Running GUI Applications in Docker

Introduction

Docker has revolutionized the way we develop and deploy applications, offering consistency and portability across different environments. However, running graphical user interface (GUI) applications within Docker containers presents unique challenges. This tutorial will guide you through the process of running GUI applications like Rviz or Gazebo in Docker, addressing common issues and providing practical solutions.

The Challenge of GUI in?Docker

Docker containers are designed to be lightweight and isolated, which can make it difficult to run GUI applications that require access to the host’s display server. Users often encounter issues such as:

1. No display output
2. Access denied errors
3. Performance problems
4. X11 forwarding complications

These challenges arise because Docker containers, by default, don’t have access to the host’s X11 socket, which is necessary for displaying GUI applications.

Solution: Running GUI Applications in?Docker

Let’s break down the process step-by-step:

Running the Docker Container:

docker run --net=host --env="DISPLAY=$DISPLAY" --env="QT_X11_NO_MITSHM=1" --volume="/tmp/.X11-unix:/tmp/.X11-unix:rw" --device=/dev/dri:/dev/dri --group-add video --env="XAUTHORITY=$XAUTH" --volume="$XAUTH:$XAUTH" --name=<container name> -it <image name>        

This command is packed with options to enable GUI applications:

• --net=host: Uses the host's network stack inside the container.
• --env="DISPLAY=$DISPLAY": Passes the host's DISPLAY environment variable to the container.
• --env="QT_X11_NO_MITSHM=1": Disables MIT-SHM extension, which can cause issues with some applications.
• --volume="/tmp/.X11-unix:/tmp/.X11-unix:rw": Mounts the X11 socket inside the container.
• --device=/dev/dri:/dev/dri: Gives the container access to the host's DRI (Direct Rendering Infrastructure).
• --group-add video: Adds the container's user to the video group.
• --env="XAUTHORITY=$XAUTH" --volume="$XAUTH:$XAUTH": Sets up X11 authentication.

Run the following inside the container

Updating and Installing Dependencies:

apt-get update
apt-get -y install libgl1-mesa-glx libgl1-mesa-dri && rm -rf /var/lib/apt/lists/        

These commands update the package lists and install necessary OpenGL libraries.

Setting Up GUI Support:

apt-get update && apt-get install -y xauth x11-apps        

This installs X11 authentication and some basic X11 applications.

Checking the System Version:

lsb_release -a        

This command displays the version information of the Docker system.

Run the following in your local?machine

Granting Docker Access to X Server:

sudo xhost +local:docker        

Run this command on the host to allow Docker containers to access the X server.

Managing the Container:

docker start <container>
docker exec -it <container> bash        

These commands start a stopped container and execute an interactive bash shell in it.

Best Practices and Considerations:

1. Security: Be cautious when using xhost +local:docker as it can pose security risks. Consider using more restrictive options in production environments.
2. Performance: GUI applications in Docker may have slightly lower performance compared to native applications.
3. Compatibility: Not all GUI applications will work perfectly in Docker. Test thoroughly and be prepared to troubleshoot.
4. Persistence: Consider using Docker volumes to persist data and configurations for your GUI applications.

Conclusion

Running GUI applications in Docker opens up new possibilities for containerized development and testing, especially in fields like robotics where tools like RViz and Gazebo are essential. While it requires some additional setup, the benefits of consistency and portability make it a valuable skill for developers and engineers.

By following this guide, you should now be able to run GUI applications in your Docker containers, enhancing your development workflow and expanding the capabilities of your containerized environments.

References