Could not connect to asm due to following error ora-01031: insufficient privilege on RAC DB creation

Version: 

11.2.0.3.0 in RHEL 6

Scenario: 

A RAC DB creation on two nodes using DBCA.
Chose ASM as storage type in the Storage Type details screen of DBCA. But the disk groups those were created already were not visible.

Tried giving +DATA manually and clicked Next, and ended up getting the following error.


"Could not connect to asm due to following error ora-01031: insufficient privilege"

Verified from ASMCMD > lsdg command that all the disk groups were mounted.

Reason:

This was clearly a case of missing privilege as indicated by the error

Grid software owner was "grid" and DB S/W owner was "oracle". I missed to add "asmdba" as a secondary group to oracle user. 

[root@node1 app]# id oracle
uid=1901(oracle) gid=54321(oinstall) groups=8500(dba),8501(oper),54321(oinstall)


Solution:

Added asmdba as a secondary group to oracle. 

/usr/sbin/usermod -g oinstall -G dba,oper,asmdba oracle

[root@node1 app]# id oracle
uid=1901(oracle) gid=54321(oinstall) groups=8500(dba),8501(oper),9601(asmdba),54321(oinstall)

Took a new terminal session as "oracle" and re initiated DBCA.

This time the disk groups were displayed and chosen by default.