EM Configuration issue. $ORACLE_HOME/odprimary_PRIDB not found

oracle control 12c agent issue

root cause

A common cause for this error is changing the hostname of the server in either /etc/hosts or DNS. In this case the there were no changes to the hostname as we were able to connect to the hostname listed in the last known state on the database home page.

Resolution

changing /etc/hosts to the following:
127.0.0.1 localhost.localdomain localhost
172.17.100.250 cloudcc12c cloudcc12c.com

reference:

http://www.oracledistilled.com/grid-control/em-configuration-issue-oracle_homeodprimary_pridb-not-found/

http://fusionsecurity.blogspot.com/2011/05/error-message-can-not-resolve-hostname.html