Kubernetes: how to debug CrashLoopBackOff

ixaxaar :

I have the following setup:

A docker image omg/telperion on docker hub A kubernetes cluster (with 4 nodes, each with ~50GB RAM) and plenty resources

I followed tutorials to pull images from dockerhub to 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

Which results in the pod going into a CrashLoopBackoff

docker run -it -p8080:9546 omg/telperion works fine.

So my question is Is this debug-able?, if so, how do i debug this?

Some 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: Errors reported by kubelet on master:

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: more logs

kubectl logs $SERVICE_NAME -p                                                                                                    
done deploying telperion
Fabien :

You can access the logs of your pods with

kubectl logs [podname] -p

the -p option will read the logs of the previous (crashed) instance

If the crash comes from the application, you should have useful logs in there.

Collected from the Internet

Please contact [email protected] to delete if infringement.

edited at
0

Comments

0 comments
Login to comment

Related

Kubernetes CrashLoopBackOff

How can I resolve kubernetes CrashLoopBackOff problem?

coredns crashloopbackoff in kubernetes

Kubernetes CrashLoopBackOff default timing

Kubernetes Crashloopbackoff With Minikube

Elasticsearch Kubernetes CrashLoopBackOff

httpd Docker image CrashLoopBackOff on Kubernetes

Redeploy statefulset with CrashLoopBackOff status in kubernetes

CrashLoopBackOff when args are added in Kubernetes

CrashloopBackOff on Pod in Kubernetes(on GCP with Jenkins)

Kubernetes Dashboard CrashLoopBackOff, Get error "connect: no route to host", How could I fix it?

pod with React app failing with with status CrashLoopBackOff on kubernetes

Why am I getting a CrashLoopBackOff on this kubernetes example?

kubernetes ingress-controller CrashLoopBackOff Error

kubernetes: overriding container command caused CrashLoopBackOff

How to debug Unknown field error in Kubernetes?

How to debug when Kubernetes nodes are in 'Not Ready' state

how to debug a CommClosedError in Dask Gateway deployed in Kubernetes

Azure kubernetes - How to debug the application deployed?

How do I debug this Kubernetes coreDNS error?

How to debug mTLS communication with istio in kubernetes?

kubernetes pod crashloopbackoff when python script execute in pod

CrashLoopBackOff Error when deploying Django app on GKE (Kubernetes)

How to debug Kotlin applications running in Kubernetes pods in IntelliJ?

How to debug ABAC to RBAC transition in a GKE kubernetes cluster?

How to debug a Kubernetes service endpoint that isn't serving correctly?

How do you debug python code with kubernetes and skaffold?

How to debug Kubernetes nginx Ingress redirection from HTTP to HTTPS

How to automatically stop rolling update when CrashLoopBackOff?