I'm using Redis with replication (slaveof directive) + Sentinel (for automatic failover). It seems that NodeBB may not support this? The problem is, that I need to be connected to the master, and it can be any one of the 3 nodes I'm running. It can change dynamically. ioredis has support for sentinel: https://github.com/luin/ioredis#sentinel Would it be possible to make this work somehow?

I see that I had to execute ./nodebb build in the container. I am guessing that it is because after removing the container, the build directory was gone and needed to be rebuilt, which tells me I have to put a build command on every container startup. This is not very optimal. I am hoping at some point in the future we can have a more hands-off docker-friendly deployment (like with env vars and all).

That is correct. The port if not defined at all is assumed to be 4567, and should only be in the url if the port is required to access the site.