Exactly, Docker is great - until you leave the beaten path. At a previous workplace I set up a VPN solution around Wireguard and Docker. We wanted to start off by integrating one physical box into our network, where containers would be spawned with a client and a customized MAC addresses to sort them into individual VLANs, which would then be accessible through the VPN.

It took a number of tries to set up correctly, especially since documentation on these areas mostly consists of reading through various issues on the Docker issue tracker. Some necessary features weren't even supported in the current Docker-Compose file versions. And best of all - 3 clients worked without a problem in parallel, any further clients were not visible in the network. No error logs or anything, just no network.

Of course this wasn't using everyday features, but it would have been nice to have a bit more of an introductory guide into the subsystem. This way it felt like I was fighting against Docker more than it was helping me.