                                                     req.initialClass,
		                                                     newProcessClass,
		                                                     newPriorityInfo,
		                                                     req.degraded,
		                                                     req.issues);
		if (!self->masterProcessId.present() &&
		    w.locality.processId() == self->db.serverInfo->get().master.locality.processId()) {
			self->masterProcessId = w.locality.processId();
		}
		if (configBroadcaster != nullptr && isCoordinator) {
			self->addActor.send(configBroadcaster->registerNode(
			    w,
			    req.lastSeenKnobVersion,
			    req.knobConfigClassSet,
			    self->id_worker[w.locality.processId()].watcher,
			    self->id_worker[w.locality.processId()].details.interf.configBroadcastInterface));
		}
		self->updateDBInfoEndpoints.insert(w.updateServerDBInfo.getEndpoint());
		self->updateDBInfo.trigger();
		checkOutstandingRequests(self);
	} else if (info->second.details.interf.id() != w.id() || req.generation >= info->second.gen) {
		if (!info->second.reply.isSet()) {
			info->second.reply.send(Never());
		}
		info->second.reply = req.reply;
		info->second.details.processClass = newProcessClass;
		info->second.priorityInfo = newPriorityInfo;
		info->second.initialClass = req.initialClass;
		info->second.details.degraded = req.degraded;
		info->second.gen = req.generation;
		info->second.issues = req.issues;

		if (info->second.details.interf.id() != w.id()) {
			self->removedDBInfoEndpoints.insert(info->second.details.interf.updateServerDBInfo.getEndpoint());
			info->second.details.interf = w;
			info->second.watcher = workerAvailabilityWatch(w, newProcessClass, self);
		}
		if (req.requestDbInfo) {
			self->updateDBInfoEndpoints.insert(w.updateServerDBInfo.getEndpoint());
			self->updateDBInfo.trigger();
		}
		if (configBroadcaster != nullptr && isCoordinator) {
			self->addActor.send(configBroadcaster->registerNode(w,
			                                                    req.lastSeenKnobVersion,
			                                                    req.knobConfigClassSet,
			                                                    info->second.watcher,
			                                                    info->second.details.interf.configBroadcastInterface));
		}
		checkOutstandingRequests(self);
	} else {
		TEST(true); // Received an old worker registration request.
	}

	// For each singleton
	// - if the registering singleton conflicts with the singleton being recruited, kill the registering one
	// - if the singleton is not being recruited, kill the existing one in favour of the registering one
	if (req.distributorInterf.present()) {
		auto currSingleton = DataDistributorSingleton(self->db.serverInfo->get().distributor);
		auto registeringSingleton = DataDistributorSingleton(req.distributorInterf);
		haltRegisteringOrCurrentSingleton<DataDistributorInterface>(
		    self, w, currSingleton, registeringSingleton, self->recruitingDistributorID);
	}

	if (req.ratekeeperInterf.present()) {
		auto currSingleton = RatekeeperSingleton(self->db.serverInfo->get().ratekeeper);
		auto registeringSingleton = RatekeeperSingleton(req.ratekeeperInterf);
		haltRegisteringOrCurrentSingleton<RatekeeperInterface>(
		    self, w, currSingleton, registeringSingleton, self->recruitingRatekeeperID);
	}

	if (self->db.blobGranulesEnabled.get() && req.blobManagerInterf.present()) {
		auto currSingleton = BlobManagerSingleton(self->db.serverInfo->get().blobManager);
		auto registeringSingleton = BlobManagerSingleton(req.blobManagerInterf);
		haltRegisteringOrCurrentSingleton<BlobManagerInterface>(
		    self, w, currSingleton, registeringSingleton, self->recruitingBlobManagerID);
	}

	if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY && req.encryptKeyProxyInterf.present()) {
		auto currSingleton = EncryptKeyProxySingleton(self->db.serverInfo->get().encryptKeyProxy);
		auto registeringSingleton = EncryptKeyProxySingleton(req.encryptKeyProxyInterf);
		haltRegisteringOrCurrentSingleton<EncryptKeyProxyInterface>(
		    self, w, currSingleton, registeringSingleton, self->recruitingEncryptKeyProxyID);
	}

	// Notify the worker to register again with new process class/exclusive property
	if (!req.reply.isSet() && newPriorityInfo != req.priorityInfo) {
		req.reply.send(RegisterWorkerReply(newProcessClass, newPriorityInfo));
	}
}

#define TIME_KEEPER_VERSION LiteralStringRef("1")

ACTOR Future<Void> timeKeeperSetVersion(ClusterControllerData* self) {
	state Reference<ReadYourWritesTransaction> tr = makeReference<ReadYourWritesTransaction>(self->cx);
	loop {
		try {
			tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
			tr->setOption(FDBTransactionOptions::LOCK_AWARE);
			tr->setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);
			tr->set(timeKeeperVersionKey, TIME_KEEPER_VERSION);
			wait(tr->commit());
			break;
		} catch (Error& e) {
			wait(tr->onError(e));
		}
	}

	return Void();
}

// This actor periodically gets read version and writes it to cluster with current timestamp as key. To avoid
// running out of space, it limits the max number of entries and clears old entries on each update. This mapping is
// used from backup and restore to get the version information for a timestamp.
ACTOR Future<Void> timeKeeper(ClusterControllerData* self) {
	state KeyBackedMap<int64_t, Version> versionMap(timeKeeperPrefixRange.begin);

	TraceEvent("TimeKeeperStarted").log();

	wait(timeKeeperSetVersion(self));

	loop {
		state Reference<ReadYourWritesTransaction> tr = makeReference<ReadYourWritesTransaction>(self->cx);
		loop {
			try {
				state UID debugID = deterministicRandom()->randomUniqueID();
				if (!g_network->isSimulated()) {
					// This is done to provide an arbitrary logged transaction every ~10s.
					// FIXME: replace or augment this with logging on the proxy which tracks
					// how long it is taking to hear responses from each other component.
					tr->debugTransaction(debugID);
				}
				tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
				tr->setOption(FDBTransactionOptions::LOCK_AWARE);
				tr->setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);

				Optional<Value> disableValue = wait(tr->get(timeKeeperDisableKey));
				if (disableValue.present()) {
					break;
				}

				Version v = tr->getReadVersion().get();
				int64_t currentTime = (int64_t)now();
				versionMap.set(tr, currentTime, v);
				if (!g_network->isSimulated()) {
					TraceEvent("TimeKeeperCommit", debugID).detail("Version", v);
				}
				int64_t ttl = currentTime - SERVER_KNOBS->TIME_KEEPER_DELAY * SERVER_KNOBS->TIME_KEEPER_MAX_ENTRIES;
				if (ttl > 0) {
					versionMap.erase(tr, 0, ttl);
				}

				wait(tr->commit());
				break;
			} catch (Error& e) {
				wait(tr->onError(e));
			}
		}

		wait(delay(SERVER_KNOBS->TIME_KEEPER_DELAY));
	}
}

ACTOR Future<Void> statusServer(FutureStream<StatusRequest> requests,
                                ClusterControllerData* self,
                                ServerCoordinators coordinators,
                                ConfigBroadcaster const* configBroadcaster) {
	// Seconds since the END of the last GetStatus executed
	state double last_request_time = 0.0;

	// Place to accumulate a batch of requests to respond to
	state std::vector<StatusRequest> requests_batch;

	loop {
		try {
			// Wait til first request is ready
			StatusRequest req = waitNext(requests);
			++self->statusRequests;
			requests_batch.push_back(req);

			// Earliest time at which we may begin a new request
			double next_allowed_request_time = last_request_time + SERVER_KNOBS->STATUS_MIN_TIME_BETWEEN_REQUESTS;

			// Wait if needed to satisfy min_time knob, also allows more requets to queue up.
			double minwait = std::max(next_allowed_request_time - now(), 0.0);
			wait(delay(minwait));

			// Get all requests that are ready right *now*, before GetStatus() begins.
			// All of these requests will be responded to with the next GetStatus() result.
			// If requests are batched, do not respond to more than MAX_STATUS_REQUESTS_PER_SECOND
			// requests per second
			while (requests.isReady()) {
				auto req = requests.pop();
				if (SERVER_KNOBS->STATUS_MIN_TIME_BETWEEN_REQUESTS > 0.0 &&
				    requests_batch.size() + 1 >
				        SERVER_KNOBS->STATUS_MIN_TIME_BETWEEN_REQUESTS * SERVER_KNOBS->MAX_STATUS_REQUESTS_PER_SECOND) {
					TraceEvent(SevWarnAlways, "TooManyStatusRequests")
					    .suppressFor(1.0)
					    .detail("BatchSize", requests_batch.size());
					req.reply.sendError(server_overloaded());
				} else {
					requests_batch.push_back(req);
				}
			}

			// Get status but trap errors to send back to client.
			std::vector<WorkerDetails> workers;
			std::vector<ProcessIssues> workerIssues;

			for (auto& it : self->id_worker) {
				workers.push_back(it.second.details);
				if (it.second.issues.size()) {
					workerIssues.emplace_back(it.second.details.interf.address(), it.second.issues);
				}
			}

			std::vector<NetworkAddress> incompatibleConnections;
			for (auto it = self->db.incompatibleConnections.begin(); it != self->db.incompatibleConnections.end();) {
				if (it->second < now()) {
					it = self->db.incompatibleConnections.erase(it);
				} else {
					incompatibleConnections.push_back(it->first);
					it++;
				}
			}

			state ErrorOr<StatusReply> result = wait(errorOr(clusterGetStatus(self->db.serverInfo,
			                                                                  self->cx,
			                                                                  workers,
			                                                                  workerIssues,
			                                                                  &self->db.clientStatus,
			                                                                  coordinators,
			                                                                  incompatibleConnections,
			                                                                  self->datacenterVersionDifference,
			                                                                  configBroadcaster)));

			if (result.isError() && result.getError().code() == error_code_actor_cancelled)
				throw result.getError();

			// Update last_request_time now because GetStatus is finished and the delay is to be measured between
			// requests
			last_request_time = now();

			while (!requests_batch.empty()) {
				if (result.isError())
					requests_batch.back().reply.sendError(result.getError());
				else
					requests_batch.back().reply.send(result.get());
				requests_batch.pop_back();
				wait(yield());
			}
		} catch (Error& e) {
			TraceEvent(SevError, "StatusServerError").error(e);
			throw e;
		}
	}
}

ACTOR Future<Void> monitorProcessClasses(ClusterControllerData* self) {

	state ReadYourWritesTransaction trVer(self->db.db);
	loop {
		try {
			trVer.setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
			trVer.setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);

			Optional<Value> val = wait(trVer.get(processClassVersionKey));

			if (val.present())
				break;

