That's a big reason I actively avoid docker on my servers, I don't like running a dozen instances of my database software, and considering how much work it would take to go through and configure each docker container to use an external database, to me it's just as easy to learn to configure each piece of software for yourself and know what's going on under the hood, rather than relying on a bunch of defaults made by whoever made the docker image.
I hope a good amount of my issues with docker have been solved since I last seriously tried to use docker (which was back when they were literally giving away free tee shirts to get people to try it). But the times I've peeked at it since, to me it seems that docker gets in the way more often than it solves problems.
I don't mean to yuck other people's yum though, so if you like docker, and it works for you, don't let me stop you from enjoying it. I just can't justify the overhead for myself (both at the system resource level, and personal time level of inserting an additional layer of configuration between me and my software).