This container is the basic bare minimum needed to run a minecraft server in a Docker container. It also does regular backups using rdiff-backup.
To run using docker-compose:
version: "2.1"
services:
minecraft:
image: minecraft-docker:latest
container_name: minecraft
environment:
- PUID=1000 # Set to the same as the host user to keep file permissions sane
- PGID=1000
- TZ=Europe/New_York # Currently unused. TODO: Implement
- MC_VERSION=latest_release # See below for options
- RCON_PASSWORD=password # Should match `rcon.password` in server.properties
- RCON_PORT=25575 # Optional, defaults to 25575. Should match `rcon.port` in server.properties
- BACKUP_SCHEDULE='0 */2 * * * *' # Use cron syntax here. This example backs up every 2 hours.
volumes:
- /path/to/server/folder:/server
- /path/to/backup/folder:/backup
ports:
- 25565:25565 # Make sure the container port (the one after the colon) matches 'server-port' in server.properties
- 25575:25575 # Optional, to expose the server RCON outside of the container
restart: unless-stopped
This container is designed to be fairly flexible, in terms of custom or modified servers. However, there are a few specific settings which must be enabled for the scripts to work correctly:
- In
server.properties:enable-rcon=true: Enable the RCON connection, so that the scripts in this container can interact with the server (For example, to send thestopcommand when the container stops)rcon.passwordshould be the same as the container environment variableRCON_PASSWORDrcon.portshould be the same as the container environment variableRCON_PORTserver-portshould be exposed in the container'sportssettings.
Minecraft servers create a lot of files. By default, docker containers run everything as the root user, with UID 0. Because you'll probably use this container by bind-mounting your server folder from your host, this could result in a world folder that's difficult to work with because it is owned by the root user.
To fix this, just pass in the PUID and PGID environment variables to be equal to the $UID and $GID of your
host user. The container will run the Minecraft server under a user with the same UID and GID, so the resulting
files will all be owned by your user on the host.
TL;DR: If you only have 1 user account on your computer, probably just leave PUID and PGID as 1000, like in the
example above.
This container can be configured to automatically update the Minecraft server on startup. To control this,
use the MC_VERSION environment variable when you create the container:
MC_VERSION=latest_release: Download the latest release versionMC_VERSION=latest_snapshot: Download the latest snapshot/prerelease versionMC_VERSION=1.16.1: Download the exact given versionMC_VERSIONis unset: Skip automatic updates completely. You'll have to provide a server jar.
If MC_VERSION is set, then the server is downloaded immediately on container launch. Any errors
will be printed to the container's console. The server will be saved to /server/server.jar within
the container (which has, presumably, been linked to a directory on the host). If this file
already exists, and is already the correct version, then no download is done.
You can use a custom/modified server jar. There are two ways to do this:
- Disable server auto-updates by leaving
MC_VERSIONunset, and put your custom jar at/server/server.jar. - Name your custom server something other than
server.jar, and create a customrunserver.sh(see below).- You should also disable server auto-updates, but if you don't, the only downside is that the server is unnecessarily downloaded and not used.
The entrypoint of this container expects the file /server/runserver.sh to be used the launch the server.
The auto-update script will check whether this file exists. If not, it will copy over the default one located
in the scripts folder.
Your runserver.sh can do whatever you want: Set java parameters (like memory), run an extra backup
on server startup/shutdown, or whatever else. But all it really needs to do is launch your server.
The entrypoint.sh will launch your runserver.sh script as the minecraft user, not as root.
This container automatically backs up the entire contents of /server to /backup. To control
how often this backup happens, use the BACKUP_SCHEDULE environment variable, following
cron syntax.
The backups are created using rdiff-backup. Because these are differential backups, they take up much less space than doing a full mirror every time.