A prerequisite for the installation of Grid Infrastructure is to configure passwordless SSH connectivity.
This can be accomplished in using the following statements:
[grid@server52 ~]$ ssh-keygen -t rsa
[grid@server53 ~]$ ssh-keygen -t rsa
[grid@server52 ~]$ ssh-copy-id grid@server52
[grid@server52 ~]$ ssh-copy-id grid@server53
[grid@server53 ~]$ ssh-copy-id grid@server52
[grid@server53 ~]$ ssh-copy-id grid@server53
So far so good.
When this is performed you are ready to continue and user runcluvfy.sh to validate your environment or start the runInstaller for the Grid Infrastucture installation.
But when you have started the installation and at the screen: Cluster node Information, you can test the SSH setup performed above. But it fails, reporting
[INS-06006] Passwordless SSH connectivity not set up between the following node(s) server52,server53.
Then you try the option setup (reconfigure ssh), but again it fail, so on google you find a lot of solutions to remote /home/grid/.ssh on each node and reconfigure again, but whatever you try, restart installer ect, the problem still exists.
The issue is NOT caused by incorrect setup/configuration of SSH. But due to the environment variable SSH_AUTH_SOCK.
[grid@server52 ~]$ echo $SSH_AUTH_SOCK /run/user/1100/keyring-RLUHGM/ssh
[grid@server52 ~]$ unset SSH_AUTH_SOCK
[grid@server52 ~]$ ./runInstaller
You need to unset this environment variable and restart the runInstaller, when executed the error is gone and the Grid Infrastructure installation will continue.
Hope this helps.