[fast/warm reboot] ignore errors after shutting down critical service…

…(s) (sonic-net#761)

Once any critical service is shutdown (radv/swss/syncd), we have to
commit to the reboot. Failing in the middle will leave the system in
bad state.

Signed-off-by: Ying Xie <ying.xie@microsoft.com>

scripts/fast-reboot

@@ -144,7 +144,6 @@ function request_pre_shutdown()
     debug "Requesting pre-shutdown ..."
     /usr/bin/docker exec -i syncd /usr/bin/syncd_request_shutdown --pre &> /dev/null || {
         error "Failed to request pre-shutdown"
-        exit "${EXIT_SYNCD_SHUTDOWN}"
     }
 }
 
@@ -180,9 +179,9 @@ function wait_for_pre_shutdown_complete_or_fail()
 
     if [[ x"${STATE}" != x"pre-shutdown-succeeded" ]]; then
         debug "Syncd pre-shutdown failed: ${STATE} ..."
-        exit "${EXIT_SYNCD_SHUTDOWN}"
+    else
+        debug "Pre-shutdown succeeded ..."
     fi
-    debug "Pre-shutdown succeeded ..."
 }
 
 function backup_database()
@@ -402,6 +401,10 @@ if [[ "$REBOOT_TYPE" = "warm-reboot" || "$REBOOT_TYPE" = "fastfast-reboot" ]]; t
     fi
 fi
 
+# We are fully committed to reboot from this point on becasue critical
+# service will go down and we cannot recover from it.
+set +e
+
 # Kill radv before stopping BGP service to prevent annoucing our departure.
 debug "Stopping radv ..."
 docker kill radv &>/dev/null || [ $? == 1 ]
@@ -474,7 +477,7 @@ if [[ "$REBOOT_TYPE" = "warm-reboot" || "$REBOOT_TYPE" = "fastfast-reboot" ]]; t
 fi
 
 debug "Stopping syncd ..."
-systemctl stop syncd
+systemctl stop syncd || debug "Ignore stopping syncd service error $?"
 debug "Stopped  syncd ..."
 
 # Kill other containers to make the reboot faster
@@ -485,20 +488,20 @@ debug "Stopping all remaining containers ..."
 for CONTAINER_NAME in $(docker ps --format '{{.Names}}'); do
     CONTAINER_STOP_RC=0
     docker kill $CONTAINER_NAME &> /dev/null || CONTAINER_STOP_RC=$?
-    systemctl stop $CONTAINER_NAME
+    systemctl stop $CONTAINER_NAME || debug "Ignore stopping $CONTAINER_NAME error $?"
     if [[ CONTAINER_STOP_RC -ne 0 ]]; then
         debug "Failed killing container $CONTAINER_NAME RC $CONTAINER_STOP_RC ."
     fi
 done
 debug "Stopped all remaining containers ..."
 
 # Stop the docker container engine. Otherwise we will have a broken docker storage
-systemctl stop docker.service
+systemctl stop docker.service || debug "Ignore stopping docker service error $?"
 
 # Stop kernel modules for Nephos platform
 if [[ "$sonic_asic_type" = 'nephos' ]];
 then
-  systemctl stop nps-modules-`uname -r`.service
+  systemctl stop nps-modules-`uname -r`.service || debug "Ignore stopping nps service error $?"
 fi
 
 # Update the reboot cause file to reflect that user issued this script