			RangeResult processClasses = wait(trVer.getRange(processClassKeys, CLIENT_KNOBS->TOO_MANY));
			ASSERT(!processClasses.more && processClasses.size() < CLIENT_KNOBS->TOO_MANY);

			trVer.clear(processClassKeys);
			trVer.set(processClassVersionKey, processClassVersionValue);
			for (auto it : processClasses) {
				UID processUid = decodeProcessClassKeyOld(it.key);
				trVer.set(processClassKeyFor(processUid.toString()), it.value);
			}

			wait(trVer.commit());
			TraceEvent("ProcessClassUpgrade").log();
			break;
		} catch (Error& e) {
			wait(trVer.onError(e));
		}
	}

	loop {
		state ReadYourWritesTransaction tr(self->db.db);

		loop {
			try {
				tr.setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
				tr.setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);
				RangeResult processClasses = wait(tr.getRange(processClassKeys, CLIENT_KNOBS->TOO_MANY));
				ASSERT(!processClasses.more && processClasses.size() < CLIENT_KNOBS->TOO_MANY);

				if (processClasses != self->lastProcessClasses || !self->gotProcessClasses) {
					self->id_class.clear();
					for (int i = 0; i < processClasses.size(); i++) {
						auto c = decodeProcessClassValue(processClasses[i].value);
						ASSERT(c.classSource() != ProcessClass::CommandLineSource);
						self->id_class[decodeProcessClassKey(processClasses[i].key)] = c;
					}

					for (auto& w : self->id_worker) {
						auto classIter = self->id_class.find(w.first);
						ProcessClass newProcessClass;

						if (classIter != self->id_class.end() &&
						    (classIter->second.classSource() == ProcessClass::DBSource ||
						     w.second.initialClass.classType() == ProcessClass::UnsetClass)) {
							newProcessClass = classIter->second;
						} else {
							newProcessClass = w.second.initialClass;
						}

						if (newProcessClass != w.second.details.processClass) {
							w.second.details.processClass = newProcessClass;
							w.second.priorityInfo.processClassFitness =
							    newProcessClass.machineClassFitness(ProcessClass::ClusterController);
							if (!w.second.reply.isSet()) {
								w.second.reply.send(
								    RegisterWorkerReply(w.second.details.processClass, w.second.priorityInfo));
							}
						}
					}

					self->lastProcessClasses = processClasses;
					self->gotProcessClasses = true;
					checkOutstandingRequests(self);
				}

				state Future<Void> watchFuture = tr.watch(processClassChangeKey);
				wait(tr.commit());
				wait(watchFuture);
				break;
			} catch (Error& e) {
				wait(tr.onError(e));
			}
		}
	}
}

ACTOR Future<Void> monitorServerInfoConfig(ClusterControllerData::DBInfo* db) {
	loop {
		state ReadYourWritesTransaction tr(db->db);
		loop {
			try {
				tr.setOption(FDBTransactionOptions::READ_SYSTEM_KEYS);
				tr.setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);
				tr.setOption(FDBTransactionOptions::READ_LOCK_AWARE);

				Optional<Value> configVal = wait(tr.get(latencyBandConfigKey));
				Optional<LatencyBandConfig> config;
				if (configVal.present()) {
					config = LatencyBandConfig::parse(configVal.get());
				}

				auto serverInfo = db->serverInfo->get();
				if (config != serverInfo.latencyBandConfig) {
					TraceEvent("LatencyBandConfigChanged").detail("Present", config.present());
					serverInfo.id = deterministicRandom()->randomUniqueID();
					serverInfo.infoGeneration = ++db->dbInfoCount;
					serverInfo.latencyBandConfig = config;
					db->serverInfo->set(serverInfo);
				}

				state Future<Void> configChangeFuture = tr.watch(latencyBandConfigKey);

				wait(tr.commit());
				wait(configChangeFuture);

				break;
			} catch (Error& e) {
				wait(tr.onError(e));
			}
		}
	}
}

// Monitors the global configuration version key for changes. When changes are
// made, the global configuration history is read and any updates are sent to
// all processes in the system by updating the ClientDBInfo object. The
// GlobalConfig actor class contains the functionality to read the latest
// history and update the processes local view.
ACTOR Future<Void> monitorGlobalConfig(ClusterControllerData::DBInfo* db) {
	loop {
		state ReadYourWritesTransaction tr(db->db);
		loop {
			try {
				tr.setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
				tr.setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);
				state Optional<Value> globalConfigVersion = wait(tr.get(globalConfigVersionKey));
				state ClientDBInfo clientInfo = db->serverInfo->get().client;

				if (globalConfigVersion.present()) {
					// Since the history keys end with versionstamps, they
					// should be sorted correctly (versionstamps are stored in
					// big-endian order).
					RangeResult globalConfigHistory =
					    wait(tr.getRange(globalConfigHistoryKeys, CLIENT_KNOBS->TOO_MANY));
					// If the global configuration version key has been set,
					// the history should contain at least one item.
					ASSERT(globalConfigHistory.size() > 0);
					clientInfo.history.clear();

					for (const auto& kv : globalConfigHistory) {
						ObjectReader reader(kv.value.begin(), IncludeVersion());
						if (reader.protocolVersion() != g_network->protocolVersion()) {
							// If the protocol version has changed, the
							// GlobalConfig actor should refresh its view by
							// reading the entire global configuration key
							// range.  Setting the version to the max int64_t
							// will always cause the global configuration
							// updater to refresh its view of the configuration
							// keyspace.
							clientInfo.history.clear();
							clientInfo.history.emplace_back(std::numeric_limits<Version>::max());
							break;
						}

						VersionHistory vh;
						reader.deserialize(vh);

						// Read commit version out of versionstamp at end of key.
						BinaryReader versionReader =
						    BinaryReader(kv.key.removePrefix(globalConfigHistoryPrefix), Unversioned());
						Version historyCommitVersion;
						versionReader >> historyCommitVersion;
						historyCommitVersion = bigEndian64(historyCommitVersion);
						vh.version = historyCommitVersion;

						clientInfo.history.push_back(std::move(vh));
					}

					if (clientInfo.history.size() > 0) {
						// The first item in the historical list of mutations
						// is only used to:
						//   a) Recognize that some historical changes may have
						//      been missed, and the entire global
						//      configuration keyspace needs to be read, or..
						//   b) Check which historical updates have already
						//      been applied. If this is the case, the first
						//      history item must have a version greater than
						//      or equal to whatever version the global
						//      configuration was last updated at, and
						//      therefore won't need to be applied again.
						clientInfo.history[0].mutations = Standalone<VectorRef<MutationRef>>();
					}

					clientInfo.id = deterministicRandom()->randomUniqueID();
					// Update ServerDBInfo so fdbserver processes receive updated history.
					ServerDBInfo serverInfo = db->serverInfo->get();
					serverInfo.id = deterministicRandom()->randomUniqueID();
					serverInfo.infoGeneration = ++db->dbInfoCount;
					serverInfo.client = clientInfo;
					db->serverInfo->set(serverInfo);

					// Update ClientDBInfo so client processes receive updated history.
					db->clientInfo->set(clientInfo);
				}

				state Future<Void> globalConfigFuture = tr.watch(globalConfigVersionKey);
				wait(tr.commit());
				wait(globalConfigFuture);
				break;
			} catch (Error& e) {
				wait(tr.onError(e));
			}
		}
	}
}

ACTOR Future<Void> updatedChangingDatacenters(ClusterControllerData* self) {
	// do not change the cluster controller until all the processes have had a chance to register
	wait(delay(SERVER_KNOBS->WAIT_FOR_GOOD_RECRUITMENT_DELAY));
	loop {
		state Future<Void> onChange = self->desiredDcIds.onChange();
		if (!self->desiredDcIds.get().present()) {
			self->changingDcIds.set(std::make_pair(false, self->desiredDcIds.get()));
		} else {
			auto& worker = self->id_worker[self->clusterControllerProcessId];
			uint8_t newFitness = ClusterControllerPriorityInfo::calculateDCFitness(
			    worker.details.interf.locality.dcId(), self->desiredDcIds.get().get());
			self->changingDcIds.set(
			    std::make_pair(worker.priorityInfo.dcFitness > newFitness, self->desiredDcIds.get()));

			TraceEvent("UpdateChangingDatacenter", self->id)
			    .detail("OldFitness", worker.priorityInfo.dcFitness)
			    .detail("NewFitness", newFitness);
			if (worker.priorityInfo.dcFitness > newFitness) {
				worker.priorityInfo.dcFitness = newFitness;
				if (!worker.reply.isSet()) {
					worker.reply.send(RegisterWorkerReply(worker.details.processClass, worker.priorityInfo));
				}
			} else {
				state int currentFit = ProcessClass::BestFit;
				while (currentFit <= ProcessClass::NeverAssign) {
					bool updated = false;
					for (auto& it : self->id_worker) {
						if ((!it.second.priorityInfo.isExcluded &&
						     it.second.priorityInfo.processClassFitness == currentFit) ||
						    currentFit == ProcessClass::NeverAssign) {
							uint8_t fitness = ClusterControllerPriorityInfo::calculateDCFitness(
							    it.second.details.interf.locality.dcId(), self->changingDcIds.get().second.get());
							if (it.first != self->clusterControllerProcessId &&
							    it.second.priorityInfo.dcFitness != fitness) {
								updated = true;
								it.second.priorityInfo.dcFitness = fitness;
								if (!it.second.reply.isSet()) {
									it.second.reply.send(
									    RegisterWorkerReply(it.second.details.processClass, it.second.priorityInfo));
								}
							}
						}
					}
					if (updated && currentFit < ProcessClass::NeverAssign) {
						wait(delay(SERVER_KNOBS->CC_CLASS_DELAY));
					}
					currentFit++;
				}
			}
		}

		wait(onChange);
	}
}

ACTOR Future<Void> updatedChangedDatacenters(ClusterControllerData* self) {
	state Future<Void> changeDelay = delay(SERVER_KNOBS->CC_CHANGE_DELAY);
	state Future<Void> onChange = self->changingDcIds.onChange();
	loop {
		choose {
			when(wait(onChange)) {
				changeDelay = delay(SERVER_KNOBS->CC_CHANGE_DELAY);
				onChange = self->changingDcIds.onChange();
			}
			when(wait(changeDelay)) {
				changeDelay = Never();
				onChange = self->changingDcIds.onChange();

