Minecraft Docker Image

Motivation

There are many Minecraft Docker images already developed, why develop another?

From what I was able to find, no Minecraft Docker image currently handles signals. That means when a docker stop command is issued, Docker will attempt to signal the process to gracefully quits, but the process ignores it. Docker then terminates the server without the Minecraft server saving the state, leaving the potential of corrupted data.

By writing a simple wrapper (wrapper.py), this image is able to process the SIGTERM signal that is sent by Docker during a docker stop command. That is then turned into an RCON call, which instructs the server to safely exit and close.

In order to keep simplicity, the container will be mounted to paths on the host disk. This will allow existing automation that manages things like ops.txt or server.properties to continue to work.

Usage (Vanilla Minecraft)

# Copy configuraitons into Minecraft directory (If you have automation in
# place, run that here; that shouldn't need to change).
mkdir -p /srv/minecraft/
cp ~/my_server.properties /srv/minecraft/server.properties
echo "eula=true" > /srv/minecraft/eula.txt"

# Start Minecraft Server
docker run \
  -e MINECRAFT_VERISON=1.11.2 \
  -v /srv/minecraft/:/minecraft/:rw \
  --publish 25565:25565 \
  mide/minecraft:latest

Options & Settings

Required

Option	Expected Value	Location
enable-rcon	true	server.properties
rcon.password	Your RCON Password	server.properties
rcon.port	Your RCON Port	server.properties
eula	true	eula.txt
MINECRAFT_VERSION	Something like 1.11.2	Environment Variable

Optional

Option	Description	Default Value	Location
JAVA_TOOL_OPTIONS	JVM Settings, like heap size	-Xmx1024M -Xms1024M	Environment Variable
broadcast-rcon-to-ops	Announce RCON commands to Server Ops	false ??? TODO	server.properties

A Note On Versions

This image used to download the server .jar by a special URL but with 1.13, Minecraft changed the pattern of releasing their files. This image has been updated to use the new method, and should continue to work for older versions. More testing in this area is likely needed.