* kube-proxy needs to be configured to override hostname in some environments. ([#857](https://github.com/kubernetes/kubeadm/issues/857), [@detiber](https://github.com/detiber))

- kube-controller-manager currently needs a writable `--cert-dir` (default is `/var/run/kubernetes`) for generating self-signed certificates, when no `--tls-cert-file` or `--tls-private-key-file` are provided.

#### Storage
- A node that uses a CSI raw block volume needs to be drained before kubelet can be upgraded to 1.17. ([#74026](https://github.com/kubernetes/kubernetes/pull/74026), [@mkimuram](https://github.com/mkimuram))

#### Windows

* Action required: validation rule on metadata.initializers.pending[x].name is tightened. The initializer name needs to contain at least three segments separated by dots. If you create objects with pending initializers, (i.e., not relying on apiserver adding pending initializers according to initializerconfiguration), you need to update the initializer name in existing...

    *    That means, now  VCP can handle cases where user changes VM inventory name.
    * - VCP can handle cases where VM migrates to other ESXi cluster or datacenter or vCenter.
    * The only requirement is the shared storage. VCP needs shared storage on all Node VMs.
* The RBAC bootstrapping policy now allows authenticated users to create selfsubjectrulesreviews. ([#56095](https://github.com/kubernetes/kubernetes/pull/56095), [@ericchiang](https://github.com/ericchiang))

- When using `kubectl replace` (or the equivalent API call) on a Service, the caller no longer needs to do a read-modify-write cycle to fetch the allocated values for `.spec.clusterIP` and `.spec.ports[].nodePort`.  Instead the API server will automatically carry these forward from the original object when the new object does not specify them. ([...

- When using `kubectl replace` (or the equivalent API call) on a Service, the caller no longer needs to do a read-modify-write cycle to fetch the allocated values for `.spec.clusterIP` and `.spec.ports[].nodePort`.  Instead the API server will automatically carry these forward from the original object when the new object does not specify them. ([...

* The deprecated kubelet --configure-cbr0 flag has been removed, and with that the "classic" networking mode as well.  If you depend on this mode, please investigate whether the other network plugins `kubenet` or `cni` meet your needs. ([#34906](https://github.com/kubernetes/kubernetes/pull/34906), [@luxas](https://github.com/luxas))

- kube-scheduler

  - Migrate scheduler to use v1beta1 Event API. any tool targeting scheduler events needs to use v1beta1 Event API ([#78447](https://github.com/kubernetes/kubernetes/pull/78447), [@yastij](https://github.com/yastij))

- kubeadm

  - The CoreDNS Deployment now checks readiness via the `ready` plugin.

- Track the number of Pods with a Ready condition in Job status. The feature is alpha and needs the feature gate JobReadyPods to be enabled. ([#104915](https://github.com/kubernetes/kubernetes/pull/104915), [@alculquicondor](https://github.com/alculquicondor))