Systemd restart and cobbler import

Every time I do _cobbler sync_, it always hangs. Tracing the issue, I found out that during _cobbler sync_, cobbler will try to restart dhcpd. However, no systemd services can be restarted. When I add this line (taken from dockerhub), it works:

> ENV container docker

Do the current code work for you when you do _cobbler sync_?
And another issue, when I do _cobbler import_, it always shows error about kickstart file not found. How do you make cobbler import the distro?

Reproduce both failures in the Docker container by running cobbler sync and cobbler import, then inspect the reported systemd restart and missing kickstart-file errors. Done means sync completes without hanging and import successfully imports a distribution; the issue does not name source files or tests to consult.

Written by the indexing model from the issue text.