When I have a kubernetes cluster with multiple control nodes and delete one of these, the whole API server does not seem to be available anymore.
In this setup I want to scale down from two to one control node but end up rendering the cluster unusable:
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master1 Ready master 5d20h v1.18.6
worker1 Ready <none> 5d19h v1.18.6
master2 Ready master 19h v1.18.6
$ kubectl drain master2 --ignore-daemonsets
node/master2 cordoned
WARNING: ignoring DaemonSet-managed Pods: kube-system/calico-node-hns7p, kube-system/kube-proxy-vk6t7
node/master2 drained
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master1 Ready master 5d20h v1.18.6
worker1 Ready <none> 5d20h v1.18.6
master2 Ready,SchedulingDisabled master 19h v1.18.6
$ kubectl delete node master2
node "master2" deleted
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master1 Ready master 5d20h v1.18.6
worker1 Ready <none> 5d20h v1.18.6
$ ssh master2
$ sudo kubeadm reset
[reset] Reading configuration from the cluster...
[reset] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
W0811 10:24:49.750898 7159 reset.go:99] [reset] Unable to fetch the kubeadm-config ConfigMap from cluster: failed to get node registration: failed to get corresponding node: nodes "master2" not found
[reset] WARNING: Changes made to this host by 'kubeadm init' or 'kubeadm join' will be reverted.
[reset] Are you sure you want to proceed? [y/N]: y
[preflight] Running pre-flight checks
W0811 10:24:51.487912 7159 removeetcdmember.go:79] [reset] No kubeadm config, using etcd pod spec to get data directory
[reset] Stopping the kubelet service
[reset] Unmounting mounted directories in "/var/lib/kubelet"
[reset] Deleting contents of config directories: [/etc/kubernetes/manifests /etc/kubernetes/pki]
[reset] Deleting files: [/etc/kubernetes/admin.conf /etc/kubernetes/kubelet.conf /etc/kubernetes/bootstrap-kubelet.conf /etc/kubernetes/controller-manager.conf /etc/kubernetes/scheduler.conf]
[reset] Deleting contents of stateful directories: [/var/lib/etcd /var/lib/kubelet /var/lib/dockershim /var/run/kubernetes /var/lib/cni]
The reset process does not clean CNI configuration. To do so, you must remove /etc/cni/net.d
The reset process does not reset or clean up iptables rules or IPVS tables.
If you wish to reset iptables, you must do so manually by using the "iptables" command.
If your cluster was setup to utilize IPVS, run ipvsadm --clear (or similar)
to reset your system's IPVS tables.
The reset process does not clean your kubeconfig files and you must remove them manually.
Please, check the contents of the $HOME/.kube/config file.
$ exit
$ kubectl get nodes
Error from server: etcdserver: request timed out
$ kubectl cluster-info
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
The connection to the server master1:6443 was refused - did you specify the right host or port?
What's missing here? Or how else is removing a control plane node different from removing a worker node? Pointers are appreciated.