There's obviously a bug or something in `mqttmarionette` because it
occasionally gets "stuck" in a state where it is running but does
not reconnect to the MQTT broker. In such situations, it has to be
restarted (and even then it doesn't shut down correctly but has to
be killed with SIGKILL, usually). I have been doing this manually, but
with this shell script and a corresponding "shell command" integration
in Home Assistant, it can be done automatically. This is similar to
how Home Assistant restarts Mopidy on the living room stereo when it
gets into the same kind of state.
Dustin