				self->changedDcIds.set(self->changingDcIds.get());
				if (self->changedDcIds.get().second.present()) {
					TraceEvent("UpdateChangedDatacenter", self->id).detail("CCFirst", self->changedDcIds.get().first);
					if (!self->changedDcIds.get().first) {
						auto& worker = self->id_worker[self->clusterControllerProcessId];
						uint8_t newFitness = ClusterControllerPriorityInfo::calculateDCFitness(
						    worker.details.interf.locality.dcId(), self->changedDcIds.get().second.get());
						if (worker.priorityInfo.dcFitness != newFitness) {
							worker.priorityInfo.dcFitness = newFitness;
							if (!worker.reply.isSet()) {
								worker.reply.send(
								    RegisterWorkerReply(worker.details.processClass, worker.priorityInfo));
							}
						}
					} else {
						state int currentFit = ProcessClass::BestFit;
						while (currentFit <= ProcessClass::NeverAssign) {
							bool updated = false;
							for (auto& it : self->id_worker) {
								if ((!it.second.priorityInfo.isExcluded &&
								     it.second.priorityInfo.processClassFitness == currentFit) ||
								    currentFit == ProcessClass::NeverAssign) {
									uint8_t fitness = ClusterControllerPriorityInfo::calculateDCFitness(
									    it.second.details.interf.locality.dcId(),
									    self->changedDcIds.get().second.get());
									if (it.first != self->clusterControllerProcessId &&
									    it.second.priorityInfo.dcFitness != fitness) {
										updated = true;
										it.second.priorityInfo.dcFitness = fitness;
										if (!it.second.reply.isSet()) {
											it.second.reply.send(RegisterWorkerReply(it.second.details.processClass,
											                                         it.second.priorityInfo));
										}
									}
								}
							}
							if (updated && currentFit < ProcessClass::NeverAssign) {
								wait(delay(SERVER_KNOBS->CC_CLASS_DELAY));
							}
							currentFit++;
						}
					}
				}
			}
		}
	}
}

ACTOR Future<Void> updateDatacenterVersionDifference(ClusterControllerData* self) {
	state double lastLogTime = 0;
	loop {
		self->versionDifferenceUpdated = false;
		if (self->db.serverInfo->get().recoveryState >= RecoveryState::ACCEPTING_COMMITS &&
		    self->db.config.usableRegions == 1) {
			bool oldDifferenceTooLarge = !self->versionDifferenceUpdated ||
			                             self->datacenterVersionDifference >= SERVER_KNOBS->MAX_VERSION_DIFFERENCE;
			self->versionDifferenceUpdated = true;
			self->datacenterVersionDifference = 0;

			if (oldDifferenceTooLarge) {
				checkOutstandingRequests(self);
			}

			wait(self->db.serverInfo->onChange());
			continue;
		}

		state Optional<TLogInterface> primaryLog;
		state Optional<TLogInterface> remoteLog;
		if (self->db.serverInfo->get().recoveryState >= RecoveryState::ALL_LOGS_RECRUITED) {
			for (auto& logSet : self->db.serverInfo->get().logSystemConfig.tLogs) {
				if (logSet.isLocal && logSet.locality != tagLocalitySatellite) {
					for (auto& tLog : logSet.tLogs) {
						if (tLog.present()) {
							primaryLog = tLog.interf();
							break;
						}
					}
				}
				if (!logSet.isLocal) {
					for (auto& tLog : logSet.tLogs) {
						if (tLog.present()) {
							remoteLog = tLog.interf();
							break;
						}
					}
				}
			}
		}

		if (!primaryLog.present() || !remoteLog.present()) {
			wait(self->db.serverInfo->onChange());
			continue;
		}

		state Future<Void> onChange = self->db.serverInfo->onChange();
		loop {
			state Future<TLogQueuingMetricsReply> primaryMetrics =
			    brokenPromiseToNever(primaryLog.get().getQueuingMetrics.getReply(TLogQueuingMetricsRequest()));
			state Future<TLogQueuingMetricsReply> remoteMetrics =
			    brokenPromiseToNever(remoteLog.get().getQueuingMetrics.getReply(TLogQueuingMetricsRequest()));

			wait((success(primaryMetrics) && success(remoteMetrics)) || onChange);
			if (onChange.isReady()) {
				break;
			}

			if (primaryMetrics.get().v > 0 && remoteMetrics.get().v > 0) {
				bool oldDifferenceTooLarge = !self->versionDifferenceUpdated ||
				                             self->datacenterVersionDifference >= SERVER_KNOBS->MAX_VERSION_DIFFERENCE;
				self->versionDifferenceUpdated = true;
				self->datacenterVersionDifference = primaryMetrics.get().v - remoteMetrics.get().v;

				if (oldDifferenceTooLarge && self->datacenterVersionDifference < SERVER_KNOBS->MAX_VERSION_DIFFERENCE) {
					checkOutstandingRequests(self);
				}

				if (now() - lastLogTime > SERVER_KNOBS->CLUSTER_CONTROLLER_LOGGING_DELAY) {
					lastLogTime = now();
					TraceEvent("DatacenterVersionDifference", self->id)
					    .detail("Difference", self->datacenterVersionDifference);
				}
			}

			wait(delay(SERVER_KNOBS->VERSION_LAG_METRIC_INTERVAL) || onChange);
			if (onChange.isReady()) {
				break;
			}
		}
	}
}

// A background actor that periodically checks remote DC health, and `checkOutstandingRequests` if remote DC
// recovers.
ACTOR Future<Void> updateRemoteDCHealth(ClusterControllerData* self) {
	// The purpose of the initial delay is to wait for the cluster to achieve a steady state before checking remote
	// DC health, since remote DC healthy may trigger a failover, and we don't want that to happen too frequently.
	wait(delay(SERVER_KNOBS->INITIAL_UPDATE_CROSS_DC_INFO_DELAY));

	self->remoteDCMonitorStarted = true;

	// When the remote DC health just start, we may just recover from a health degradation. Check if we can failback
	// if we are currently in the remote DC in the database configuration.
	if (!self->remoteTransactionSystemDegraded) {
		checkOutstandingRequests(self);
	}

	loop {
		bool oldRemoteTransactionSystemDegraded = self->remoteTransactionSystemDegraded;
		self->remoteTransactionSystemDegraded = self->remoteTransactionSystemContainsDegradedServers();

		if (oldRemoteTransactionSystemDegraded && !self->remoteTransactionSystemDegraded) {
			checkOutstandingRequests(self);
		}
		wait(delay(SERVER_KNOBS->CHECK_REMOTE_HEALTH_INTERVAL));
	}
}

ACTOR Future<Void> doEmptyCommit(Database cx) {
	state Transaction tr(cx);
	loop {
		try {
			tr.setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);
			tr.setOption(FDBTransactionOptions::LOCK_AWARE);
			tr.makeSelfConflicting();
			wait(tr.commit());
			return Void();
		} catch (Error& e) {
			wait(tr.onError(e));
		}
	}
}

ACTOR Future<Void> handleForcedRecoveries(ClusterControllerData* self, ClusterControllerFullInterface interf) {
	loop {
		state ForceRecoveryRequest req = waitNext(interf.clientInterface.forceRecovery.getFuture());
		TraceEvent("ForcedRecoveryStart", self->id)
		    .detail("ClusterControllerDcId", self->clusterControllerDcId)
		    .detail("DcId", req.dcId.printable());
		state Future<Void> fCommit = doEmptyCommit(self->cx);
		wait(fCommit || delay(SERVER_KNOBS->FORCE_RECOVERY_CHECK_DELAY));
		if (!fCommit.isReady() || fCommit.isError()) {
			if (self->clusterControllerDcId != req.dcId) {
				std::vector<Optional<Key>> dcPriority;
				dcPriority.push_back(req.dcId);
				dcPriority.push_back(self->clusterControllerDcId);
				self->desiredDcIds.set(dcPriority);
			} else {
				self->db.forceRecovery = true;
				self->db.forceMasterFailure.trigger();
			}
			wait(fCommit);
		}
		TraceEvent("ForcedRecoveryFinish", self->id).log();
		self->db.forceRecovery = false;
		req.reply.send(Void());
	}
}

ACTOR Future<Void> startDataDistributor(ClusterControllerData* self) {
	wait(delay(0.0)); // If master fails at the same time, give it a chance to clear master PID.

	TraceEvent("CCStartDataDistributor", self->id).log();
	loop {
		try {
			state bool noDistributor = !self->db.serverInfo->get().distributor.present();
			while (!self->masterProcessId.present() ||
			       self->masterProcessId != self->db.serverInfo->get().master.locality.processId() ||
			       self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
				wait(self->db.serverInfo->onChange() || delay(SERVER_KNOBS->WAIT_FOR_GOOD_RECRUITMENT_DELAY));
			}
			if (noDistributor && self->db.serverInfo->get().distributor.present()) {
				// Existing distributor registers while waiting, so skip.
				return Void();
			}

			std::map<Optional<Standalone<StringRef>>, int> idUsed = self->getUsedIds();
			WorkerFitnessInfo ddWorker = self->getWorkerForRoleInDatacenter(self->clusterControllerDcId,
			                                                                ProcessClass::DataDistributor,
			                                                                ProcessClass::NeverAssign,
			                                                                self->db.config,
			                                                                idUsed);
			InitializeDataDistributorRequest req(deterministicRandom()->randomUniqueID());
			state WorkerDetails worker = ddWorker.worker;
			if (self->onMasterIsBetter(worker, ProcessClass::DataDistributor)) {
				worker = self->id_worker[self->masterProcessId.get()].details;
			}

			self->recruitingDistributorID = req.reqId;
			TraceEvent("CCRecruitDataDistributor", self->id)
			    .detail("Addr", worker.interf.address())
			    .detail("DDID", req.reqId);

			ErrorOr<DataDistributorInterface> ddInterf = wait(worker.interf.dataDistributor.getReplyUnlessFailedFor(
			    req, SERVER_KNOBS->WAIT_FOR_DISTRIBUTOR_JOIN_DELAY, 0));

			if (ddInterf.present()) {
				self->recruitDistributor.set(false);
				self->recruitingDistributorID = ddInterf.get().id();
				const auto& distributor = self->db.serverInfo->get().distributor;
				TraceEvent("CCDataDistributorRecruited", self->id)
				    .detail("Addr", worker.interf.address())
				    .detail("DDID", ddInterf.get().id());
				if (distributor.present() && distributor.get().id() != ddInterf.get().id() &&
				    self->id_worker.count(distributor.get().locality.processId())) {

					TraceEvent("CCHaltDataDistributorAfterRecruit", self->id)
					    .detail("DDID", distributor.get().id())
					    .detail("DcID", printable(self->clusterControllerDcId));

					DataDistributorSingleton(distributor).halt(self, distributor.get().locality.processId());
				}
				if (!distributor.present() || distributor.get().id() != ddInterf.get().id()) {
					self->db.setDistributor(ddInterf.get());
				}
				checkOutstandingRequests(self);
				return Void();
			}
		} catch (Error& e) {
			TraceEvent("CCDataDistributorRecruitError", self->id).error(e);
			if (e.code() != error_code_no_more_servers) {
				throw;
			}
		}
		wait(lowPriorityDelay(SERVER_KNOBS->ATTEMPT_RECRUITMENT_DELAY));
	}
}

ACTOR Future<Void> monitorDataDistributor(ClusterControllerData* self) {
	while (self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
		wait(self->db.serverInfo->onChange());
	}

	loop {
		if (self->db.serverInfo->get().distributor.present() && !self->recruitDistributor.get()) {
			choose {
				when(wait(waitFailureClient(self->db.serverInfo->get().distributor.get().waitFailure,
				                            SERVER_KNOBS->DD_FAILURE_TIME))) {
					TraceEvent("CCDataDistributorDied", self->id)
					    .detail("DDID", self->db.serverInfo->get().distributor.get().id());
					self->db.clearInterf(ProcessClass::DataDistributorClass);
				}
				when(wait(self->recruitDistributor.onChange())) {}
			}
		} else {
			wait(startDataDistributor(self));
		}
	}
}

ACTOR Future<Void> startRatekeeper(ClusterControllerData* self) {
	wait(delay(0.0)); // If master fails at the same time, give it a chance to clear master PID.

