It would be really useful if there was an official Docker image for DirectAdmin, because it would allow you to spin up DA quickly and would also eliminate the chance of issues during setup (or do so closely enough).
Uhm, sorry - I don't really see how you're planning to run DA in a docker ct. I mean, sure - if you're planning to run a cluster of DA instances and you couldn't be bothered to setup VMs... but are you going to run a DA cluster? I don't really see any advantages of running it in a container vs dedi/vm. The things that you'll most likely have issues with are the config files, and those will need to be on the host server anyway, because they need to be kept between container removal/re-creation.
I can see this being useful in some auto-deployment setup in a cluster, but other than that, not really.
I'm open to discussion tho, how do you think this would improve your workflow?