FAILED_CONTACTING_OPMN Unrecognized oracle instance id OBIEE 11g

This error bumped in when we upgraded the OBIEE 11.1.1.7 to the latest patch 11.1.1.7.140225 ,the problem is simple, Presentation server is not coming up along with the scheduler.

All others are doing fine. When we checked out the logs came across this error

FAILED_CONTACTING_OPMN  Unrecognized oracle instance id: instance1 


We never got to the root cause but was able to find the workaround solution, since the error says it is not able to recognize the instance ,we thought of registering the instance once again. Luckily it worked for us.Steps to follow.

We can use the OPMN command line to register the instance. After registering, restart all the services.

$ORACLE_INSTANCE/bin/opmnctl registerinstance 

 [-adminHost hostname] 

 [-adminPort weblogic_port] 

 [-adminUsername weblogic_admin] 

 [-adminPasswordFile 'FILE_WITH_WEBLOGIC_ADMIN_PASSWORD']

for more details refer Managing Oracle Virtual Directory Server Processes - 11g Release 1 (11.1.1)