	TraceEvent("CCStartRatekeeper", self->id).log();
	loop {
		try {
			state bool no_ratekeeper = !self->db.serverInfo->get().ratekeeper.present();
			while (!self->masterProcessId.present() ||
			       self->masterProcessId != self->db.serverInfo->get().master.locality.processId() ||
			       self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
				wait(self->db.serverInfo->onChange() || delay(SERVER_KNOBS->WAIT_FOR_GOOD_RECRUITMENT_DELAY));
			}
			if (no_ratekeeper && self->db.serverInfo->get().ratekeeper.present()) {
				// Existing ratekeeper registers while waiting, so skip.
				return Void();
			}

			std::map<Optional<Standalone<StringRef>>, int> id_used = self->getUsedIds();
			WorkerFitnessInfo rkWorker = self->getWorkerForRoleInDatacenter(self->clusterControllerDcId,
			                                                                ProcessClass::Ratekeeper,
			                                                                ProcessClass::NeverAssign,
			                                                                self->db.config,
			                                                                id_used);
			InitializeRatekeeperRequest req(deterministicRandom()->randomUniqueID());
			state WorkerDetails worker = rkWorker.worker;
			if (self->onMasterIsBetter(worker, ProcessClass::Ratekeeper)) {
				worker = self->id_worker[self->masterProcessId.get()].details;
			}

			self->recruitingRatekeeperID = req.reqId;
			TraceEvent("CCRecruitRatekeeper", self->id)
			    .detail("Addr", worker.interf.address())
			    .detail("RKID", req.reqId);

			ErrorOr<RatekeeperInterface> interf = wait(
			    worker.interf.ratekeeper.getReplyUnlessFailedFor(req, SERVER_KNOBS->WAIT_FOR_RATEKEEPER_JOIN_DELAY, 0));
			if (interf.present()) {
				self->recruitRatekeeper.set(false);
				self->recruitingRatekeeperID = interf.get().id();
				const auto& ratekeeper = self->db.serverInfo->get().ratekeeper;
				TraceEvent("CCRatekeeperRecruited", self->id)
				    .detail("Addr", worker.interf.address())
				    .detail("RKID", interf.get().id());
				if (ratekeeper.present() && ratekeeper.get().id() != interf.get().id() &&
				    self->id_worker.count(ratekeeper.get().locality.processId())) {
					TraceEvent("CCHaltRatekeeperAfterRecruit", self->id)
					    .detail("RKID", ratekeeper.get().id())
					    .detail("DcID", printable(self->clusterControllerDcId));
					RatekeeperSingleton(ratekeeper).halt(self, ratekeeper.get().locality.processId());
				}
				if (!ratekeeper.present() || ratekeeper.get().id() != interf.get().id()) {
					self->db.setRatekeeper(interf.get());
				}
				checkOutstandingRequests(self);
				return Void();
			}
		} catch (Error& e) {
			TraceEvent("CCRatekeeperRecruitError", self->id).error(e);
			if (e.code() != error_code_no_more_servers) {
				throw;
			}
		}
		wait(lowPriorityDelay(SERVER_KNOBS->ATTEMPT_RECRUITMENT_DELAY));
	}
}

ACTOR Future<Void> monitorRatekeeper(ClusterControllerData* self) {
	while (self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
		wait(self->db.serverInfo->onChange());
	}

	loop {
		if (self->db.serverInfo->get().ratekeeper.present() && !self->recruitRatekeeper.get()) {
			choose {
				when(wait(waitFailureClient(self->db.serverInfo->get().ratekeeper.get().waitFailure,
				                            SERVER_KNOBS->RATEKEEPER_FAILURE_TIME))) {
					TraceEvent("CCRatekeeperDied", self->id)
					    .detail("RKID", self->db.serverInfo->get().ratekeeper.get().id());
					self->db.clearInterf(ProcessClass::RatekeeperClass);
				}
				when(wait(self->recruitRatekeeper.onChange())) {}
			}
		} else {
			wait(startRatekeeper(self));
		}
	}
}

// Acquires the BM lock by getting the next epoch no.
ACTOR Future<int64_t> getNextBMEpoch(ClusterControllerData* self) {
	state Reference<ReadYourWritesTransaction> tr = makeReference<ReadYourWritesTransaction>(self->cx);

	loop {
		tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
		tr->setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);
		try {
			Optional<Value> oldEpoch = wait(tr->get(blobManagerEpochKey));
			state int64_t newEpoch = oldEpoch.present() ? decodeBlobManagerEpochValue(oldEpoch.get()) + 1 : 1;
			tr->set(blobManagerEpochKey, blobManagerEpochValueFor(newEpoch));

			wait(tr->commit());
			return newEpoch;
		} catch (Error& e) {
			wait(tr->onError(e));
		}
	}
}

ACTOR Future<Void> startEncryptKeyProxy(ClusterControllerData* self) {
	wait(delay(0.0)); // If master fails at the same time, give it a chance to clear master PID.

	TraceEvent("CCEKP_Start", self->id).log();
	loop {
		try {
			// EncryptKeyServer interface is critical in recovering tlog encrypted transactions,
			// hence, the process only waits for the master recruitment and not the full cluster recovery.
			state bool noEncryptKeyServer = !self->db.serverInfo->get().encryptKeyProxy.present();
			while (!self->masterProcessId.present() ||
			       self->masterProcessId != self->db.serverInfo->get().master.locality.processId() ||
			       self->db.serverInfo->get().recoveryState < RecoveryState::LOCKING_CSTATE) {
				wait(self->db.serverInfo->onChange() || delay(SERVER_KNOBS->WAIT_FOR_GOOD_RECRUITMENT_DELAY));
			}
			if (noEncryptKeyServer && self->db.serverInfo->get().encryptKeyProxy.present()) {
				// Existing encryptKeyServer registers while waiting, so skip.
				return Void();
			}

			// Recruit EncryptKeyProxy in the same datacenter as the ClusterController.
			// This should always be possible, given EncryptKeyProxy is stateless, we can recruit EncryptKeyProxy
			// on the same process as the CluserController.
			state std::map<Optional<Standalone<StringRef>>, int> id_used;
			self->updateKnownIds(&id_used);
			state WorkerFitnessInfo ekpWorker = self->getWorkerForRoleInDatacenter(self->clusterControllerDcId,
			                                                                       ProcessClass::EncryptKeyProxy,
			                                                                       ProcessClass::NeverAssign,
			                                                                       self->db.config,
			                                                                       id_used);

			InitializeEncryptKeyProxyRequest req(deterministicRandom()->randomUniqueID());
			state WorkerDetails worker = ekpWorker.worker;
			if (self->onMasterIsBetter(worker, ProcessClass::EncryptKeyProxy)) {
				worker = self->id_worker[self->masterProcessId.get()].details;
			}

			self->recruitingEncryptKeyProxyID = req.reqId;
			TraceEvent("CCEKP_Recruit", self->id).detail("Addr", worker.interf.address()).detail("Id", req.reqId);

			ErrorOr<EncryptKeyProxyInterface> interf = wait(worker.interf.encryptKeyProxy.getReplyUnlessFailedFor(
			    req, SERVER_KNOBS->WAIT_FOR_ENCRYPT_KEY_PROXY_JOIN_DELAY, 0));
			if (interf.present()) {
				self->recruitEncryptKeyProxy.set(false);
				self->recruitingEncryptKeyProxyID = interf.get().id();
				const auto& encryptKeyProxy = self->db.serverInfo->get().encryptKeyProxy;
				TraceEvent("CCEKP_Recruited", self->id)
				    .detail("Addr", worker.interf.address())
				    .detail("Id", interf.get().id())
				    .detail("ProcessId", interf.get().locality.processId());
				if (encryptKeyProxy.present() && encryptKeyProxy.get().id() != interf.get().id() &&
				    self->id_worker.count(encryptKeyProxy.get().locality.processId())) {
					TraceEvent("CCEKP_HaltAfterRecruit", self->id)
					    .detail("Id", encryptKeyProxy.get().id())
					    .detail("DcId", printable(self->clusterControllerDcId));
					EncryptKeyProxySingleton(encryptKeyProxy).halt(self, encryptKeyProxy.get().locality.processId());
				}
				if (!encryptKeyProxy.present() || encryptKeyProxy.get().id() != interf.get().id()) {
					self->db.setEncryptKeyProxy(interf.get());
					TraceEvent("CCEKP_UpdateInf", self->id)
					    .detail("Id", self->db.serverInfo->get().encryptKeyProxy.get().id());
				}
				return Void();
			}
		} catch (Error& e) {
			TraceEvent("CCEKP_RecruitError", self->id).error(e);
			if (e.code() != error_code_no_more_servers) {
				throw;
			}
		}
		wait(lowPriorityDelay(SERVER_KNOBS->ATTEMPT_RECRUITMENT_DELAY));
	}
}

ACTOR Future<Void> monitorEncryptKeyProxy(ClusterControllerData* self) {
	loop {
		if (self->db.serverInfo->get().encryptKeyProxy.present() && !self->recruitEncryptKeyProxy.get()) {
			choose {
				when(wait(waitFailureClient(self->db.serverInfo->get().encryptKeyProxy.get().waitFailure,
				                            SERVER_KNOBS->ENCRYPT_KEY_PROXY_FAILURE_TIME))) {
					TraceEvent("CCEKP_Died", self->id);
					self->db.clearInterf(ProcessClass::EncryptKeyProxyClass);
				}
				when(wait(self->recruitEncryptKeyProxy.onChange())) {}
			}
		} else {
			wait(startEncryptKeyProxy(self));
		}
	}
}

ACTOR Future<Void> startBlobManager(ClusterControllerData* self) {
	wait(delay(0.0)); // If master fails at the same time, give it a chance to clear master PID.

