self-hosting/minecraft/papermc

Build arguments

Two build arguments are required, namely MC_VERSION and PAPERMC_VERSION. You can find your required versions here. The PaperMC Version is the number starting with the #. Do note that this script only works with the currently supported Minecraft version, and not any of the legacy jars.

You can then specify the versions in the .env file:

MC_VERSION=1.16.4
PAPERMC_VERSION=352

Note that the leading # doesn't need to be added to the variable.

Environment variables

The two possible environment variables are XMS and XMX. These specify the initial RAM & maximum RAM usage respectively. Only XMX is required; XMS is just set to the same value as XMX if not specified. You must specify them as a number, e.g. XMS=4. This number represents a quantity of gigabytes.

Mount points

There a two useful mount points defined:

• /app/config: this is where all server config files reside.
• /app/worlds: this is where the world files are stored.

You can mount these directories somewhere in the host file system by specifying the mount paths in the .env file. These can be both absolute or relative paths.

Other config variables

The only other config variable is PORT. This specifies on what port your server will be discoverable over the internet. The default Minecraft port is 25565.

Java flags

I use the Java flags defined here. If you don't agree with this decision, you can change the ENTRYPOINT at the end of the Dockerfile to the following:

ENTRYPOINT java \
-Xms"${XMS}G" \
-Xmx"${XMX:-$XMS}G" \
-jar /app/server.jar \
--universe /app/worlds \
--nogui

This will only use the flags absolutely necessary, while still allowing you to tweak the memory variables.