Kubernetes: comment déboguer CrashLoopBackOff
J'ai la configuration suivante:
Une image de menu fixe omg/telperion sur concentrateur de docker Un cluster kubernetes (avec 4 nœuds, chacun avec environ 50 Go de RAM) et beaucoup de ressources
J'ai suivi des tutoriels pour extraire des images de dockerhub à kubernetes
SERVICE_NAME=telperion
DOCKER_SERVER="https://index.docker.io/v1/"
DOCKER_USERNAME=username
DOCKER_PASSWORD=password
DOCKER_EMAIL="[email protected]"
# Create secret
kubectl create secret docker-registry dockerhub --docker-server=$DOCKER_SERVER --docker-username=$DOCKER_USERNAME --docker-password=$DOCKER_PASSWORD --docker-email=$DOCKER_EMAIL
# Create service yaml
echo "apiVersion: v1 \n\
kind: Pod \n\
metadata: \n\
name: ${SERVICE_NAME} \n\
spec: \n\
containers: \n\
- name: ${SERVICE_NAME} \n\
image: omg/${SERVICE_NAME} \n\
imagePullPolicy: Always \n\
command: [ \"echo\",\"done deploying $SERVICE_NAME\" ] \n\
imagePullSecrets: \n\
- name: dockerhub" > $SERVICE_NAME.yaml
# Deploy to kubernetes
kubectl create -f $SERVICE_NAME.yaml
Ce qui a pour conséquence que le pod entre dans un CrashLoopBackoff
docker run -it -p8080:9546 omg/telperion fonctionne bien.
Donc, ma question est est-ce un debug-capable?, Si oui, comment puis-je déboguer ceci?
Quelques logs:
kubectl get nodes
NAME STATUS AGE VERSION
k8s-agent-adb12ed9-0 Ready 22h v1.6.6
k8s-agent-adb12ed9-1 Ready 22h v1.6.6
k8s-agent-adb12ed9-2 Ready 22h v1.6.6
k8s-master-adb12ed9-0 Ready,SchedulingDisabled 22h v1.6.6
.
kubectl get pods
NAME READY STATUS RESTARTS AGE
telperion 0/1 CrashLoopBackOff 10 28m
.
kubectl describe pod telperion
Name: telperion
Namespace: default
Node: k8s-agent-adb12ed9-2/10.240.0.4
Start Time: Wed, 21 Jun 2017 10:18:23 +0000
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.244.1.4
Controllers: <none>
Containers:
telperion:
Container ID: docker://c2dd021b3d619d1d4e2afafd7a71070e1e43132563fdc370e75008c0b876d567
Image: omg/telperion
Image ID: docker-pullable://omg/telperion@sha256:c7e3beb0457b33cd2043c62ea7b11ae44a5629a5279a88c086ff4853828a6d96
Port:
Command:
echo
done deploying telperion
State: Waiting
Reason: CrashLoopBackOff
Last State: Terminated
Reason: Completed
Exit Code: 0
Started: Wed, 21 Jun 2017 10:19:25 +0000
Finished: Wed, 21 Jun 2017 10:19:25 +0000
Ready: False
Restart Count: 3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-n7ll0 (ro)
Conditions:
Type Status
Initialized True
Ready False
PodScheduled True
Volumes:
default-token-n7ll0:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-n7ll0
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: <none>
Events:
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
1m 1m 1 default-scheduler Normal Scheduled Successfully assigned telperion to k8s-agent-adb12ed9-2
1m 1m 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Created Created container with id d9aa21fd16b682698235e49adf80366f90d02628e7ed5d40a6e046aaaf7bf774
1m 1m 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Started Started container with id d9aa21fd16b682698235e49adf80366f90d02628e7ed5d40a6e046aaaf7bf774
1m 1m 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Started Started container with id c6c8f61016b06d0488e16bbac0c9285fed744b933112fd5d116e3e41c86db919
1m 1m 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Created Created container with id c6c8f61016b06d0488e16bbac0c9285fed744b933112fd5d116e3e41c86db919