	TraceEvent("CCStartBlobManager", self->id).log();
	loop {
		try {
			state bool noBlobManager = !self->db.serverInfo->get().blobManager.present();
			while (!self->masterProcessId.present() ||
			       self->masterProcessId != self->db.serverInfo->get().master.locality.processId() ||
			       self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
				wait(self->db.serverInfo->onChange() || delay(SERVER_KNOBS->WAIT_FOR_GOOD_RECRUITMENT_DELAY));
			}
			if (noBlobManager && self->db.serverInfo->get().blobManager.present()) {
				// Existing blob manager registers while waiting, so skip.
				return Void();
			}

			state std::map<Optional<Standalone<StringRef>>, int> id_used = self->getUsedIds();
			state WorkerFitnessInfo bmWorker = self->getWorkerForRoleInDatacenter(self->clusterControllerDcId,
			                                                                      ProcessClass::BlobManager,
			                                                                      ProcessClass::NeverAssign,
			                                                                      self->db.config,
			                                                                      id_used);

			int64_t nextEpoch = wait(getNextBMEpoch(self));
			if (!self->masterProcessId.present() ||
			    self->masterProcessId != self->db.serverInfo->get().master.locality.processId() ||
			    self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
				continue;
			}
			InitializeBlobManagerRequest req(deterministicRandom()->randomUniqueID(), nextEpoch);
			state WorkerDetails worker = bmWorker.worker;
			if (self->onMasterIsBetter(worker, ProcessClass::BlobManager)) {
				worker = self->id_worker[self->masterProcessId.get()].details;
			}

			self->recruitingBlobManagerID = req.reqId;
			TraceEvent("CCRecruitBlobManager", self->id)
			    .detail("Addr", worker.interf.address())
			    .detail("BMID", req.reqId);

			ErrorOr<BlobManagerInterface> interf = wait(worker.interf.blobManager.getReplyUnlessFailedFor(
			    req, SERVER_KNOBS->WAIT_FOR_BLOB_MANAGER_JOIN_DELAY, 0));
			if (interf.present()) {
				self->recruitBlobManager.set(false);
				self->recruitingBlobManagerID = interf.get().id();
				const auto& blobManager = self->db.serverInfo->get().blobManager;
				TraceEvent("CCBlobManagerRecruited", self->id)
				    .detail("Addr", worker.interf.address())
				    .detail("BMID", interf.get().id());
				if (blobManager.present() && blobManager.get().id() != interf.get().id() &&
				    self->id_worker.count(blobManager.get().locality.processId())) {
					TraceEvent("CCHaltBlobManagerAfterRecruit", self->id)
					    .detail("BMID", blobManager.get().id())
					    .detail("DcID", printable(self->clusterControllerDcId));
					BlobManagerSingleton(blobManager).halt(self, blobManager.get().locality.processId());
				}
				if (!blobManager.present() || blobManager.get().id() != interf.get().id()) {
					self->db.setBlobManager(interf.get());
				}
				checkOutstandingRequests(self);
				return Void();
			}
		} catch (Error& e) {
			TraceEvent("CCBlobManagerRecruitError", self->id).error(e);
			if (e.code() != error_code_no_more_servers) {
				throw;
			}
		}
		wait(lowPriorityDelay(SERVER_KNOBS->ATTEMPT_RECRUITMENT_DELAY));
	}
}

ACTOR Future<Void> watchBlobGranulesConfigKey(ClusterControllerData* self) {
	state Reference<ReadYourWritesTransaction> tr = makeReference<ReadYourWritesTransaction>(self->cx);
	state Key blobGranuleConfigKey = configKeysPrefix.withSuffix("blob_granules_enabled"_sr);

	loop {
		try {
			tr->reset();
			tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
			tr->setOption(FDBTransactionOptions::PRIORITY_SYSTEM_IMMEDIATE);

			Optional<Value> blobConfig = wait(tr->get(blobGranuleConfigKey));
			if (blobConfig.present()) {
				self->db.blobGranulesEnabled.set(blobConfig.get() == LiteralStringRef("1"));
			}

			state Future<Void> watch = tr->watch(blobGranuleConfigKey);
			wait(tr->commit());
			wait(watch);
		} catch (Error& e) {
			wait(tr->onError(e));
		}
	}
}

ACTOR Future<Void> monitorBlobManager(ClusterControllerData* self) {
	while (self->db.serverInfo->get().recoveryState < RecoveryState::ACCEPTING_COMMITS) {
		wait(self->db.serverInfo->onChange());
	}

	loop {
		if (self->db.serverInfo->get().blobManager.present() && !self->recruitBlobManager.get()) {
			state Future<Void> wfClient = waitFailureClient(self->db.serverInfo->get().blobManager.get().waitFailure,
			                                                SERVER_KNOBS->BLOB_MANAGER_FAILURE_TIME);
			loop {
				choose {
					when(wait(wfClient)) {
						TraceEvent("CCBlobManagerDied", self->id)
						    .detail("BMID", self->db.serverInfo->get().blobManager.get().id());
						self->db.clearInterf(ProcessClass::BlobManagerClass);
						break;
					}
					when(wait(self->recruitBlobManager.onChange())) { break; }
					when(wait(self->db.blobGranulesEnabled.onChange())) {
						// if there is a blob manager present but blob granules are now disabled, stop the BM
						if (!self->db.blobGranulesEnabled.get()) {
							const auto& blobManager = self->db.serverInfo->get().blobManager;
							BlobManagerSingleton(blobManager)
							    .haltBlobGranules(self, blobManager.get().locality.processId());
							break;
						}
					}
				}
			}
		} else if (self->db.blobGranulesEnabled.get()) {
			// if there is no blob manager present but blob granules are now enabled, recruit a BM
			wait(startBlobManager(self));
		} else {
			// if there is no blob manager present and blob granules are disabled, wait for a config change
			wait(self->db.blobGranulesEnabled.onChange());
		}
	}
}

ACTOR Future<Void> dbInfoUpdater(ClusterControllerData* self) {
	state Future<Void> dbInfoChange = self->db.serverInfo->onChange();
	state Future<Void> updateDBInfo = self->updateDBInfo.onTrigger();
	loop {
		choose {
			when(wait(updateDBInfo)) { wait(delay(SERVER_KNOBS->DBINFO_BATCH_DELAY) || dbInfoChange); }
			when(wait(dbInfoChange)) {}
		}

		UpdateServerDBInfoRequest req;
		if (dbInfoChange.isReady()) {
			for (auto& it : self->id_worker) {
				req.broadcastInfo.push_back(it.second.details.interf.updateServerDBInfo.getEndpoint());
			}
		} else {
			for (auto it : self->removedDBInfoEndpoints) {
				self->updateDBInfoEndpoints.erase(it);
			}
			req.broadcastInfo =
			    std::vector<Endpoint>(self->updateDBInfoEndpoints.begin(), self->updateDBInfoEndpoints.end());
		}

		self->updateDBInfoEndpoints.clear();
		self->removedDBInfoEndpoints.clear();

		dbInfoChange = self->db.serverInfo->onChange();
		updateDBInfo = self->updateDBInfo.onTrigger();

		req.serializedDbInfo =
		    BinaryWriter::toValue(self->db.serverInfo->get(), AssumeVersion(g_network->protocolVersion()));

		TraceEvent("DBInfoStartBroadcast", self->id).log();
		choose {
			when(std::vector<Endpoint> notUpdated =
			         wait(broadcastDBInfoRequest(req, SERVER_KNOBS->DBINFO_SEND_AMOUNT, Optional<Endpoint>(), false))) {
				TraceEvent("DBInfoFinishBroadcast", self->id).detail("NotUpdated", notUpdated.size());
				if (notUpdated.size()) {
					self->updateDBInfoEndpoints.insert(notUpdated.begin(), notUpdated.end());
					self->updateDBInfo.trigger();
				}
			}
			when(wait(dbInfoChange)) {}
		}
	}
}

// The actor that periodically monitors the health of tracked workers.
ACTOR Future<Void> workerHealthMonitor(ClusterControllerData* self) {
	loop {
		try {
			while (!self->goodRecruitmentTime.isReady()) {
				wait(lowPriorityDelay(SERVER_KNOBS->CC_WORKER_HEALTH_CHECKING_INTERVAL));
			}

			self->degradedServers = self->getServersWithDegradedLink();

			// Compare `self->degradedServers` with `self->excludedDegradedServers` and remove those that have
			// recovered.
			for (auto it = self->excludedDegradedServers.begin(); it != self->excludedDegradedServers.end();) {
				if (self->degradedServers.find(*it) == self->degradedServers.end()) {
					self->excludedDegradedServers.erase(it++);
				} else {
					++it;
				}
			}

			if (!self->degradedServers.empty()) {
				std::string degradedServerString;
				for (const auto& server : self->degradedServers) {
					degradedServerString += server.toString() + " ";
				}
				TraceEvent("ClusterControllerHealthMonitor").detail("DegradedServers", degradedServerString);

				// Check if the cluster controller should trigger a recovery to exclude any degraded servers from
				// the transaction system.
				if (self->shouldTriggerRecoveryDueToDegradedServers()) {
					if (SERVER_KNOBS->CC_HEALTH_TRIGGER_RECOVERY) {
						if (self->recentRecoveryCountDueToHealth() < SERVER_KNOBS->CC_MAX_HEALTH_RECOVERY_COUNT) {
							self->recentHealthTriggeredRecoveryTime.push(now());
							self->excludedDegradedServers = self->degradedServers;
							TraceEvent("DegradedServerDetectedAndTriggerRecovery")
							    .detail("RecentRecoveryCountDueToHealth", self->recentRecoveryCountDueToHealth());
							self->db.forceMasterFailure.trigger();
						}
					} else {
						self->excludedDegradedServers.clear();
						TraceEvent("DegradedServerDetectedAndSuggestRecovery").log();
					}
				} else if (self->shouldTriggerFailoverDueToDegradedServers()) {
					double ccUpTime = now() - machineStartTime();
					if (SERVER_KNOBS->CC_HEALTH_TRIGGER_FAILOVER &&
					    ccUpTime > SERVER_KNOBS->INITIAL_UPDATE_CROSS_DC_INFO_DELAY) {
						TraceEvent("DegradedServerDetectedAndTriggerFailover").log();
						std::vector<Optional<Key>> dcPriority;
						auto remoteDcId = self->db.config.regions[0].dcId == self->clusterControllerDcId.get()
						                      ? self->db.config.regions[1].dcId
						                      : self->db.config.regions[0].dcId;

