An error message like the following in Cloud Control 12c could happen when you are going to operate the agent on the target, it indicated a permission restriction to run nmo:
Cannot run program "<path_to_agent_base>/sbin/nmo": java.io.IOException: error=2, No such file or directoryThe screenshot of this error message is as below:

Cloud Control 12c error: Cannot run program "<path_to_agent_base>/sbin/nmo": java.io.IOException: error=2, No such file or directory
The permission problem is caused by forgetting to run root.sh after agents installed. To resolve the problem, we need to execute root.sh by root on ALL nodes.
[root@primary01 ~]# export AGENT_BASE=/u01/app/oracle/product/agent
[root@primary01 ~]# $AGENT_BASE/core/12.1.0.2.0/root.sh
Finished product-specific root actions.
/etc exist
Creating /etc/oragchomelist file...
Finished product-specific root actions.
After running root.sh, said error message never shows again.
root.sh script ran successfully. But still i could see these errors Cannot run program “/sbin/nmo”: java.io.IOException: error=2, No such file or directory in gcagent.log file.
[root@ebs1dv01db1 agent_13.4.0.0.0]# . root.sh
Finished product-specific root actions.
/etc exist
Creating /etc/oragchomelist file…
[root@ebs1dv01db1 agent_13.4.0.0.0]#
Maybe a restart can be helpful.