Automatic merge from submit-queue (batch tested with PRs 65052, 65594). 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>.
Derive kubelet serving certificate CSR template from node status addresses
xref https://github.com/kubernetes/features/issues/267fixes#55633
Builds on https://github.com/kubernetes/kubernetes/pull/65587
* Makes the cloud provider authoritative when recording node status addresses
* Makes the node status addresses authoritative for the kube-apiserver determining how to speak to a kubelet (stops paying attention to the hostname label when determining how to reach a kubelet, which was only done to support kubelets < 1.5)
* Updates kubelet certificate rotation to be driven from node status
* Avoids needing to compute node addresses a second time, and differently, in order to request serving certificates.
* Allows the kubelet to react to changes in its status addresses by updating its serving certificate
* Allows the kubelet to be driven by external cloud providers recording node addresses on the node status
test procedure:
```sh
# setup
export FEATURE_GATES=RotateKubeletServerCertificate=true
export KUBELET_FLAGS="--rotate-server-certificates=true --cloud-provider=external"
# cleanup from previous runs
sudo rm -fr /var/lib/kubelet/pki/
# startup
hack/local-up-cluster.sh
# wait for a node to register, verify it didn't set addresses
kubectl get nodes
kubectl get node/127.0.0.1 -o jsonpath={.status.addresses}
# verify the kubelet server isn't available, and that it didn't populate a serving certificate
curl --cacert _output/certs/server-ca.crt -v https://localhost:10250/pods
ls -la /var/lib/kubelet/pki
# set an address on the node
curl -X PATCH http://localhost:8080/api/v1/nodes/127.0.0.1/status \
-H "Content-Type: application/merge-patch+json" \
--data '{"status":{"addresses":[{"type":"Hostname","address":"localhost"}]}}'
# verify a csr was submitted with the right SAN, and approve it
kubectl describe csr
kubectl certificate approve csr-...
# verify the kubelet connection uses a cert that is properly signed and valid for the specified hostname, but NOT the IP
curl --cacert _output/certs/server-ca.crt -v https://localhost:10250/pods
curl --cacert _output/certs/server-ca.crt -v https://127.0.0.1:10250/pods
ls -la /var/lib/kubelet/pki
# set an hostname and IP address on the node
curl -X PATCH http://localhost:8080/api/v1/nodes/127.0.0.1/status \
-H "Content-Type: application/merge-patch+json" \
--data '{"status":{"addresses":[{"type":"Hostname","address":"localhost"},{"type":"InternalIP","address":"127.0.0.1"}]}}'
# verify a csr was submitted with the right SAN, and approve it
kubectl describe csr
kubectl certificate approve csr-...
# verify the kubelet connection uses a cert that is properly signed and valid for the specified hostname AND IP
curl --cacert _output/certs/server-ca.crt -v https://localhost:10250/pods
curl --cacert _output/certs/server-ca.crt -v https://127.0.0.1:10250/pods
ls -la /var/lib/kubelet/pki
```
```release-note
* kubelets that specify `--cloud-provider` now only report addresses in Node status as determined by the cloud provider
* kubelet serving certificate rotation now reacts to changes in reported node addresses, and will request certificates for addresses set by an external cloud provider
```
337dfe0a9c