#operations

docker run to docker-compose: The Complete Migration Guide (with Flag Map)

Migrate docker run commands to docker-compose.yml: five advantages of compose over raw run, a flag-by-flag mapping table (ports, volumes, env, restart, networks), the classic pitfalls (bare -e passthrough, anonymous volumes, --rm semantics), and an online converter that runs locally in your browser.

docker pull access denied: 5 Reasons Image Pulls Get Rejected (and the Fix)

docker pull fails with pull access denied for xxx, repository does not exist or may require docker login? Covers misspelled image names, missing tags, private registry login, Docker Hub rate limits, and registry mirrors for mainland China networks — with a one-minute triage flow.

Docker port is already allocated: Finding and Freeing the Taken Port

docker run fails with port is already allocated or bind: address already in use? The host-side port you mapped is taken — by another container's docker-proxy or a host process. How to tell the two apart, the compose project-name collision scenario, and why 127.0.0.1 and a specific IP binding can coexist.

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.

docker manifest unknown: 4 Reasons the Tag Can't Be Found

docker pull reports manifest for xxx:tag not found or manifest unknown? Covers tag typos, the latest-tag trap, renamed official images, and architecture mismatches (arm64/amd64 manifests) — with docker manifest inspect and the Hub Tags API for verification.

Executable File Not Found: 4 Reasons Docker Containers Exit Instantly (incl. exec format error)

Container fails with OCI runtime exec failed: executable file not found or standard_init_linux.go errors? Covers Windows CRLF breaking shebangs, ENTRYPOINT shell vs exec form, PATH and relative paths, and architecture mismatches — with docker inspect and --entrypoint debugging.

Cannot connect to the Docker daemon — 5 Reasons and How to Diagnose Each

docker ps fails with Cannot connect to the Docker daemon at unix:///var/run/docker.sock? Covers the Linux service not running, Docker Desktop not started, WSL2 integration reset, daemon.json syntax errors killing the daemon, wrong docker context, and missing rootless DOCKER_HOST — with journalctl diagnostics.

Container Name Is Already in Use: Resolving the Conflict Error

docker run fails with Conflict. The container name /xxx/ is already in use? An old container with the same name still exists — stopped containers keep their names too. Covers finding the squatter with docker ps -a, rm -f to free it, compose down for project leftovers, --rm for one-shot runs, and restart-policy resurrections.