- Kubeadm: when using a custom image repository for CoreDNS kubeadm now will append the "coredns"  image name instead of  "coredns/coredns", thus restoring the behaviour existing before the v1.21 release. Users who rely on nested folder for the coredns image should set the "clusterConfiguration.dns.imageRepository" value including the nested path name (e.g using "registry.company.xyz/coredns" will force kubeadm to use "registry.company.xyz/coredns/coredns" image)....

* Default values differ between the Kubelet's componentconfig (config file) API and the Kubelet's command line. Be sure to review the default values when migrating to using a config file. For example, the authz mode is set to "AlwaysAllow" if you rely on the command line, but defaults to the more secure "Webhook" mode if you load config from a file. ([#59666](https://github.com/kubernetes/kubernetes/pull/59666), [@mtaufen](https://github.com/mtaufen))

http/2 requests from multiple clients share the same backend connection. An API server on a private network may choose not to enable the kube-apiserver mitigation to prevent performance regressions for unauthenticated clients. Authenticated requests rely on the fix in golang.org/x/net v0.17.0 alone. https://issue.k8s.io/121197 tracks further mitigation of http/2 attacks by authenticated clients. ([#121199](https://github.com/kubernetes/kubernetes/pull/121199), [@enj](https://github.com/enj)) [SIG API...

* Default mount propagation has changed from `HostToContainer` ("rslave" in Linux terminology), as it was in 1.10, to `None` ("private") to match the behavior...

- To address the possibility of dry-run requests overwhelming admission webhooks that rely on side effects and a reconciliation mechanism, a new field is being added to `admissionregistration.k8s.io/v1beta1.ValidatingWebhookConfiguration` and `admissionregistration.k8s.io/v1beta1.MutatingWebhookConfiguration` so that webhooks can explicitly...

by this vulnerability if you run a Validating Admission Webhook for Nodes
that denies admission based at least partially on the old state of the
Node object.

**Note**: This only impacts validating admission plugins that rely on old
values in certain fields, and does not impact calls from kubelets that go
through the built-in NodeRestriction admission plugin.

**Affected Versions**:
  - kube-apiserver v1.20.0 - v1.20.5

- Kubeadm no longer removes /etc/cni/net.d as it does not install it. Users should remove files from it manually or rely on the component that created them ([#83950](https://github.com/kubernetes/kubernetes/pull/83950), [@yastij](https://github.com/yastij))

6))

* [Action required] The validation rule for metadata.initializers.pending[x].name is tightened. The initializer name must contain at least three segments, separated by dots. You can create objects with pending initializers and not rely on the API server to add pending initializers according to `initializerConfiguration`. If you do so, update the initializer name in the existing objects and the configuration files to comply with the new validation rule.([#51283](https://github.co...

http/2 requests from multiple clients share the same backend connection. An API server on a private network may choose not to enable the kube-apiserver mitigation to prevent performance regressions for unauthenticated clients. Authenticated requests rely on the fix in golang.org/x/net v0.17.0 alone. https://issue.k8s.io/121197 tracks further mitigation of http/2 attacks by authenticated clients. ([#121196](https://github.com/kubernetes/kubernetes/pull/121196), [@enj](https://github.com/enj)) [SIG API...

If CSI Migration is working properly, Kubernetes end users shouldn’t notice a difference.
After migration, Kubernetes users may continue to rely on all the functionality of in-tree storage plugins using the existing interface.
- CSI Migration feature is turned on by default but stays in Beta for GCE PD, AWS EBS, and Azure Disk in 1.23.