The systemd monitoring daemon is a tool to monitor systemd unit states via dbus. This Docker image encapsulates the functionality into a container which can communicate to dbus via volume mounts.
Using This Image
There are two items that need to be taken into consideration when running this image: 1) communication with dbus, and 2) writing a config file. After creating a directory with a
config.yml, a typical way to invoke the monitoring daemon would be like this:
docker run --name systemd_mon -v /var/run/dbus/system_bus_socket:/var/run/dbus/system_bus_socket -v /path/to/config/dir:/etc/systemd_mon -d tylerjl/systemd_mon
This will start the daemon and watch for unit state on the volume mounted dbus socket.
See the docs for systemd_mon to find how to properly configure the daemon.
Note: It is possible to configure systemd_mon dynamically with environment variables and parsing/writing the config at runtime, but it feels pretty hacky in practice, so it's probably a good idea to avoid it.