I set up a Harbor registry which worked successfully for a couple of weeks now. For each deployment and namespace I a have a secret with the credentials from my ~/.docker/config.json file to get access to the registry. Since last weekend I was not able to pull images from that registry anymore and I didn't change anything! The cluster is running on GKE v1.12.5 btw.

What works? I can pull and push images from my local machine witch docker.

What does not work? My Kubernetes cluster cannot pull images anymore and runs in a timeout.

Events:
  Type     Reason          Age                  From                                                       Message
  ----     ------          ----                 ----                                                       -------
  Normal   Scheduled       13m                  default-scheduler                                          Successfully assigned k8s-test7/nginx-k8s-test7-6f7b8fdd79-2ffmp to gke-k8s-cloudops-test-default-pool-72fccd21-hrhk
  Normal   SandboxChanged  12m                  kubelet, gke-k8s-cloudops-test-default-pool-72fccd21-hrhk  Pod sandbox changed, it will be killed and re-created.
  Warning  Failed          11m (x3 over 12m)    kubelet, gke-k8s-cloudops-test-default-pool-72fccd21-hrhk  Failed to pull image "core.k8s-harbor-test.my-domain.com/nginx-test/nginx:1.15.10": rpc error: code = Unknown desc = Error response from daemon: Get https://core.k8s-harbor-test.my-domain.com/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
  Warning  Failed          11m (x3 over 12m)    kubelet, gke-k8s-cloudops-test-default-pool-72fccd21-hrhk  Error: ErrImagePull
  Normal   BackOff         11m (x7 over 12m)    kubelet, gke-k8s-cloudops-test-default-pool-72fccd21-hrhk  Back-off pulling image "core.k8s-harbor-test.my-domain.com/nginx-test/nginx:1.15.10"
  Normal   Pulling         10m (x4 over 13m)    kubelet, gke-k8s-cloudops-test-default-pool-72fccd21-hrhk  pulling image "core.k8s-harbor-test.my-domain.com/nginx-test/nginx:1.15.10"
  Warning  Failed          3m2s (x38 over 12m)  kubelet, gke-k8s-cloudops-test-default-pool-72fccd21-hrhk  Error: ImagePullBackOff

deployment.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-k8s-test7
  namespace: k8s-test7
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx-k8s-test7
    spec:
      containers:
      - name: nginx-k8s-test7
        image: core.k8s-harbor-test.my-domain.com/nginx-test/nginx:1.15.10
        volumeMounts:
          - name: webcontent
            mountPath: /usr/share/nginx/html
        ports:
        - containerPort: 80
      volumes:
        - name: webcontent
          configMap:
            name: webcontent
      imagePullSecrets:
      - name: harborcred
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: webcontent
  namespace: k8s-test7
  annotations:
    volume.alpha.kubernetes.io/storage-class: default
spec:
  accessModes: [ReadWriteOnce]
  resources:
    requests:
      storage: 5Gi

The secret "harborcred" is part of every namespace so that the deployment can access it. The secret was created per kubernetes documentation:

https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/

kubectl create secret generic harborcred \
    --from-file=.dockerconfigjson=~/.docker/config.json \
    --type=kubernetes.io/dockerconfigjson \
    --namespace=k8s-test7

Any help would be appreciated!