Kubeadm: master node is never ready

Question

I am following a blog post to configure a cluster of kubernetes with kubeadm. So I have a Virtualbox created using a bridge network and just following the instructions.

I initially just made kubeadm init and it did not work (NotReady wizard). So I thought maybe an older version might work better.

So i did

 kubeadm init --kubernetes-version v1.6.2 

It ended pretty quickly. But kubeadm get nodes always returns:

 master NotReady 4m v1.6.3 

I checked the downloaded docker images and they look like this:

 gcr.io/google_containers/kube-proxy-amd64 v1.6.2 7a1b61b8f5d4 4 weeks ago 109.2 MB gcr.io/google_containers/kube-controller-manager-amd64 v1.6.2 c7ad09fe3b82 4 weeks ago 132.7 MB gcr.io/google_containers/kube-apiserver-amd64 v1.6.2 e14b1d5ee474 4 weeks ago 150.5 MB gcr.io/google_containers/kube-scheduler-amd64 v1.6.2 b55f2a2481b9 4 weeks ago 76.76 MB gcr.io/google_containers/etcd-amd64 3.0.17 243830dae7dd 12 weeks ago 168.9 MB gcr.io/google_containers/pause-amd64 3.0 99e59f495ffa 12 months ago 746.9 kB 

and docker ps output shows that the following containers use pause

 k8s_POD_kube-scheduler-master_kube-system_e4c05f51e4e89758e2fb58eb9c457e66_2 k8s_POD_kube-controller-manager-master_kube-system_14cceb4cae4afafe5d2872cedc46b03f_2 k8s_POD_etcd-master_kube-system_7075157cfd4524dbe0951e00a8e3129e_2 k8s_POD_kube-apiserver-master_kube-system_bd46883c0ce86694060fb2924470cfa7_2 

I am a bit confused:

• In what situation does the node master enter the Ready state?

• Why is there a difference between the version I requested (and the docker image tag) and the version reported by kubeadm ?

Answer 1

It seems you have not installed Network Overlay. For example, if for flannelde it would be like this:

 kubectl create -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel-rbac.yml kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml 

After that, your node should change to Finish.