#Linux

Docker permission denied on docker.sock: the Right Fix (and Its Security Cost)

docker commands fail with permission denied while trying to connect to the Docker daemon socket? The cause: your user isn't in the docker group. One-step fix with usermod -aG, the newgrp trick to avoid re-login, why chmod 777 is a trap, and why docker group membership equals passwordless root — plus the rootless alternative.

Docker no space left on device: the Complete Cleanup Ladder, Safe to Aggressive

Docker build or run failing with no space left on device? Dangling images, stopped containers, build cache, and unbounded container logs — see exactly who eats the disk with docker system df. The prune ladder from container prune to system prune -a, the --volumes danger zone, and the log-rotation config that stops it coming back.