itzg / Docker Bungeecord

This is a Docker image of BungeeCord and is intended to be used at the front-end of a cluster of itzg/minecraft-server containers.

Using with itzg/minecraft-server image

When using with the server image itzg/minecraft-server you can disable online mode, which is required by bungeecord, by setting ONLINE_MODE=FALSE, such as

docker run ... -e ONLINE_MODE=FALSE itzg/minecraft-server

Here is an example Docker Compose file.

Healthcheck

This image contains mc-monitor and uses its status command to continually check on the container's. That can be observed from the STATUS column of docker ps

CONTAINER ID    IMAGE    COMMAND                         CREATED           STATUS                     PORTS                       NAMES
b418af073764    mc       "/usr/bin/run-bungeecord.sh"    43 seconds ago    Up 41 seconds (healthy)    0.0.0.0:25577->25577/tcp    mc

You can also query the container's health in a script friendly way:

> docker container inspect -f "{{.State.Health.Status}}" mc
healthy

Environment Settings

• TYPE=BUNGEECORD

  The type of the server. When the type is set to CUSTOM, the environment setting BUNGEE_JAR_URL is required.

  Possible values:

  • BUNGEECORD
  • WATERFALL
  • VELOCITY
  • CUSTOM

• MEMORY=512m

  The Java memory heap size to specify to the JVM.

• INIT_MEMORY=${MEMORY}

  Can be set to use a different initial heap size.

• MAX_MEMORY=${MEMORY}

  Can be set to use a different max heap size.

• JVM_OPTS

  Additional -X options to pass to the JVM.

• PLUGINS

  Used to download a comma seperated list of *.jar urls to the plugins folder.

  -e PLUGINS=https://www.example.com/plugin1.jar,https://www.example.com/plugin2.jar
  

• ENABLE_RCON

  Enable the rcon server (that uses a third-party plugin to work, orblazer/bungee-rcon, which is automatically downloaded)

• RCON_PORT

  Define the port for rcon

• RCON_PASSWORD

  Define the password for rcon

Optional Environment Settings

• BUNGEE_JOB_ID=lastStableBuild

  The Jenkins job ID of the artifact to download and run and is used when deriving the default value of BUNGEE_JAR_URL

• BUNGEE_JAR_REVISION

  Defaults to the value of ${BUNGEE_JOB_ID}, but can be set to an arbitrarily incremented value to force an upgrade of the downloaded BungeeCord jar file.

• BUNGEE_BASE_URL

  Default to:

  • (type BUNGEECORD): https://ci.md-5.net/job/BungeeCord
  • (type WATERFALL): https://papermc.io/ci/job/Waterfall/

  Used to derive the default value of BUNGEE_JAR_URL

• BUNGEE_JAR_URL

  If set, can specify a custom, fully qualified URL of the BungeeCord.jar; however, you won't be able reference the other environment variables from within a docker run a compose file. Defaults to:

  • (type: BUNGEECORD): ${BUNGEE_BASE_URL}/${BUNGEE_JOB_ID}/artifact/bootstrap/target/BungeeCord.jar

  This takes precedence over BUNGEE_JAR_FILE.

• BUNGEE_JAR_FILE

  For TYPE=CUSTOM, allows setting a custom BungeeCord JAR that is located inside the container.

  Must be a valid path of an existing file.

• WATERFALL_VERSION=latest

  For TYPE=WATERFALL, allows downloading a specific release stream of Waterfall.

• WATERFALL_BUILD_ID=latest

  For TYPE=WATERFALL, allows downloading a specific build of Waterfall within the given version.

• VELOCITY_VERSION=latest

  For TYPE=VELOCITY, specifies the version of Velocity to download and run.

Volumes

• /server

  The working directory where BungeeCord is started. This is the directory where its config.yml will be loaded.

• /plugins

  Plugins will be copied across from this directory before the server is started.

• /config

  The /config/config.yml file in this volume will be copied accross on startup if it is newer than the config in /server/config.yml.

  If server-icon.png, modules.yml, waterfall.yml or messages.properties also exists in the volume, they will also be copied if newer.

Ports

• 25577

  The listening port of BungeeCord, which you will typically want to port map to the standard Minecraft server port of 25565 using:

  -p 25565:25577
  

Interacting with the server

RCON is enabled by default, so you can exec into the container to access the Bungeecord server console:

docker exec -i mc rcon-cli

Note: The -i is required for interactive use of rcon-cli.

To run a simple, one-shot command, such as stopping a Bungeecord server, pass the command as arguments to rcon-cli, such as:

docker exec mc rcon-cli en

The -i is not needed in this case.

In order to attach and interact with the Bungeecord server, add -it when starting the container, such as

docker run -d -it -p 25565:25577 --name mc itzg/docker-bungeecord

With that you can attach and interact at any time using

docker attach mc

and then Control-p Control-q to detach.

For remote access, configure your Docker daemon to use a tcp socket (such as -H tcp://0.0.0.0:2375) and attach from another machine:

docker -H $HOST:2375 attach mc

Unless you're on a home/private LAN, you should enable TLS access.

BungeeCord Configuration

BungeeCord Configuration Guide

Replacing variables inside configs

Sometimes you have mods or plugins that require configuration information that is only available at runtime. For example if you need to configure a plugin to connect to a database, you don't want to include this information in your Git repository or Docker image. Or maybe you have some runtime information like the server name that needs to be set in your config files after the container starts.

For those cases there is the option to replace defined variables inside your configs with environment variables defined at container runtime.

If you set the enviroment variable REPLACE_ENV_VARIABLES to TRUE the startup script will go thru all files inside your /server volume and replace variables that match your defined environment variables. Variables that you want to replace need to be wrapped inside ${YOUR_VARIABLE} curly brackets and prefixed with a dollar sign. This is the regular syntax for enviromment variables inside strings or config files.

Optionally you can also define a prefix to only match predefined enviroment variables.

ENV_VARIABLE_PREFIX="CFG_" <-- this is the default prefix

If you want use file for value (like when use secrets) you can add suffix _FILE to your variable name (in run command).

There are some limitations to what characters you can use.

Variables will be replaced in files with the following extensions: .yml, .yaml, .toml, .txt, .cfg, .conf, .properties.

Here is a full example where we want to replace values inside a database.yml.

---
database:
  host: ${CFG_DB_HOST}
  name: ${CFG_DB_NAME}
  password: ${CFG_DB_PASSWORD}

This is how your docker-compose.yml file could look like:

version: "3"
# Other docker-compose examples in /examples

services:
  proxy:
    image: itzg/bungeecord
    ports:
      - "25577:25577"
    volumes:
      - "proxy:/server"
    environment:
      # enable env variable replacement
      REPLACE_ENV_VARIABLES: "TRUE"
      # define an optional prefix for your env variables you want to replace
      ENV_VARIABLE_PREFIX: "CFG_"
      # and here are the actual variables
      CFG_DB_HOST: "http://localhost:3306"
      CFG_DB_NAME: "minecraft"
      CFG_DB_PASSWORD_FILE: "/run/secrets/db_password"
    restart: always

volumes:
  proxy:

secrets:
  db_password:
    file: ./db_password

The content of db_password:

ug23u3bg39o-ogADSs

Scenarios

Running non-root

This image may be run as a non-root user but does require an attached /server volume that is writable by that uid, such as:

docker run ... -u $uid -v $(pwd)/data:/server itzg/bungeecord