After database service resources in CRS failed over to another node in a RAC Cluster, they were terminated and automatically fail back to the original node incorrectly.

CAUSE

The "fail back" was actually a relocation of the service resource, initiated by user process(UiServer):

crsd_148.trc:2017-12-19 12:24:32.701587 :UiServer:1239340800: {1:54916:896} Container [ Name: UI_RELOCATE

crsd_148.trc:2017-12-19 12:24:32.701630 :UiServer:1239340800: {1:54916:896} Sending to PE. ctx= 0x7f830003a9f0, ClientPID=96087 ===========>

crsd_148.trc:2017-12-19 12:24:32.707319 :UiServer:1239340800: {1:54916:896} Response: c4|5!ORDERk7|MESSAGEt79|CRS-2673: Attempting to stop 'ora.orcl.orclsrv.svc' on 'node1'k7|MSGTY

PEt1|3k5|OBJIDt33|ora.orcl.orclsrv.svc 1 1k4|WAITt1|0

crsd_148.trc:2017-12-19 12:24:32.777894 :UiServer:1239340800: {1:54916:896} Response: c4|5!ORDERk7|MESSAGEt78|CRS-2677: Stop of 'ora.orcl.orclsrv.svc' on 'node1' succeededk7|MSGTYP

Et1|3k5|OBJIDt33|ora.orcl.orclsrv.svc 1 1k4|WAITt1|0

crsd_148.trc:2017-12-19 12:24:32.780142 : AGFW:1251948288: {1:54916:896} Agfw Proxy Server received the message: RESOURCE_START $ora.orcl.orclsrv.svc 1 1$ ID 4098:8698047

crsd_148.trc:2017-12-19 12:24:32.780238 : AGFW:1251948288: {1:54916:896} Creating the resource: ora.orcl.orclsrv.svc 1 1

crsd_148.trc:2017-12-19 12:24:32.780339 : AGFW:1251948288: {1:54916:896} Initializing the resource ora.orcl.orclsrv.svc 1 1 for type ora.service.type

crsd_148.trc:2017-12-19 12:24:32.780380 : AGFW:1251948288: {1:54916:896} SR: acl = owner:oracle:rwx,pgrp:dba:r--,other::r--,group:dba:r-x,user:oracle:r-x

crsd_148.trc:2017-12-19 12:24:32.780665 : AGFW:1251948288: {1:54916:896} Agfw Proxy Server sending message: RESOURCE_ADD $ora.orcl.orclsrv.svc 1 1$ ID 4356:2828 to the agent /u01/app/12.1.0.2/grid/bin/oraagent_oracle

The relocate was initiated by a clientPID 96087, using a "JAVA" program:

2017-12-19 12:24:32.701587 :UiServer:1239340800: {1:54916:896} Container [ Name: UI_RELOCATE

API_HDR_VER:

TextMessage $3$

CLIENT:

TextMessage\[\]

CLIENT_NAME:
TextMessage $java$ ==============>

CLIENT_PID:
TextMessage $96087$ ================>

CLIENT_PRIMARY_GROUP:

TextMessage $dba$

Further analysis showed that this was caused due to the presence of a custom FAN (Fast Application Notification) script defined inside the $GRID_HOME/racg/usrco directory. The following example of the custom script shows that it forcibly relocates a service back to the preferred node after it has failed over to an available node:

Custom script:

if service is not running, then start it

echo " service stopped, starting" >> "$LOGFILE"

$ORACLE_HOME/bin/srvctl start service -d "$ DATABASE" -s " $service" \>\> "$ LOGFILE"

else

Service is running, but is it running on preferred instance?

RUNNING=( 'echo "$SRVSTATUS" | sed -rne "s/.* ( $a-zA-Z0-9$ +)/\1/p" | tr "," "\n"' )

echo " ${RUNNING\[@\]} =$ {PREFERRED $@$ }"

if ! in_array " $INSTANCE" "$ {RUNNING $@$ }" ; then

echo " not running on preferred $INSTANCE" \>\> "$ LOGFILE"

Find the first non-preferred running instance

CURRENT=""

for inst in "${RUNNING $@$ }"; do

if ! in_array " $inst" "$ {PREFERRED $@$ }" ; then

CURRENT="$inst"

break

done

Relocate

if $\[ -n "$CURRENT"$ ]; then

echo " relocate $CURRENT -\>$ INSTANCE" >> " $LOGFILE" **$ ORACLE_HOME/bin/srvctl relocate service -d " $DATABASE" -s "$ service" -i " $CURRENT" -t "$ INSTANCE" >> "$LOGFILE" <<<<<<<<<<<<<<<<<<<<<** <<<

else

Service is already running on preferred instance, no need to do anything

echo " running on preferred $INSTANCE" \>\> "$ LOGFILE"