The RHEL 8 docs on cockpit show how to connect up with IdM.
The RHEL 7 docs do not.
I have an IdM server and a RHEL 7 IdM client.
I installed cockpit and was able to log in using it.
When I moved the mouse cursor over "Join Domain", I got a popup that says "Cannot join a domain because realmd is not available on this system"
I am hesitant to just "yum install realmd" because I do not want to mess up the IdM client setup.