ConfigMaps, in our experience, are overused.

If you have a configuration that is the same across multiple clusters, or if you have only one cluster, all you should do is include it in your Dockerfile and forget it ever existed. When there are no variations of a config, there’s no need to have a configuration file. At least, not outside an immutable image.

Unfortunately, that is not always the case. To be more precise, it’s almost never the case. We tend to make things more complicated than they should be. That, among other things, often means an endless list of configuration options hardly anyone ever uses. Still, some things usually do change, from one cluster to another, and we might need to look into alternatives to configurations baked into images.