What steps can you take to resolve a permission denied error in Docker?

Docker is a powerful tool for deploying applications using lightweight, portable containers. However, one of the most common issues users face is the permission denied error. This often happens when you run a Docker command without sudo, for example:

Instead of a list of containers, you might get this Docker socket error:

permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock

This error happens because the Docker service runs as the root user and uses a special file to talk to other programs. If your user doesn't have permission to access that file, Docker commands won’t work. In this guide, we’ll guide you on how to fix the "permission denied" error in Docker.

Simulating the "Permission Denied" Error

Run the following command to list running Docker containers.

As root, this will work. But if you switch to a non-root user (e.g., su - youruser) and try:

You’ll get: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock

How to Fix the Docker Permission Denied Error?

Below are the recommended steps to fix this error.

1. Verify Docker Installation

Before anything else, check that Docker is running correctly:

Make sure the service is active and not failing. You can start the service and check the status using the following commands.

2. Add Your User to the Docker Group

The Docker daemon binds to a Unix socket (/var/run/docker.sock) that’s owned by the docker group. To let your user access it:

Then log out and back in, or run:

Now, log in to the user account on you were getting the error and run the docker ps command.

3. Adjust File and Directory Permissions

Check the permissions of the Docker socket:

You should see something like:

If not, fix it:

4. Check Docker Socket Permissions

If for some reason the Docker socket has incorrect permissions or group ownership after a reboot, consider creating a systemd override:

Then add:

Save and restart Docker:

5. Restart Docker and Verify

Restart the Docker service:

Then log in as your non-root user, and try:

You should no longer see the permission denied error.

Test with a Container docker run hello-world

This tests both your Docker install and that your user has permission.

Conclusion

A "permission denied" error when using Docker means your user doesn't have access to the Docker daemon. By adding the user to the Docker group and checking socket permissions, you can resolve this easily.