Postgres service not starting

I have the following in my .gitlab-ci.yml file:

  - postgres:9.6

But I don’t see anything about the service actually being started in my CI pipeline logs. Should I be expecting to see something about the service starting? Of course I’m not able to connect to the host “postgres” which is why I’m looking to see if the postgres service even started, but I can’t see any evidence that it did.