						// Switch the current primary DC and remote DC in desiredDcIds, so that the remote DC
						// becomes the new primary, and the primary DC becomes the new remote.
						dcPriority.push_back(remoteDcId);
						dcPriority.push_back(self->clusterControllerDcId);
						self->desiredDcIds.set(dcPriority);
					} else {
						TraceEvent("DegradedServerDetectedAndSuggestFailover").detail("CCUpTime", ccUpTime);
					}
				}
			}

			wait(delay(SERVER_KNOBS->CC_WORKER_HEALTH_CHECKING_INTERVAL));
		} catch (Error& e) {
			TraceEvent(SevWarnAlways, "ClusterControllerHealthMonitorError").error(e);
			if (e.code() == error_code_actor_cancelled) {
				throw;
			}
		}
	}
}

ACTOR Future<Void> clusterControllerCore(ClusterControllerFullInterface interf,
                                         Future<Void> leaderFail,
                                         ServerCoordinators coordinators,
                                         LocalityData locality,
                                         ConfigDBType configDBType) {
	state ClusterControllerData self(interf, locality, coordinators);
	state ConfigBroadcaster configBroadcaster(coordinators, configDBType);
	state Future<Void> coordinationPingDelay = delay(SERVER_KNOBS->WORKER_COORDINATION_PING_DELAY);
	state uint64_t step = 0;
	state Future<ErrorOr<Void>> error = errorOr(actorCollection(self.addActor.getFuture()));

	// EncryptKeyProxy is necessary for TLog recovery, recruit it as the first process
	if (SERVER_KNOBS->ENABLE_ENCRYPT_KEY_PROXY) {
		self.addActor.send(monitorEncryptKeyProxy(&self));
	}
	self.addActor.send(clusterWatchDatabase(&self, &self.db, coordinators, leaderFail)); // Start the master database
	self.addActor.send(self.updateWorkerList.init(self.db.db));
	self.addActor.send(statusServer(interf.clientInterface.databaseStatus.getFuture(),
	                                &self,
	                                coordinators,
	                                (configDBType == ConfigDBType::DISABLED) ? nullptr : &configBroadcaster));
	self.addActor.send(timeKeeper(&self));
	self.addActor.send(monitorProcessClasses(&self));
	self.addActor.send(monitorServerInfoConfig(&self.db));
	self.addActor.send(monitorGlobalConfig(&self.db));
	self.addActor.send(updatedChangingDatacenters(&self));
	self.addActor.send(updatedChangedDatacenters(&self));
	self.addActor.send(updateDatacenterVersionDifference(&self));
	self.addActor.send(handleForcedRecoveries(&self, interf));
	self.addActor.send(monitorDataDistributor(&self));
	self.addActor.send(monitorRatekeeper(&self));
	self.addActor.send(monitorBlobManager(&self));
	self.addActor.send(watchBlobGranulesConfigKey(&self));
	self.addActor.send(dbInfoUpdater(&self));
	self.addActor.send(traceCounters("ClusterControllerMetrics",
	                                 self.id,
	                                 SERVER_KNOBS->STORAGE_LOGGING_DELAY,
	                                 &self.clusterControllerMetrics,
	                                 self.id.toString() + "/ClusterControllerMetrics"));
	self.addActor.send(traceRole(Role::CLUSTER_CONTROLLER, interf.id()));
	// printf("%s: I am the cluster controller\n", g_network->getLocalAddress().toString().c_str());

	if (SERVER_KNOBS->CC_ENABLE_WORKER_HEALTH_MONITOR) {
		self.addActor.send(workerHealthMonitor(&self));
		self.addActor.send(updateRemoteDCHealth(&self));
	}

	loop choose {
		when(ErrorOr<Void> err = wait(error)) {
			if (err.isError() && err.getError().code() != error_code_restart_cluster_controller) {
				endRole(Role::CLUSTER_CONTROLLER, interf.id(), "Stop Received Error", false, err.getError());
			} else {
				endRole(Role::CLUSTER_CONTROLLER, interf.id(), "Stop Received Signal", true);
			}

			// We shut down normally even if there was a serious error (so this fdbserver may be re-elected cluster
			// controller)
			return Void();
		}
		when(OpenDatabaseRequest req = waitNext(interf.clientInterface.openDatabase.getFuture())) {
			++self.openDatabaseRequests;
			self.addActor.send(clusterOpenDatabase(&self.db, req));
		}
		when(RecruitStorageRequest req = waitNext(interf.recruitStorage.getFuture())) {
			clusterRecruitStorage(&self, req);
		}
		when(RecruitBlobWorkerRequest req = waitNext(interf.recruitBlobWorker.getFuture())) {
			clusterRecruitBlobWorker(&self, req);
		}
		when(RegisterWorkerRequest req = waitNext(interf.registerWorker.getFuture())) {
			++self.registerWorkerRequests;
			registerWorker(
			    req, &self, coordinators, (configDBType == ConfigDBType::DISABLED) ? nullptr : &configBroadcaster);
		}
		when(GetWorkersRequest req = waitNext(interf.getWorkers.getFuture())) {
			++self.getWorkersRequests;
			std::vector<WorkerDetails> workers;

			for (auto const& [id, worker] : self.id_worker) {
				if ((req.flags & GetWorkersRequest::NON_EXCLUDED_PROCESSES_ONLY) &&
				    self.db.config.isExcludedServer(worker.details.interf.addresses())) {
					continue;
				}

				if ((req.flags & GetWorkersRequest::TESTER_CLASS_ONLY) &&
				    worker.details.processClass.classType() != ProcessClass::TesterClass) {
					continue;
				}

				workers.push_back(worker.details);
			}

			req.reply.send(workers);
		}
		when(GetClientWorkersRequest req = waitNext(interf.clientInterface.getClientWorkers.getFuture())) {
			++self.getClientWorkersRequests;
			std::vector<ClientWorkerInterface> workers;
			for (auto& it : self.id_worker) {
				if (it.second.details.processClass.classType() != ProcessClass::TesterClass) {
					workers.push_back(it.second.details.interf.clientInterface);
				}
			}
			req.reply.send(workers);
		}
		when(wait(coordinationPingDelay)) {
			CoordinationPingMessage message(self.id, step++);
			for (auto& it : self.id_worker)
				it.second.details.interf.coordinationPing.send(message);
			coordinationPingDelay = delay(SERVER_KNOBS->WORKER_COORDINATION_PING_DELAY);
			TraceEvent("CoordinationPingSent", self.id).detail("TimeStep", message.timeStep);
		}
		when(RegisterMasterRequest req = waitNext(interf.registerMaster.getFuture())) {
			++self.registerMasterRequests;
			clusterRegisterMaster(&self, req);
		}
		when(UpdateWorkerHealthRequest req = waitNext(interf.updateWorkerHealth.getFuture())) {
			if (SERVER_KNOBS->CC_ENABLE_WORKER_HEALTH_MONITOR) {
				self.updateWorkerHealth(req);
			}
		}
		when(GetServerDBInfoRequest req = waitNext(interf.getServerDBInfo.getFuture())) {
			self.addActor.send(clusterGetServerInfo(&self.db, req.knownServerInfoID, req.reply));
		}
		when(ReplyPromise<Void> ping = waitNext(interf.clientInterface.ping.getFuture())) { ping.send(Void()); }
	}
}

ACTOR Future<Void> replaceInterface(ClusterControllerFullInterface interf) {
	loop {
		if (interf.hasMessage()) {
			wait(delay(SERVER_KNOBS->REPLACE_INTERFACE_DELAY));
			return Void();
		}
		wait(delay(SERVER_KNOBS->REPLACE_INTERFACE_CHECK_DELAY));
	}
}

ACTOR Future<Void> clusterController(ServerCoordinators coordinators,
                                     Reference<AsyncVar<Optional<ClusterControllerFullInterface>>> currentCC,
                                     bool hasConnected,
                                     Reference<AsyncVar<ClusterControllerPriorityInfo>> asyncPriorityInfo,
                                     LocalityData locality,
                                     ConfigDBType configDBType) {
	loop {
		state ClusterControllerFullInterface cci;
		state bool inRole = false;
		cci.initEndpoints();
		try {
			// Register as a possible leader; wait to be elected
			state Future<Void> leaderFail =
			    tryBecomeLeader(coordinators, cci, currentCC, hasConnected, asyncPriorityInfo);
			state Future<Void> shouldReplace = replaceInterface(cci);

			while (!currentCC->get().present() || currentCC->get().get() != cci) {
				choose {
					when(wait(currentCC->onChange())) {}
					when(wait(leaderFail)) {
						ASSERT(false);
						throw internal_error();
					}
					when(wait(shouldReplace)) { break; }
				}
			}
			if (!shouldReplace.isReady()) {
				shouldReplace = Future<Void>();
				hasConnected = true;
				startRole(Role::CLUSTER_CONTROLLER, cci.id(), UID());
				inRole = true;

				wait(clusterControllerCore(cci, leaderFail, coordinators, locality, configDBType));
			}
		} catch (Error& e) {
			if (inRole)
				endRole(Role::CLUSTER_CONTROLLER,
				        cci.id(),
				        "Error",
				        e.code() == error_code_actor_cancelled || e.code() == error_code_coordinators_changed,
				        e);
			else
				TraceEvent(e.code() == error_code_coordinators_changed ? SevInfo : SevError,
				           "ClusterControllerCandidateError",
				           cci.id())
				    .error(e);
			throw;
		}
	}
}

ACTOR Future<Void> clusterController(Reference<IClusterConnectionRecord> connRecord,
                                     Reference<AsyncVar<Optional<ClusterControllerFullInterface>>> currentCC,
                                     Reference<AsyncVar<ClusterControllerPriorityInfo>> asyncPriorityInfo,
                                     Future<Void> recoveredDiskFiles,
                                     LocalityData locality,
                                     ConfigDBType configDBType) {
	wait(recoveredDiskFiles);
	state bool hasConnected = false;
	loop {
		try {
			wait(connRecord->resolveHostnames());
			ServerCoordinators coordinators(connRecord);
			wait(clusterController(coordinators, currentCC, hasConnected, asyncPriorityInfo, locality, configDBType));
		} catch (Error& e) {
			if (e.code() != error_code_coordinators_changed)
				throw; // Expected to terminate fdbserver
		}

		hasConnected = true;
	}
}

namespace {

// Tests `ClusterControllerData::updateWorkerHealth()` can update `ClusterControllerData::workerHealth` based on
// `UpdateWorkerHealth` request correctly.
TEST_CASE("/fdbserver/clustercontroller/updateWorkerHealth") {
	// Create a testing ClusterControllerData. Most of the internal states do not matter in this test.
	state ClusterControllerData data(ClusterControllerFullInterface(),
	                                 LocalityData(),
	                                 ServerCoordinators(Reference<IClusterConnectionRecord>(
	                                     new ClusterConnectionMemoryRecord(ClusterConnectionString()))));
	state NetworkAddress workerAddress(IPAddress(0x01010101), 1);
	state NetworkAddress badPeer1(IPAddress(0x02020202), 1);
	state NetworkAddress badPeer2(IPAddress(0x03030303), 1);
	state NetworkAddress badPeer3(IPAddress(0x04040404), 1);

