X11 in docker on macOS

x11_docker_mac.md

To forward X11 from inside a docker container to a host running macOS

1. Install XQuartz: https://www.xquartz.org/
2. Launch XQuartz. Under the XQuartz menu, select Preferences
3. Go to the security tab and ensure "Allow connections from network clients" is checked.
4. Run xhost + ${hostname} to allow connections to the macOS host *
5. Setup a HOSTNAME env var export HOSTNAME=`hostname`*
6. Add the following to your docker-compose:

  environment:
  - DISPLAY=${HOSTNAME}:0
  volumes:
  - /tmp/.X11-unix:/tmp/.X11-unix

_{* It should be noted that steps 4 and 5 can be automated to run everytime XQuartz starts, but that's outside of the scope of this gist}

For those arriving from google like me: 2024 Dockerfile and compose.yaml for MacOS host:

FROM ubuntu:latest

# Install X11 and sample x11 apps
RUN apt-get update && \
    apt-get install -y x11-apps

# Open xclock on startup
CMD ["xclock"]

services:
  gui-app:
    build: .
    environment:
      - DISPLAY=host.docker.internal:0
    volumes:
      - /tmp/.X11-unix:/tmp/.X11-unix

Before docker compose up, install xquartz and do enable network connections on settings security tab.

I just wanted to post and confirm this worked for me in February 2024 on an m2 macbook. Thank you!

Somehow it didn't work on my M2 MacOS :(

Error: Can't open display: host.docker.internal:0

Any suggestion?

There shouldn't be a need of using "DISPLAY=host.docker.internal:0" and mounting the "/tmp/.X11-unix" socket file. I was able to make this work with just the DISPLAY envvar and enabling network connections and disabling connections auth in XQuartz settings.
Nevertheless, I think the ideal would be to just use the "/tmp/.X11-unix" file instead of network connections. I'm not being able to make this work even though the file seems to be correctly mounted inside the container.

@ldipenti FTR I had to include the host.docker.internal:0, in 2024. I'm on a MacBook Pro 2024 m3 version.

Here is a working Dockerfile and Dockercompose:

FROM openjdk:11

# Install necessary packages for X11 or for your app
RUN apt-get update && apt-get install -y \
    libxext6 \
    libxrender1 \
    libxtst6 \
    x11-apps

# Set the working directory
WORKDIR /app

# Copy the source code into the container
COPY src /app/src
COPY dist/lib /app/lib

# Compile the Java application
RUN javac -cp "/app/lib/*" -d /app/bin /app/src/*.java

# Set the DISPLAY environment variable for X11 forwarding
ENV DISPLAY host.docker.internal:0

# Run the compiled Java application
CMD ["java", "-cp", "/app/bin:/app/lib/*", "MainClass"]

version: '3'
services:
  java-app:
    build: .
    image: java-app
    container_name: java-app-container
    environment:
      - _JAVA_OPTIONS="-Dsun.java2d.xrender=false"

I added the _JAVA_OPTIONS stuff cause I was getting some weird color errors on my swing ui.