Debugging aplikasi containerized nglibatake inspecting logs, nggoleki shell ing sajroning containers, examining configuration lan state, lan diagnosing masalah umum (crashes, networking, resources). Ngerti cara troubleshoot iku essential practical skill.
docker ps -a
docker logs <container>
docker logs -f -- 100 <container>
docker inspect <container>
docker events
docker logs biasanipun langkah kaping pisanan — iku nudukake application's output lan errors. docker ps -a nudukake manawa container wis exits (lan exit code-nipun).
# run an interactive shell inside a RUNNING container to investigate
docker exec -it <container> bash # or sh (alpine)
# → inspect files, run commands, check the environment, test connectivity from inside
# if the container won't STAY running, override the entrypoint to get a shell
docker run -it --entrypoint sh myimage
docker exec -it ... bash menehi shell sajroning running container — invaluable kanggo inspecting files, checking environment, lan testing connectivity saka perspektif container.
Container EXITS immediately → check `docker logs`; the main process crashed or finished
(a container stops when its main process exits) — check CMD/ENTRYPOINT, errors
CAN'T CONNECT between containers → check they're on the same network; use service NAMES
(not localhost); verify ports; `docker network inspect`
PORT not accessible → check -p mapping; the app must listen on 0.0.0.0 (not 127.0.0.1)
OUT OF MEMORY / killed → check `docker stats`, resource limits (OOMKilled in inspect)
PERMISSION errors → file ownership/user (non-root user vs mounted volume permissions)
IMAGE issues → rebuild without cache (--no-cache); check the build context/.dockerignore
Ngerti cara debug lan troubleshoot Docker containers iku essential practical skill, amarga containerized applications inevitably duwe issues (crashes, connectivity problems, configuration errors) sing kudu diagnosed, lan containerized environment nambahi layer sing merlokake specific debugging techniques.
Fundamental skills — inspecting logs (docker logs, biasanipun langkah pisanan, nudukake application's output lan errors), checking status (docker ps -a nudukake manawa lan kenapa container exits, kalebu exit codes), lan examining configuration/state (docker inspect) — iku cara sampeyan miwiti diagnosing paling issues.
Nggoleki shell sajroning container (docker exec -it ... bash) iku invaluable technique kanggo investigate saka container's perspective — inspecting files, checking environment, lan testing connectivity — lan ngerti cara nggoleki shell malah manawa container ora bakal tetep running (overriding entrypoint) nangani tricky cases.
Paham common issues lan diagnosis-nipun iku particularly valuable: containers exiting immediately (main process crashed utawa finished — checking logs lan CMD/ENTRYPOINT), inter-container connectivity problems (network membership, nggunakake service names ora localhost), ports ora accessible (mapping, lan common gotcha manawa app kudu listen ing 0.0.0.0 ora 127.0.0.1), out-of-memory kills, lan permission errors — iki iku real, recurring problems sing ngerti cara recognize lan fix-ipun nyimpen significant time.
Kamukten containerized applications duwe issues sing kudu debugged, lan kamukten effective troubleshooting (logs, exec into containers, inspect, lan recognizing common failure patterns) iku necessary kanggo diagnose lan resolve-ipun, ngerti cara debug Docker containers iku essential, frequently-applied practical skill kanggo sapa wae running containerized applications, core operational competency sing ngowahi frustrating container problems dadi solvable.