I had a requirement to run MySQL on a VSTS hosted build agent and then to be able to run commands from outside of the container and this gave me the chance to have a play around with VSTS support for containers and builds as YAML (YAML builds / builds as YAML??).
I struggled getting started with this for a little bit longer than I would have hoped, if you have a container and want to run commands inside the container then the process is pretty straight forward, although on vsts you don't get a TTY so need to do “docker exec -i” rather than “docker exec -it” as all the examples show.