So basically.. what does it mean :-) ? What is the command line to list all images?

Since all the fuel components are installed on the Operating System(Centos 7) itself there are no docker images. You can use systemctl commands to check service details or can use fuel-utils command to check service status( fuel-utils check_service <<service_name>> )

thank you very much for the answer But the services (cobbler, nailgun, astute, postres, nginx,..) are still installed using Puppet?