5 guides
Reclaim Docker disk space safely: read docker system df, use docker system prune the right way, and understand the -a and --volumes danger before you run it.
Fix Docker's 'bind: address already in use' error: find the listener with ss or lsof, free the port or change the mapping, and bind to 127.0.0.1.
Fix the 'Cannot connect to the Docker daemon' error: check the service is running, fix socket permissions, start Docker Desktop, and verify DOCKER_HOST.
Fix the Docker 'port is already allocated' error: find what's using the port with docker ps, ss, and lsof, then free it or change the mapping.
Pillar Guide
Install Docker on Ubuntu Server the right way: add the official apt repo and GPG key, install docker-ce plus the Compose plugin, and verify it works.