What services does this image provide
This image type provides a UCS DC Slave. It's implemented as a docker layer on top of the generic "stem" image. Since it's a UCS slave, it requires that a UCS DC Master server is installed somewhere (either as VM or as docker container). This could also be a UCS DC Master server (VM or hardware) hosting the docker containers.
How to use this image
A new container running Univention Corporate Server (UCS) can be started with
docker run -d --name slave1_container --hostname=slave1 \ -e domainname=testdomain.internet \ -e nameserver1=<IP of nameserver for the container> \ -e rootpwd=<Chosen password> -p 8013:80 \ -e container=docker \ -v /sys/fs/cgroup:/sys/fs/cgroup:ro \ --tmpfs /run --tmpfs /run/lock \ --cap-add=SYS_ADMIN \ univention/ucs-slave-amd64 /sbin/init
The capabilty "SYS_ADMIN" is required, because the systemd running as init process in the container requires access to the system call "name_to_handle_at", which standard docker denies via seccomp profile by default.
Specific versions can be downloaded by specifying the version tag, e.g. univention/ucs-slave-amd64:4.2-1 . The 4.2-x versions are implemented as Docker layers.
A shell in the docker container can be started as usual by running
docker exec -it slave1_container /bin/bash
The UCS services provided by the new docker container can easily be configured through the web based appliance setup wizard. In the example above the port 8013 of the docker host is redirected to the port 80 of the container. Thus, the HTTP port of the docker container can reached by typing http://<IP of the docker host>:8013.
For more Information see the UCS manual.