	// Create a `UpdateWorkerHealthRequest` with two bad peers, and they should appear in the `workerAddress`'s
	// degradedPeers.
	{
		UpdateWorkerHealthRequest req;
		req.address = workerAddress;
		req.degradedPeers.push_back(badPeer1);
		req.degradedPeers.push_back(badPeer2);
		data.updateWorkerHealth(req);
		ASSERT(data.workerHealth.find(workerAddress) != data.workerHealth.end());
		auto& health = data.workerHealth[workerAddress];
		ASSERT_EQ(health.degradedPeers.size(), 2);
		ASSERT(health.degradedPeers.find(badPeer1) != health.degradedPeers.end());
		ASSERT_EQ(health.degradedPeers[badPeer1].startTime, health.degradedPeers[badPeer1].lastRefreshTime);
		ASSERT(health.degradedPeers.find(badPeer2) != health.degradedPeers.end());
	}

	// Create a `UpdateWorkerHealthRequest` with two bad peers, one from the previous test and a new one.
	// The one from the previous test should have lastRefreshTime updated.
	// The other one from the previous test not included in this test should be removed.
	{
		// Make the time to move so that now() guarantees to return a larger value than before.
		wait(delay(0.001));
		UpdateWorkerHealthRequest req;
		req.address = workerAddress;
		req.degradedPeers.push_back(badPeer1);
		req.degradedPeers.push_back(badPeer3);
		data.updateWorkerHealth(req);
		ASSERT(data.workerHealth.find(workerAddress) != data.workerHealth.end());
		auto& health = data.workerHealth[workerAddress];
		ASSERT_EQ(health.degradedPeers.size(), 2);
		ASSERT(health.degradedPeers.find(badPeer1) != health.degradedPeers.end());
		ASSERT_LT(health.degradedPeers[badPeer1].startTime, health.degradedPeers[badPeer1].lastRefreshTime);
		ASSERT(health.degradedPeers.find(badPeer2) == health.degradedPeers.end());
		ASSERT(health.degradedPeers.find(badPeer3) != health.degradedPeers.end());
	}

	// Create a `UpdateWorkerHealthRequest` with empty `degradedPeers`, which should remove the worker from
	// `workerHealth`.
	{
		UpdateWorkerHealthRequest req;
		req.address = workerAddress;
		data.updateWorkerHealth(req);
		ASSERT(data.workerHealth.find(workerAddress) == data.workerHealth.end());
	}

	return Void();
}

TEST_CASE("/fdbserver/clustercontroller/updateRecoveredWorkers") {
	// Create a testing ClusterControllerData. Most of the internal states do not matter in this test.
	ClusterControllerData data(ClusterControllerFullInterface(),
	                           LocalityData(),
	                           ServerCoordinators(Reference<IClusterConnectionRecord>(
	                               new ClusterConnectionMemoryRecord(ClusterConnectionString()))));
	NetworkAddress worker1(IPAddress(0x01010101), 1);
	NetworkAddress worker2(IPAddress(0x11111111), 1);
	NetworkAddress badPeer1(IPAddress(0x02020202), 1);
	NetworkAddress badPeer2(IPAddress(0x03030303), 1);

	// Create following test scenario:
	// 	 worker1 -> badPeer1 active
	// 	 worker1 -> badPeer2 recovered
	// 	 worker2 -> badPeer2 recovered
	data.workerHealth[worker1].degradedPeers[badPeer1] = {
		now() - SERVER_KNOBS->CC_DEGRADED_LINK_EXPIRATION_INTERVAL - 1, now()
	};
	data.workerHealth[worker1].degradedPeers[badPeer2] = {
		now() - SERVER_KNOBS->CC_DEGRADED_LINK_EXPIRATION_INTERVAL - 1,
		now() - SERVER_KNOBS->CC_DEGRADED_LINK_EXPIRATION_INTERVAL - 1
	};
	data.workerHealth[worker2].degradedPeers[badPeer2] = {
		now() - SERVER_KNOBS->CC_DEGRADED_LINK_EXPIRATION_INTERVAL - 1,
		now() - SERVER_KNOBS->CC_DEGRADED_LINK_EXPIRATION_INTERVAL - 1
	};
	data.updateRecoveredWorkers();

	ASSERT_EQ(data.workerHealth.size(), 1);
	ASSERT(data.workerHealth.find(worker1) != data.workerHealth.end());
	ASSERT(data.workerHealth[worker1].degradedPeers.find(badPeer1) != data.workerHealth[worker1].degradedPeers.end());
	ASSERT(data.workerHealth[worker1].degradedPeers.find(badPeer2) == data.workerHealth[worker1].degradedPeers.end());
	ASSERT(data.workerHealth.find(worker2) == data.workerHealth.end());

	return Void();
}

TEST_CASE("/fdbserver/clustercontroller/getServersWithDegradedLink") {
	// Create a testing ClusterControllerData. Most of the internal states do not matter in this test.
	ClusterControllerData data(ClusterControllerFullInterface(),
	                           LocalityData(),
	                           ServerCoordinators(Reference<IClusterConnectionRecord>(
	                               new ClusterConnectionMemoryRecord(ClusterConnectionString()))));
	NetworkAddress worker(IPAddress(0x01010101), 1);
	NetworkAddress badPeer1(IPAddress(0x02020202), 1);
	NetworkAddress badPeer2(IPAddress(0x03030303), 1);
	NetworkAddress badPeer3(IPAddress(0x04040404), 1);
	NetworkAddress badPeer4(IPAddress(0x05050505), 1);

	// Test that a reported degraded link should stay for sometime before being considered as a degraded link by
	// cluster controller.
	{
		data.workerHealth[worker].degradedPeers[badPeer1] = { now(), now() };
		ASSERT(data.getServersWithDegradedLink().empty());
		data.workerHealth.clear();
	}

	// Test that when there is only one reported degraded link, getServersWithDegradedLink can return correct
	// degraded server.
	{
		data.workerHealth[worker].degradedPeers[badPeer1] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		auto degradedServers = data.getServersWithDegradedLink();
		ASSERT(degradedServers.size() == 1);
		ASSERT(degradedServers.find(badPeer1) != degradedServers.end());
		data.workerHealth.clear();
	}

	// Test that if both A complains B and B compalins A, only one of the server will be chosen as degraded server.
	{
		data.workerHealth[worker].degradedPeers[badPeer1] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer1].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		auto degradedServers = data.getServersWithDegradedLink();
		ASSERT(degradedServers.size() == 1);
		ASSERT(degradedServers.find(worker) != degradedServers.end() ||
		       degradedServers.find(badPeer1) != degradedServers.end());
		data.workerHealth.clear();
	}

	// Test that if B complains A and C complains A, A is selected as degraded server instead of B or C.
	{
		ASSERT(SERVER_KNOBS->CC_DEGRADED_PEER_DEGREE_TO_EXCLUDE < 4);
		data.workerHealth[worker].degradedPeers[badPeer1] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer1].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[worker].degradedPeers[badPeer2] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer2].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		auto degradedServers = data.getServersWithDegradedLink();
		ASSERT(degradedServers.size() == 1);
		ASSERT(degradedServers.find(worker) != degradedServers.end());
		data.workerHealth.clear();
	}

	// Test that if the number of complainers exceeds the threshold, no degraded server is returned.
	{
		ASSERT(SERVER_KNOBS->CC_DEGRADED_PEER_DEGREE_TO_EXCLUDE < 4);
		data.workerHealth[badPeer1].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer2].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer3].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer4].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		ASSERT(data.getServersWithDegradedLink().empty());
		data.workerHealth.clear();
	}

	// Test that if the degradation is reported both ways between A and other 4 servers, no degraded server is
	// returned.
	{
		ASSERT(SERVER_KNOBS->CC_DEGRADED_PEER_DEGREE_TO_EXCLUDE < 4);
		data.workerHealth[worker].degradedPeers[badPeer1] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer1].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[worker].degradedPeers[badPeer2] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer2].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[worker].degradedPeers[badPeer3] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer3].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[worker].degradedPeers[badPeer4] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		data.workerHealth[badPeer4].degradedPeers[worker] = { now() - SERVER_KNOBS->CC_MIN_DEGRADATION_INTERVAL - 1,
			                                                  now() };
		ASSERT(data.getServersWithDegradedLink().empty());
		data.workerHealth.clear();
	}

	return Void();
}

TEST_CASE("/fdbserver/clustercontroller/recentRecoveryCountDueToHealth") {
	// Create a testing ClusterControllerData. Most of the internal states do not matter in this test.
	ClusterControllerData data(ClusterControllerFullInterface(),
	                           LocalityData(),
	                           ServerCoordinators(Reference<IClusterConnectionRecord>(
	                               new ClusterConnectionMemoryRecord(ClusterConnectionString()))));

	ASSERT_EQ(data.recentRecoveryCountDueToHealth(), 0);

	data.recentHealthTriggeredRecoveryTime.push(now() - SERVER_KNOBS->CC_TRACKING_HEALTH_RECOVERY_INTERVAL - 1);
	ASSERT_EQ(data.recentRecoveryCountDueToHealth(), 0);

	data.recentHealthTriggeredRecoveryTime.push(now() - SERVER_KNOBS->CC_TRACKING_HEALTH_RECOVERY_INTERVAL + 1);
	ASSERT_EQ(data.recentRecoveryCountDueToHealth(), 1);

	data.recentHealthTriggeredRecoveryTime.push(now());
	ASSERT_EQ(data.recentRecoveryCountDueToHealth(), 2);

	return Void();
}

TEST_CASE("/fdbserver/clustercontroller/shouldTriggerRecoveryDueToDegradedServers") {
	// Create a testing ClusterControllerData. Most of the internal states do not matter in this test.
	ClusterControllerData data(ClusterControllerFullInterface(),
	                           LocalityData(),
	                           ServerCoordinators(Reference<IClusterConnectionRecord>(
	                               new ClusterConnectionMemoryRecord(ClusterConnectionString()))));
	NetworkAddress master(IPAddress(0x01010101), 1);
	NetworkAddress tlog(IPAddress(0x02020202), 1);
	NetworkAddress satelliteTlog(IPAddress(0x03030303), 1);
	NetworkAddress remoteTlog(IPAddress(0x04040404), 1);
	NetworkAddress logRouter(IPAddress(0x05050505), 1);
	NetworkAddress backup(IPAddress(0x06060606), 1);
	NetworkAddress proxy(IPAddress(0x07070707), 1);
	NetworkAddress resolver(IPAddress(0x08080808), 1);
	NetworkAddress clusterController(IPAddress(0x09090909), 1);
	UID testUID(1, 2);

