GuardCraft is a containerized Minecraft (Java) server built on top of the Java JRE Chainguard Image. This is a demo that showcases the capabilities of the Chainguard Java JRE image, which is a minimal Java runtime environment with low-to-zero vulnerabilities (CVEs).
- Minimal container image with low-to-zero CVEs
- Streamlined configuration using environment variables
- Automatic updates for the server software
- Easy local network setup with Docker Compose
You can build this image from source in your local environment. Clone the repository and navigate to the guardcraft-server directory. To build the image, run:
docker build -t guardcraft-server .If you want to specify the version of the Minecraft server, you can pass the VERSION argument at build time, like this:
docker build --build-arg VERSION=1.21.4 . -t guardcraft-serverUse the following command to run the image in your local environment:
docker compose upYou should be able to see output with relevant information about the server setup:
[+] Running 1/1
✔ Container guardcraft-server-java-server-1 Recreated 0.1s
Attaching to java-server-1
java-server-1 | Setting difficulty=easy
java-server-1 | Setting gamemode=survival
java-server-1 | Setting level-name=GuardCraft
java-server-1 | Setting level-seed=-1718501946501227358
java-server-1 | Setting motd=Welcome to GuardCraft!
java-server-1 | Starting net.minecraft.server.Main
java-server-1 | [18:11:14] [ServerMain/INFO]: Environment: Environment[sessionHost=https://sessionserver.mojang.com, servicesHost=https://api.minecraftservices.com, name=PROD]
java-server-1 | [18:11:14] [ServerMain/INFO]: No existing world data, creating new world
java-server-1 | [18:11:15] [ServerMain/INFO]: Loaded 1370 recipes
java-server-1 | [18:11:15] [ServerMain/INFO]: Loaded 1481 advancements
java-server-1 | [18:11:15] [Server thread/INFO]: Starting minecraft server version 1.21.4
java-server-1 | [18:11:15] [Server thread/INFO]: Loading properties
java-server-1 | [18:11:15] [Server thread/INFO]: Default game type: SURVIVAL
java-server-1 | [18:11:15] [Server thread/INFO]: Generating keypair
java-server-1 | [18:11:15] [Server thread/INFO]: Starting Minecraft server on *:25565
...This will run an ephemeral Minecraft Java server with default settings. It will create a world in survival mode with difficulty set to "normal", and a random world seed, using the latest version of the Minecraft server. The port redirection will make the server available at localhost:25565 in the host machine.
You can connect to the server using a Minecraft Java client on the same local network.
**Please note the client must be running the same version of the server software (in this case, 1.21.5 Pre-Release 3). If you're always pulling the latest version, you'll also get beta snapshots that let you try new features of the game. In this case, you'll need to select the appropriate version in the Minecraft launcher software. For snapshot versions you must select "latest snapshot" as shown in this image:
Add a new server using the host machine's local IP address and port 25565 (the default port). You can also use the localhost address if you're running the server on the same machine as the client.
Find your local IP address on Linux systems:
ip -o route get to 8.8.8.8 | sed -n 's/.*src \([0-9.]\+\).*/\1/p'
When connecting, you should see details about your user on the server logs:
java-server-1 | [18:12:21] [Server thread/INFO]: Server empty for 60 seconds, pausing
java-server-1 | [18:14:29] [User Authenticator #1/INFO]: UUID of player boredcatmom is xxxxx-xxxx-xxxx-xxxx-xxxxxxxx
java-server-1 | [18:14:30] [Server thread/INFO]: boredcatmom[/192.168.178.167:37192] logged in with entity id 78 at (20.5, 66.0, 4.5)
java-server-1 | [18:14:30] [Server thread/INFO]: boredcatmom joined the game
The GuardCraft server can be configured using dynamic environment variables that get replaced in the server.properties file. Any properties can be configured with the following format: MC_<property_name>. Hyphens (-) should be replaced with underscores (_). For example, to set the server-port property, use the MC_server_port environment variable. The Minecraft wiki has a list of all available properties. You can use the docker-compose.yaml file in this repository as a reference to set up your server.
Included docker-compose.yaml file:
services:
java-server:
image: guardcraft-java
restart: unless-stopped
ports:
- 25565:25565
environment:
# Server properties Set Up
# MC_* variables will be replaced in the server.properties file
# Hyphens must be replaced with underscores
MC_gamemode: "survival"
MC_difficulty: "easy"
MC_motd: "Welcome to GuardCraft!"
MC_level_name: "GuardCraft"
MC_level_seed: "-1718501946501227358"This will set up a server in Survival mode, with Easy difficulty, and a Welcome to GuardCraft! message of the day. The server will be named GuardCraft and will use the specified seed to generate the world. You should spawn in an area with a village nearby. If you want a random spawn point, you can comment out or remove the MC_level_seed variable.
To save your world data, it is recommended to use a named volume. This will ensure that every time you run docker compose down and docker compose up, your world data will be preserved.
Start by creating a named volume:
docker volume create guardcraft-worldThen, modify the docker-compose.yaml file to use the named volume as shown:
ports:
- 25565:25565
environment:
MC_gamemode: "survival"
MC_difficulty: "easy"
MC_motd: "Welcome to GuardCraft!"
MC_level_name: "GuardCraft"
MC_level_seed: "-1718501946501227358"
volumes:
- guardcraft-world:/minecraft/world
volumes:
guardcraft-world:
external: trueThe external:true flag tells Docker Compose to use the named volume you created earlier, instead of creating an anonymous volume mount. This will ensure that your world data is saved in the guardcraft-world volume.
The skins folder contains some custom player skins you can use to customize your character.