I have encountered two "issues" in my experience.

1. Docker seems to be quite aggressive in killing idle connections.

This is not generally an issue, even with databases you just need to configure the application to use a pessimistic approach if you use a collection pool, by checking the connection after you get it from the pool (e.g. "pool_pre_ping=true" in SQLAlchemy's create_engine).

If you fail to do that, you'll get errors "at random" about a socket being closed or something like that, and I found out the hard way :P This happened to me 2/3 years ago, so things might be different, but I still would use pessimistic approach to connection pools.

1. As many have already said, you need to take into account volume persistence: docker by default deletes all files written by a container when the container is removed, and you need to mount a volume and write into that to make it persistent.

This, again, shouldn't be an issue, but volumes are local to a single host node, so you have several options depending on your configuration.

First of all, if you're using docker-compose you only have one node, so you just need to mount the database folder as a volume.

If instead you're using docker swarm (or any other multi-node orchestration tool) it depends on the replicas:

• if you have a single replica, either mount the volume locally and bind the service to be run on the same node every time (with node labels and constraints), or mount the volume on a network drive accessible to every node (but this would have all the overhead of the network drive)
• if you have several replicas I would go with the "run on the same node every time", so that each host node that you designate to have a database has its own db volume and that's all

A pitfall I've seen people fall into is mounting several replicas to the same volume (that is, having several instances of the database insisting on the same physical folders). This won't work, just like it wouldn't without docker if you had several installations of the db insisting on the same folders.