Common Pods Errors - Startup errors

Giriş

Bazı hatalar şöyle

1. ImagePullBackoff
2. ImageInspectError
3. ErrImagePull
4. ErrImageNeverPull
5. RegistryUnavailable
6. InvalidImageName

Ayrıca FailedScheduling de çok yaygın

Ne Yapmak Lazım

1. kubectl describe pod $POD_NAME | less ile duruma bakılabilir

2. Eğer bir şeyi değiştirip tekrar denemek istersek şöyle yaparız

kubectl edit pod $POD_NAME
# or 
kubectl edit deployment $DEPLOYMENT_NAME

# or if you just want to view the information
kubectl get deployment $DEPLOYMENT_NAME -oyaml

3. loglara bakabiliriz. Şöyle yaparız

kubectl logs $POD_NAME
kubectl logs $POD_NAME -c $CONTAINER_NAME

# or if you want to follow continuous output
kubectl logs -f $POD_NAME

# Another super useful debugging tool is the -p/--previous flag, 
# which you can use in the case that an instance keeps crashing/ 
# there was an unexpected restart.
kubectl logs -p $POD_NAME

ContainerCreating 

Açıklaması şöyle

Generally the pod will be stuck in states like ContainerCreating or if there’s an image issue you might see ImagePullBackoff , possibly indicating the image couldn’t be found or authenticated to.

ImagePullBackOff 

Açıklaması şöyle

This error means K8s is unable to pull the image for one of the containers in the Pod.

Common cause of the error could be one of the following,

1. The Image name is invalid
2. You specified non existing tag for the Image
4. The image that you are trying to pull belongs to a private registry and k8s does not have credentials to access it.

The first two cases can be solved by correcting the image name and tag.

For the last, you should add the credentials to your private registry in a Secret and reference it in your Pods.

FailedScheduling 

nodeSelector veya nodeAffinity kullanılıyorsak olabilir. 

Örnek

kubectl -n <namespace> describe pod <podname> çıktısı şöyledir

Warning FailedScheduling 118s (x26 over 7m43s) default-scheduler 0/53 nodes are available: 53 node(s) didn’t match Pod’s node affinity