I'm guessing your are referring to the Atomic images we're distributing via the oVirt (Glance) Public Image Repository. Those images vanilla copies of the images released from the relevant upstream projects, and we're not making any oVirt-specific changes to them.

I don't know much about Atomic, but as far as I know, the way to add system-level services like the ovirt-guest-agent to Atomic is to add a system container [1].

It could be an interesting project to build a container around the ovirt-guest-agent. Adding Vinzenz in case he would be interested to tackle this.

[1]: http://www.projectatomic.io/blog/2016/09/intro-to-system-containers/