	// Create a ServerDBInfo using above addresses.
	ServerDBInfo testDbInfo;
	testDbInfo.clusterInterface.changeCoordinators =
	    RequestStream<struct ChangeCoordinatorsRequest>(Endpoint({ clusterController }, UID(1, 2)));

	MasterInterface mInterface;
	mInterface.getCommitVersion = RequestStream<struct GetCommitVersionRequest>(Endpoint({ master }, UID(1, 2)));
	testDbInfo.master = mInterface;

	TLogInterface localTLogInterf;
	localTLogInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ tlog }, testUID));
	TLogInterface localLogRouterInterf;
	localLogRouterInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ logRouter }, testUID));
	BackupInterface backupInterf;
	backupInterf.waitFailure = RequestStream<ReplyPromise<Void>>(Endpoint({ backup }, testUID));
	TLogSet localTLogSet;
	localTLogSet.isLocal = true;
	localTLogSet.tLogs.push_back(OptionalInterface(localTLogInterf));
	localTLogSet.logRouters.push_back(OptionalInterface(localLogRouterInterf));
	localTLogSet.backupWorkers.push_back(OptionalInterface(backupInterf));
	testDbInfo.logSystemConfig.tLogs.push_back(localTLogSet);

	TLogInterface sateTLogInterf;
	sateTLogInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ satelliteTlog }, testUID));
	TLogSet sateTLogSet;
	sateTLogSet.isLocal = true;
	sateTLogSet.locality = tagLocalitySatellite;
	sateTLogSet.tLogs.push_back(OptionalInterface(sateTLogInterf));
	testDbInfo.logSystemConfig.tLogs.push_back(sateTLogSet);

	TLogInterface remoteTLogInterf;
	remoteTLogInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ remoteTlog }, testUID));
	TLogSet remoteTLogSet;
	remoteTLogSet.isLocal = false;
	remoteTLogSet.tLogs.push_back(OptionalInterface(remoteTLogInterf));
	testDbInfo.logSystemConfig.tLogs.push_back(remoteTLogSet);

	GrvProxyInterface proxyInterf;
	proxyInterf.getConsistentReadVersion = RequestStream<struct GetReadVersionRequest>(Endpoint({ proxy }, testUID));
	testDbInfo.client.grvProxies.push_back(proxyInterf);

	ResolverInterface resolverInterf;
	resolverInterf.resolve = RequestStream<struct ResolveTransactionBatchRequest>(Endpoint({ resolver }, testUID));
	testDbInfo.resolvers.push_back(resolverInterf);

	testDbInfo.recoveryState = RecoveryState::ACCEPTING_COMMITS;

	// No recovery when no degraded servers.
	data.db.serverInfo->set(testDbInfo);
	ASSERT(!data.shouldTriggerRecoveryDueToDegradedServers());

	// Trigger recovery when master is degraded.
	data.degradedServers.insert(master);
	ASSERT(data.shouldTriggerRecoveryDueToDegradedServers());
	data.degradedServers.clear();

	// Trigger recovery when primary TLog is degraded.
	data.degradedServers.insert(tlog);
	ASSERT(data.shouldTriggerRecoveryDueToDegradedServers());
	data.degradedServers.clear();

	// No recovery when satellite Tlog is degraded.
	data.degradedServers.insert(satelliteTlog);
	ASSERT(!data.shouldTriggerRecoveryDueToDegradedServers());
	data.degradedServers.clear();

	// No recovery when remote tlog is degraded.
	data.degradedServers.insert(remoteTlog);
	ASSERT(!data.shouldTriggerRecoveryDueToDegradedServers());
	data.degradedServers.clear();

	// No recovery when log router is degraded.
	data.degradedServers.insert(logRouter);
	ASSERT(!data.shouldTriggerRecoveryDueToDegradedServers());
	data.degradedServers.clear();

	// No recovery when backup worker is degraded.
	data.degradedServers.insert(backup);
	ASSERT(!data.shouldTriggerRecoveryDueToDegradedServers());
	data.degradedServers.clear();

	// Trigger recovery when proxy is degraded.
	data.degradedServers.insert(proxy);
	ASSERT(data.shouldTriggerRecoveryDueToDegradedServers());
	data.degradedServers.clear();

	// Trigger recovery when resolver is degraded.
	data.degradedServers.insert(resolver);
	ASSERT(data.shouldTriggerRecoveryDueToDegradedServers());

	return Void();
}

TEST_CASE("/fdbserver/clustercontroller/shouldTriggerFailoverDueToDegradedServers") {
	// Create a testing ClusterControllerData. Most of the internal states do not matter in this test.
	ClusterControllerData data(ClusterControllerFullInterface(),
	                           LocalityData(),
	                           ServerCoordinators(Reference<IClusterConnectionRecord>(
	                               new ClusterConnectionMemoryRecord(ClusterConnectionString()))));
	NetworkAddress master(IPAddress(0x01010101), 1);
	NetworkAddress tlog(IPAddress(0x02020202), 1);
	NetworkAddress satelliteTlog(IPAddress(0x03030303), 1);
	NetworkAddress remoteTlog(IPAddress(0x04040404), 1);
	NetworkAddress logRouter(IPAddress(0x05050505), 1);
	NetworkAddress backup(IPAddress(0x06060606), 1);
	NetworkAddress proxy(IPAddress(0x07070707), 1);
	NetworkAddress proxy2(IPAddress(0x08080808), 1);
	NetworkAddress resolver(IPAddress(0x09090909), 1);
	NetworkAddress clusterController(IPAddress(0x10101010), 1);
	UID testUID(1, 2);

	data.db.config.usableRegions = 2;

	// Create a ServerDBInfo using above addresses.
	ServerDBInfo testDbInfo;
	testDbInfo.clusterInterface.changeCoordinators =
	    RequestStream<struct ChangeCoordinatorsRequest>(Endpoint({ clusterController }, UID(1, 2)));

	TLogInterface localTLogInterf;
	localTLogInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ tlog }, testUID));
	TLogInterface localLogRouterInterf;
	localLogRouterInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ logRouter }, testUID));
	BackupInterface backupInterf;
	backupInterf.waitFailure = RequestStream<ReplyPromise<Void>>(Endpoint({ backup }, testUID));
	TLogSet localTLogSet;
	localTLogSet.isLocal = true;
	localTLogSet.tLogs.push_back(OptionalInterface(localTLogInterf));
	localTLogSet.logRouters.push_back(OptionalInterface(localLogRouterInterf));
	localTLogSet.backupWorkers.push_back(OptionalInterface(backupInterf));
	testDbInfo.logSystemConfig.tLogs.push_back(localTLogSet);

	TLogInterface sateTLogInterf;
	sateTLogInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ satelliteTlog }, testUID));
	TLogSet sateTLogSet;
	sateTLogSet.isLocal = true;
	sateTLogSet.locality = tagLocalitySatellite;
	sateTLogSet.tLogs.push_back(OptionalInterface(sateTLogInterf));
	testDbInfo.logSystemConfig.tLogs.push_back(sateTLogSet);

	TLogInterface remoteTLogInterf;
	remoteTLogInterf.peekMessages = RequestStream<struct TLogPeekRequest>(Endpoint({ remoteTlog }, testUID));
	TLogSet remoteTLogSet;
	remoteTLogSet.isLocal = false;
	remoteTLogSet.tLogs.push_back(OptionalInterface(remoteTLogInterf));
	testDbInfo.logSystemConfig.tLogs.push_back(remoteTLogSet);

	GrvProxyInterface grvProxyInterf;
	grvProxyInterf.getConsistentReadVersion = RequestStream<struct GetReadVersionRequest>(Endpoint({ proxy }, testUID));
	testDbInfo.client.grvProxies.push_back(grvProxyInterf);

	CommitProxyInterface commitProxyInterf;
	commitProxyInterf.commit = RequestStream<struct CommitTransactionRequest>(Endpoint({ proxy2 }, testUID));
	testDbInfo.client.commitProxies.push_back(commitProxyInterf);

	ResolverInterface resolverInterf;
	resolverInterf.resolve = RequestStream<struct ResolveTransactionBatchRequest>(Endpoint({ resolver }, testUID));
	testDbInfo.resolvers.push_back(resolverInterf);

	testDbInfo.recoveryState = RecoveryState::ACCEPTING_COMMITS;

	// No failover when no degraded servers.
	data.db.serverInfo->set(testDbInfo);
	ASSERT(!data.shouldTriggerFailoverDueToDegradedServers());

	// No failover when small number of degraded servers
	data.degradedServers.insert(master);
	ASSERT(!data.shouldTriggerFailoverDueToDegradedServers());
	data.degradedServers.clear();

	// Trigger failover when enough servers in the txn system are degraded.
	data.degradedServers.insert(master);
	data.degradedServers.insert(tlog);
	data.degradedServers.insert(proxy);
	data.degradedServers.insert(proxy2);
	data.degradedServers.insert(resolver);
	ASSERT(data.shouldTriggerFailoverDueToDegradedServers());

	// No failover when usable region is 1.
	data.db.config.usableRegions = 1;
	ASSERT(!data.shouldTriggerFailoverDueToDegradedServers());
	data.db.config.usableRegions = 2;

	// No failover when remote is also degraded.
	data.degradedServers.insert(remoteTlog);
	ASSERT(!data.shouldTriggerFailoverDueToDegradedServers());
	data.degradedServers.clear();

	// No failover when some are not from transaction system
	data.degradedServers.insert(NetworkAddress(IPAddress(0x13131313), 1));
	data.degradedServers.insert(NetworkAddress(IPAddress(0x13131313), 2));
	data.degradedServers.insert(NetworkAddress(IPAddress(0x13131313), 3));
	data.degradedServers.insert(NetworkAddress(IPAddress(0x13131313), 4));
	data.degradedServers.insert(NetworkAddress(IPAddress(0x13131313), 5));
	ASSERT(!data.shouldTriggerFailoverDueToDegradedServers());
	data.degradedServers.clear();

	return Void();
}

} // namespace