support init container/runtime container split for k8s deployment

[RonnyPfannschmidt]

Enhancement Type

Improve an existing feature

Describe the enhancement

k8s support modes of operation for a "pod" where one container acts as init container and does prep work to then have the actual containers take over running of the service

i believe it would be really nice to have that option by enabling to run either just the mod downloader/updater or to run only the server itself

this might also be a nice starting point for a mode of operation where one wants to build a image that contains the mods/datapacks to use so that downloading/plugin updating could be part of a CD pipeline while the deployment only ever would run the server

[itzg]

It's an interesting idea, but I will need to think more about the general feasibility since the final Java process invocation is derived from the setup prior to it. I'm thinking server type, selected version, entry jar file name, and even more so the dynamic nature of a modpack declaring those aspects.

In the meantime, you can always the split steps somewhat by using setup only mode for init

https://docker-minecraft-server.readthedocs.io/en/latest/configuration/misc-options/#setup-only

and then use the generated command line invocation for the server itself.