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lab 3.2 post simpleapp deployment not working

wherever simpleapp is referenced in future labs i am getting error imagebackoff in pod status and when i describe i am getting error

Warning Failed 14s (x2 over 31s) kubelet, 2b7fb2b29d1c.mylabserver.com Failed to pull image "": rpc error: code = Unknown desc = Error response from daemon: manifest for not found: manifest unknown: manifest unknown

Normal BackOff 0s (x3 over 30s) kubelet, 2b7fb2b29d1c.mylabserver.com Back-off pulling image ""
Warning Failed 0s (x3 over 30s) kubelet, 2b7fb2b29d1c.mylabserver.com Error: ImagePullBackOff

kindly suggest next steps how to debug this issue.



  • serewicz
    serewicz Posts: 1,000


    There are a few reasons this could happen. The most common one I have encountered is when docker is configured on the master but not on the worker. Second most common is a typo in the image name.

    When you run sudo docker image do you see the simpleapp image? If you use sudo docker pull on the master and worker does it work?


  • suser
    suser Posts: 67

    I keep having the same problem after rebooting the master node. Apparently the image needed for try1 deployment do not persists on reboot.

    vio@kmaster:~$ kubectl get po
    nginx-b68dd9f75-vq6vr 1/1 Running 1 21h
    registry-cbc9b4779-5qqq5 1/1 Running 5 2d23h
    try1-85f7fc6ddf-8m766 0/1 ImagePullBackOff 0 20h
    try1-85f7fc6ddf-9lbc7 0/1 ImagePullBackOff 0 20h
    try1-85f7fc6ddf-c958k 0/1 ImagePullBackOff 0 20h
    try1-85f7fc6ddf-fkxg5 0/1 ImagePullBackOff 0 20h
    try1-85f7fc6ddf-mkmgs 0/1 ImagePullBackOff 0 20h
    try1-85f7fc6ddf-x5snl 0/1 ErrImagePull 0 20h

    The repository looks good and running.
    What I have to do is to push again the needed image:
    sudo docker push

    After this the try1- pods start one after another in few seconds.

    What to do to fix the image persistence?


  • chrispokorni
    chrispokorni Posts: 2,164

    Hi @suser,

    The registry is cleaned up at reboot because the Persistent Volume uses /tmp/... as the hostPath: . You can edit your vol1.yaml and vol2.yaml manifests and update the path: property found under hostPath: to point to a different host directory.


  • Hi @chrispokorni to fix persistence do we need to create that directory on container using exec please advise.
    thanks santosh

  • Hi @santoshsub123,

    Creating the hostPath directory anywhere on the Node/host is fine, as long as it is not in /tmp.



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