Add retry logic in runliveinstaller to ensure network access during pxe boot (#3257)

* update runliveinstaller

* Update toolkit/resources/imageconfigs/additionalfiles/iso_initrd/root/runliveinstaller

Co-authored-by: Pawel Winogrodzki <pawelwi@microsoft.com>

* Update toolkit/resources/imageconfigs/additionalfiles/iso_initrd/root/runliveinstaller

Co-authored-by: Pawel Winogrodzki <pawelwi@microsoft.com>

* change to lowercase

* fix typos

Co-authored-by: Henry Li <lihl@microsoft.com>
Co-authored-by: Pawel Winogrodzki <pawelwi@microsoft.com>

toolkit/resources/imageconfigs/additionalfiles/iso_initrd/root/runliveinstaller

@@ -10,7 +10,6 @@ CONFIG_ROOT=$ISO_ROOT/config
 UNATTENDED_CONFIG_FILE=$CONFIG_ROOT/unattended_config.json
 
 # PXE boot setup
-SERVER_CONFIG_PATH=""
 CMDLINE=/proc/cmdline
 
 # parse script parameters:
@@ -38,6 +37,19 @@ done
 mkdir -p $ISO_ROOT
 LABEL=CDROM
 
+function retry {
+    local retry=0
+    local limit=10
+    local sleep_seconds=15
+    while [ $retry -lt $limit ]
+    do
+        "$@" && break
+        echo "$@" failed. Retrying... 
+        ((retry++))
+        sleep $sleep_seconds
+    done
+}
+
 if grep -qs $ISO_ROOT /proc/mounts; then
     echo ISO root already mounted
 # Read from /proc/cmdline to get image configs from PXE server
@@ -46,6 +58,12 @@ elif grep -q "image-config" $CMDLINE; then
     # $IMAGE_CONFIG_VALUE will be in this fixed format: http://PXE_SERVER_IP/RANDOM_PATH
     # CUT_DIRS will be an array of strings separated by '/'
     IFS='/' read -ra CUT_DIRS <<< $IMAGE_CONFIG_VALUE
+    
+    # It is possible that the installation environment does not have network access yet when
+    # this script is first run. So use a retry loop 
+    PXE_SERVER_IP=$(echo "$IMAGE_CONFIG_VALUE" | sed -e 's|^[^/]*//||' -e 's|/.*$||')
+    retry ping -c 1 $PXE_SERVER_IP
+
     # To disable generation of any extra directories and just download the contents within the directory, 
     # use -nH to disable genration of host-prefix, "PXE_SERVER_IP". 
     # To disable generation of "RANDOM_PATH", set --cut-dirs to the number of strings separated by '/'. 
@@ -58,16 +76,7 @@ else
     echo Attempt to mount the ISO root
     # It is possible that the partition isn't ready to be mounted when this script
     # is first run. So use a retry loop.
-    RETRY=0
-    LIMIT=5
-    SLEEPSECONDS=2
-    while [ $RETRY -lt $LIMIT ]
-    do
-        mount -L $LABEL -o ro $ISO_ROOT && break
-        echo Mount failed. Retrying...
-        ((RETRY++))
-        sleep $SLEEPSECONDS
-    done
+    retry mount -L $LABEL -o ro $ISO_ROOT
 fi
 
 if [[ ! -f "$UNATTENDED_CONFIG_FILE" ]]; then