Kutatua matatizo ya programu zenye konteina kunahusisha kuchunguza logs, kupata shell ndani ya kontena, kuchunguza configuration na state, na kubaini matatizo ya kawaida (crashes, networking, resources). Kujua jinsi ya kutatanisha matatizo ni ujuzi muhimu wa vitendo.
docker ps -a
docker logs <container>
docker logs -f -- 100 <container>
docker inspect <container>
docker events
docker logs kawaida ni hatua ya kwanza — inaonyesha matokeo na hitilafu ya programu. docker ps -a inaonyesha kama kontena ilijibu (na code yake ya kutoka).
# 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 inatoa shell ndani ya kontena inayofanya kazi — sana muhimu kwa kuchunguza faili, kuangalia mazingira, na kujaribu uunganisho kutoka mtazamo wa kontena.
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
Kujua jinsi ya kutatua matatizo na kutatanisha kontena za Docker ni ujuzi muhimu wa vitendo, kwa sababu programu zenye konteina bila shaka zina matatizo (crashes, matatizo ya uunganisho, hitilafu za usanidi) ambayo lazima kubaini, na mazingira ya konteina yanaongeza tabaka linalohitaji mbinu maalum za kutatanisha.
Ujuzi wa msingi — kuchunguza logs (docker logs, kawaida hatua ya kwanza, inayoonyesha matokeo na hitilafu ya programu), kuangalia status (docker ps -a inayoonyesha kama na kwa nini kontena ilijibu, ikiwa ni pamoja na exit codes), na kuchunguza configuration/state (docker inspect) — ndio jinsi unavyoanza kubaini matatizo mengi.
Kupata shell ndani ya kontena (docker exec -it ... bash) ni mbinu sana muhimu kwa kuchunguza kutoka mtazamo wa kontena — kuchunguza faili, kuangalia mazingira, na kujaribu uunganisho — na kujua jinsi ya kupata shell hata wakati kontena haitasimama (kuoza entrypoint) kunamkuta kesi ngumu.
Kuelewa matatizo ya kawaida na utambuzi wao ni muhimu sana: kontena zinajibu mara moja (mchakato mkuu ulianguka au kuishia — kuangalia logs na CMD/ENTRYPOINT), matatizo ya uunganisho kati ya kontena (uanachama wa mtandao, kutumia majina ya huduma si localhost), bandari haziendelewi (mapping, na tatizo linalofahamika kwamba programu lazima sikilize kwenye 0.0.0.0 si 127.0.0.1), out-of-memory kills, na hitilafu za ruhusa — haya ni matatizo ya kweli na ya kurudiwa ambayo kujua jinsi ya kutambua na kurekebisha huokoa wakati muhimu.
Kwa sababu programu zenye konteina zina matatizo ambayo lazima kutatanishwe, na kwa sababu kutatanisha kwa ufanisi (logs, exec ndani ya kontena, inspect, na kutambua mifumo ya kushindwa) ni muhimu kubaini na kutatua, kujua jinsi ya kutatua matatizo ya Docker kontena ni ujuzi muhimu wa vitendo unaotumika mara kwa mara kwa kila mtu anayefanya kazi na programu zenye konteina, ujuzi wa operesheni muhimu unaogeuka matatizo ya kontena yenye matatizo kuwa yaliyotatuliwa.