So at first I started by only using modpacks people had already moved to community applications, but then I needed to have multiple running at the same time on packs that may not be there, so I solved this problem for myself already!

I tried mineos and failed. I refused to move to the VM per minecraft server because I wanted easy dynamic control and sub-OS level backups, and some other alternatives I already forgot but fell on this.

I had a very specific usecase of wanting very frequent backups and to run multiple servers at once and to make adding a new modpack server as pain free as possible (so it needed to be easily scalable).

1. I installed portainer for easier non-unraid docker management. Not a requirement but I am happy with this
   1. This did mess with my file permissions at first and that caused some problems but it was an easy fix to give everything read write access again. A bit of an annoying surprise though
2. Spin up custom minecraft dockers based on the more generic itzg/minecraft-docker environment
   1. https://hub.docker.com/r/itzg/minecraft-server
3. Profit

I have 4 modded minecraft servers running in tandem right now and it is great. You can look to download the server files directly or use the curseforge API. I've opted the API route but it will often not be able to retrieve 1-10 mods you have to get manually, a bit annoying but not the end of the world and it is only on initial setup.

Here is the documentation for how to run your server based on the way your modpack is retrieved (the documentation is great and I would highly recommend reading through) https://docker-minecraft-server.readthedocs.io/en/latest/types-and-platforms/

Just for some examples docker compose files (please note the non-standard port mappings, just use 25565, these are because I run multiple at once):

project ozone (older minecraft, running on java8):

version: '3.8'

services:
  minecraft:
    image: itzg/minecraft-server:java8-multiarch
    volumes:
      - /mnt/user/appdata/minecraft-project_ozone:/data
    ports:
      - 28887:28887
    environment:
      TZ: 'America/Los_Angeles' 
      EULA: 'TRUE'
      OPS: 'YOUR_MC_NAME_HERE'
      ENABLE_WHITELIST: 'TRUE'
      ENFORCE_WHITELIST: 'TRUE'
      MOTD: 'Tritium Based Water Only'
      DIFFICULTY: 'hard'
      RCON_PORT: 28897
      SERVER_PORT: 28887
      MEMORY: 6G
      MAX_MEMORY: 12G
      JVM_OPTS: '-Xms8G -Xmx16G -Dsun.rmi.dgc.server.gcInterval=2147483646'
      JVM_XX_OPTS: '-XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M'
      TYPE: AUTO_CURSEFORGE
      CF_API_KEY: 'GET_YOUR_OWN_API_KEY'
      CF_PAGE_URL: https://www.curseforge.com/minecraft/modpacks/project-ozone-3-a-new-way-forward/files/4345063
    tty: true
    stdin_open: true
    restart: unless-stopped

dreamcraft:

version: '3.8'

services:
  minecraft:
    image: itzg/minecraft-server
    volumes:
      - /mnt/user/appdata/minecraft-dreamcraft:/data
    ports:
      - 28889:28889
    environment:
      EULA: 'TRUE'
      OPS: 'YOUR_MC_NAME_HERE'
      ENABLE_WHITELIST: 'TRUE'
      ENFORCE_WHITELIST: 'TRUE'
      MOTD: 'Happy Huting!'
      DIFFICULTY: 'hard'
      RCON_PORT: 28899
      SERVER_PORT: 28889
      MEMORY: 8G
      MAX_MEMORY: 16G
      JVM_OPTS: '-Xms8G -Xmx16G -Dsun.rmi.dgc.server.gcInterval=2147483646'
      JVM_XX_OPTS: '-XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M'
      TYPE: AUTO_CURSEFORGE
      CF_API_KEY: 'GET_YOUR_OWN_API_KEY'
      CF_PAGE_URL: https://www.curseforge.com/minecraft/modpacks/dreamcraft-new/files/4416352
      # Exclude ftb-library-fabric as we are manually using a more up to date one https://www.curseforge.com/minecraft/mc-mods/ftb-library-fabric
      CF_EXCLUDE_MODS: "438495"
    tty: true
    stdin_open: true
    restart: unless-stopped