Although this problem has been a long time ago, I also encountered this problem. Finally, I checked that hook-image-awaiter could not access the k8s api https://kubernetes.default.svc:443/apis/apps/v1/namespaces/jhub/daemonsets/hook-image-puller, so I suspected that there was a problem with the k8s dns. After deleting the two coredns pods in the k8s cluster, jupyterhub started normally.