Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Kubeadm ha upgrade
**What this PR does / why we need it**:
This PR implements one of the actions defined by https://github.com/kubernetes/kubeadm/issues/751 (checklist form implementing HA in kubeadm). see [KEP 0015](https://github.com/kubernetes/community/blob/master/keps/sig-cluster-lifecycle/0015-kubeadm-join-master.md) for more context
With this PR, kubeadm implements a new command `kubeadm upgrade node experimental-control-plane` that managed upgrade of control plane components on a secondary control plane instance.
The entire workflow in case of HA clusters will be:
- Upgrade the control plane
- run `kubeadm upgrade apply` on a first control plane instance
- run `kubeadm upgrade node experimental-control-plane` on secondary control plane instances
- Upgrade nodes
**Special notes for your reviewer**:
/CC @timothysc @luxas @chuckha @kubernetes/sig-cluster-lifecycle-pr-reviews
**Release note**:
```
kubeadm now has the `kubeadm upgrade node experimental-control-plane` command for upgrading secondary control plane instances created with `kubeadm join --experimental-control-plane`.
```
This follows the pattern `kubectl` uses for logging.
There are two remaining glog.Infof call that cannot be removed easily.
One glog call comes from kubelet validation which calls features.SetFromMap.
The other comes from test/e2e during kernel validation.
Mostly fixeskubernetes/kubeadm#852
Signed-off-by: Chuck Ha <ha.chuck@gmail.com>
