Docker: permission denied while trying to connect to the daemon socket

What the message looks like

permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get "http://%2Fvar%2Frun%2Fdocker.sock/v1.47/containers/json": dial unix /var/run/docker.sock: connect: permission denied

Common causes

• Your user is not in the docker group.
• You were added to the group, but your current session still has the old group list.
• The permissions of /var/run/docker.sock were changed.
• A script or CI job runs as a different user than you tested with.
• With rootless Docker, the client points to the wrong socket.

Check

1. Which groups does your session have?
   idCopy
2. Who owns the socket?
   ls -l /var/run/docker.sockCopy
3. Is the daemon running at all?
   systemctl status dockerCopy

Fix

• Add your user to the group: sudo usermod -aG docker $USER.
• Log out and in again, or start a shell with the new group: newgrp docker.
• For a quick one-off, run the command with sudo.
• For CI or services, add the service user to the group and restart the service.
• Prefer rootless Docker or Podman if you do not want to hand out root-equivalent rights.

FAQ

Is adding a user to the docker group safe?

It is equivalent to giving that user root rights on the host, because a container can mount any directory. Do it only for people you trust as admins.

What if the message says it cannot connect to the daemon at all?

That is a different error: the Docker service is not running. Start it with systemctl start docker and read the journal if it fails.