Kubernetes: expired certificate

Question

Our Kubernetes 1.6 cluster had certificates generated when the cluster was built on April 13th, 2017.

On December 13th, 2017, our cluster was upgraded to version 1.8

Answer 1

On k8s 1.7 I faced a similar problem (x509 expired error included inside /var/log/kube-apiserver.log) and could not find any certificate expired. We decided to restart only the apiserver docker on the master node. It resolved the problem.

$ sudo docker ps -a | grep apiserver
af99f816c7ec        gcr.io/google_containers/kube-apiserver@sha256:53b987e5a2932bdaff88497081b488e3b56af5b6a14891895b08703129477d85               "/bin/sh -c '/usr/loc"   15 months ago       Up 19 hours                                     k8s_kube-apiserver_kube-apiserver-ip-xxxxxc_0
40f3a18050c3        gcr.io/google_containers/pause-amd64:3.0                                                                                      "/pause"                 15 months ago       Up 15 months                                    k8s_POD_kube-apiserver-ip-xxxc_0
$ sudo docker restart af99f816c7ec
af99f816c7ec
$