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linux-sg2042/Documentation/networking/net_failover.rst

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net: Introduce net_failover driver The net_failover driver provides an automated failover mechanism via APIs to create and destroy a failover master netdev and manages a primary and standby slave netdevs that get registered via the generic failover infrastructure. The failover netdev acts a master device and controls 2 slave devices. The original paravirtual interface gets registered as 'standby' slave netdev and a passthru/vf device with the same MAC gets registered as 'primary' slave netdev. Both 'standby' and 'failover' netdevs are associated with the same 'pci' device. The user accesses the network interface via 'failover' netdev. The 'failover' netdev chooses 'primary' netdev as default for transmits when it is available with link up and running. This can be used by paravirtual drivers to enable an alternate low latency datapath. It also enables hypervisor controlled live migration of a VM with direct attached VF by failing over to the paravirtual datapath when the VF is unplugged. Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:15 +08:00
.. SPDX-License-Identifier: GPL-2.0
============
NET_FAILOVER
============
Overview
========
The net_failover driver provides an automated failover mechanism via APIs
to create and destroy a failover master netdev and mananges a primary and
standby slave netdevs that get registered via the generic failover
infrastructrure.
The failover netdev acts a master device and controls 2 slave devices. The
original paravirtual interface is registered as 'standby' slave netdev and
a passthru/vf device with the same MAC gets registered as 'primary' slave
netdev. Both 'standby' and 'failover' netdevs are associated with the same
'pci' device. The user accesses the network interface via 'failover' netdev.
The 'failover' netdev chooses 'primary' netdev as default for transmits when
it is available with link up and running.
This can be used by paravirtual drivers to enable an alternate low latency
datapath. It also enables hypervisor controlled live migration of a VM with
direct attached VF by failing over to the paravirtual datapath when the VF
is unplugged.
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
virtio-net accelerated datapath: STANDBY mode
=============================================
net_failover enables hypervisor controlled accelerated datapath to virtio-net
enabled VMs in a transparent manner with no/minimal guest userspace chanages.
To support this, the hypervisor needs to enable VIRTIO_NET_F_STANDBY
feature on the virtio-net interface and assign the same MAC address to both
virtio-net and VF interfaces.
Here is an example XML snippet that shows such configuration.
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
::
<interface type='network'>
<mac address='52:54:00:00:12:53'/>
<source network='enp66s0f0_br'/>
<target dev='tap01'/>
<model type='virtio'/>
<driver name='vhost' queues='4'/>
<link state='down'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
</interface>
<interface type='hostdev' managed='yes'>
<mac address='52:54:00:00:12:53'/>
<source>
<address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/>
</source>
<address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/>
</interface>
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
Booting a VM with the above configuration will result in the following 3
netdevs created in the VM.
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
::
4: ens10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
inet 192.168.12.53/24 brd 192.168.12.255 scope global dynamic ens10
valid_lft 42482sec preferred_lft 42482sec
inet6 fe80::97d8:db2:8c10:b6d6/64 scope link
valid_lft forever preferred_lft forever
5: ens10nsby: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master ens10 state UP group default qlen 1000
link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
7: ens11: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master ens10 state UP group default qlen 1000
link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
ens10 is the 'failover' master netdev, ens10nsby and ens11 are the slave
'standby' and 'primary' netdevs respectively.
Live Migration of a VM with SR-IOV VF & virtio-net in STANDBY mode
==================================================================
net_failover also enables hypervisor controlled live migration to be supported
with VMs that have direct attached SR-IOV VF devices by automatic failover to
the paravirtual datapath when the VF is unplugged.
Here is a sample script that shows the steps to initiate live migration on
the source hypervisor.
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
::
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
# cat vf_xml
<interface type='hostdev' managed='yes'>
<mac address='52:54:00:00:12:53'/>
<source>
<address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/>
</source>
<address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/>
</interface>
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
# Source Hypervisor
#!/bin/bash
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
DOMAIN=fedora27-tap01
PF=enp66s0f0
VF_NUM=5
TAP_IF=tap01
VF_XML=
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
MAC=52:54:00:00:12:53
ZERO_MAC=00:00:00:00:00:00
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
virsh domif-setlink $DOMAIN $TAP_IF up
bridge fdb del $MAC dev $PF master
virsh detach-device $DOMAIN $VF_XML
ip link set $PF vf $VF_NUM mac $ZERO_MAC
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
virsh migrate --live $DOMAIN qemu+ssh://$REMOTE_HOST/system
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
# Destination Hypervisor
#!/bin/bash
virtio_net: Extend virtio to use VF datapath when available This patch enables virtio_net to switch over to a VF datapath when STANDBY feature is enabled and a VF netdev is present with the same MAC address. It allows live migration of a VM with a direct attached VF without the need to setup a bond/team between a VF and virtio net device in the guest. It uses the API that is exported by the net_failover driver to create and and destroy a master failover netdev. When STANDBY feature is enabled, an additional netdev(failover netdev) is created that acts as a master device and tracks the state of the 2 lower netdevs. The original virtio_net netdev is marked as 'standby' netdev and a passthru device with the same MAC is registered as 'primary' netdev. The hypervisor needs to unplug the VF device from the guest on the source host and reset the MAC filter of the VF to initiate failover of datapath to virtio before starting the migration. After the migration is completed, the destination hypervisor sets the MAC filter on the VF and plugs it back to the guest to switch over to VF datapath. This patch is based on the discussion initiated by Jesse on this thread. https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 00:55:17 +08:00
docs: networking: Fix failover build warnings Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 05:42:50 +08:00
virsh attach-device $DOMAIN $VF_XML
virsh domif-setlink $DOMAIN $TAP_IF down