1m 1m 2 kubelet, k8s-agent-adb12ed9-2 Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "telperion" with CrashLoopBackOff: "Back-off 10s restarting failed container=telperion pod=telperion_default(f4e36a12-566a-11e7-99a6-000d3aa32f49)"
1m 1m 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Started Started container with id 3b911f1273518b380bfcbc71c9b7b770826c0ce884ac876fdb208e7c952a4631
1m 1m 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Created Created container with id 3b911f1273518b380bfcbc71c9b7b770826c0ce884ac876fdb208e7c952a4631
1m 1m 2 kubelet, k8s-agent-adb12ed9-2 Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "telperion" with CrashLoopBackOff: "Back-off 20s restarting failed container=telperion pod=telperion_default(f4e36a12-566a-11e7-99a6-000d3aa32f49)"
1m 50s 4 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Pulling pulling image "omg/telperion"
47s 47s 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Started Started container with id c2dd021b3d619d1d4e2afafd7a71070e1e43132563fdc370e75008c0b876d567
1m 47s 4 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Pulled Successfully pulled image "omg/telperion"
47s 47s 1 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Normal Created Created container with id c2dd021b3d619d1d4e2afafd7a71070e1e43132563fdc370e75008c0b876d567
1m 9s 8 kubelet, k8s-agent-adb12ed9-2 spec.containers{telperion} Warning BackOff Back-off restarting failed container
46s 9s 4 kubelet, k8s-agent-adb12ed9-2 Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "telperion" with CrashLoopBackOff: "Back-off 40s restarting failed container=telperion pod=telperion_default(f4e36a12-566a-11e7-99a6-000d3aa32f49)"
Edit 1: Erreurs signalées par le kubelet sur le maître:
journalctl -u kubelet
.
Jun 21 10:28:49 k8s-master-ADB12ED9-0 docker[1622]: E0621 10:28:49.798140 1809 fsHandler.go:121] failed to collect filesystem stats - rootDiskErr: du command failed on /var/lib/docker/overlay/5cfff16d670f2df6520360595d7858fb5d16607b6999a88e5dcbc09e1e7ab9ce with output
Jun 21 10:28:49 k8s-master-ADB12ED9-0 docker[1622]: , stderr: du: cannot access '/var/lib/docker/overlay/5cfff16d670f2df6520360595d7858fb5d16607b6999a88e5dcbc09e1e7ab9ce/merged/proc/13122/task/13122/fd/4': No such file or directory
Jun 21 10:28:49 k8s-master-ADB12ED9-0 docker[1622]: du: cannot access '/var/lib/docker/overlay/5cfff16d670f2df6520360595d7858fb5d16607b6999a88e5dcbc09e1e7ab9ce/merged/proc/13122/task/13122/fdinfo/4': No such file or directory
Jun 21 10:28:49 k8s-master-ADB12ED9-0 docker[1622]: du: cannot access '/var/lib/docker/overlay/5cfff16d670f2df6520360595d7858fb5d16607b6999a88e5dcbc09e1e7ab9ce/merged/proc/13122/fd/3': No such file or directory
Jun 21 10:28:49 k8s-master-ADB12ED9-0 docker[1622]: du: cannot access '/var/lib/docker/overlay/5cfff16d670f2df6520360595d7858fb5d16607b6999a88e5dcbc09e1e7ab9ce/merged/proc/13122/fdinfo/3': No such file or directory
Jun 21 10:28:49 k8s-master-ADB12ED9-0 docker[1622]: - exit status 1, rootInodeErr: <nil>, extraDiskErr: <nil>
Edit 2: plus de logs
kubectl logs $SERVICE_NAME -p
done deploying telperion
Vous pouvez accéder aux journaux de vos pods avec
kubectl logs [podname] -p
l'option -p lira les journaux de l'instance précédente (bloquée)
Si le crash provient de l'application, vous devriez y avoir des journaux utiles.