- kubeadm: `kubeadm upgrade plan` now supports `--etcd-upgrade` flag to control whether the etcd upgrade plan should be displayed. Add an `EtcdUpgrade` field into `UpgradeConfiguration.Plan` for v1beta4. ([#130023](https://github.com/kubernetes/kubernetes/pull/130023), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]

(N-3). This aligns with the recent change made by SIG Architecture that extends the support skew between the control plane and kubelets. Tolerate this new kubelet skew for the commands `init`, `join` and `upgrade`. Note that if the `kubeadm` user applies a control plane version that is older than the `kubeadm` version (N-1 maximum) then the skew between the kubelet and control plane would become a maximum of N-2. ([#120825](https://github.com/kubernetes/kubernetes/pull/120825), [@pacoxu](https://github.com/pacoxu))...

Kubernetes 1.8 adds the apps/v1beta2 group and version, which now consists of the
DaemonSet, Deployment, ReplicaSet and StatefulSet kinds. This group and version are part
of the Kubernetes Workloads API. We plan to move them to v1 in an upcoming release, so you might want to plan your migration accordingly.

For more information, see [the issue that describes this work in detail](https://github.com/kubernetes/enhancements/issues/353)

*   kube-apiserver: `--ssh-user` and `--ssh-keyfile` are now deprecated and will be removed in a future release. Users of SSH tunnel functionality in Google Container Engine for the Master -> Cluster communication should plan alternate methods for bridging master and node networks. ([#54433](https://github.com/kubernetes/kubernetes/pull/54433),[ @dims](https://github.com/dims))

- HA improvements:
  - `kubeadm join --experimental-control-plane` can now be used to join control plane instances to an existing cluster.
  - `kubeadm upgrade node experimental-control-plane` can now be used for upgrading secondary control plane instances created with `kubeadm join --experimental-control-plane`.
Multi-arch support (EXPERIMENTAL):

release.  A new alpha feature is introduced to improve the mechanism that nodes heartbeat back to the control plane.  The `NodeLease` feature results in the node using a `Lease` resource in the `kube-node-lease` namespace that is renewed periodically.  The `NodeStatus` that was used previously to heartbeat back to the control plane is only updated when it changes.  This reduces load on the control plane for large clusters. The Kubelet plugin registration mechanism, which enables automatic discovery of external...

  - Please adapt your tooling built on top of kubeadm to use the "node-role.kubernetes.io/control-plane" label.
  - The taint applied to control-plane nodes "node-role.kubernetes.io/master:NoSchedule" is now deprecated and will be removed in a future release after a GA deprecation period.

* Action required: If you have a running federation control plane, you will have to ensure that for all federation resources, the corresponding namespace exists in federation control plane. ([#31139](https://github.com/kubernetes/kubernetes/pull/31139), [@nikhiljindal](https://github.com/nikhiljindal))

- kubeadm: removed the deprecated flag `--experimental-output`, please use the flag `--output` instead that serves the same purpose. Affected commands are: `kubeadm config images list`, `kubeadm token list`, `kubeadm upgrade plan`, `kubeadm certs check-expiration`. ([#126914](https://github.com/kubernetes/kubernetes/pull/126914), [@carlory](https://github.com/carlory)) [SIG Cluster Lifecycle]

ControlPlaneKubeletLocalMode feature gate. It can be used to tell kubeadm to use the local kube-apiserver endpoint for the kubelet when creating a cluster with "kubeadm init" or when joining control plane nodes with "kubeadm join".  The "kubeadm join" workflow now includes two new experimental phases called "control-plane-join-etcd" and "kubelet-wait-bootstrap" which will be used when the feature gate is enabled. This phases will be marked as non-experimental when ControlPlaneKubeletLocalMode becomes GA. During...