use to accurately and efficiently track set membership across `apply` operations. The format used for `ApplySet` is set out in  [KEP 3659](https://github.com/kubernetes/enhancements/issues/3659) as a low-level specification.  Other tools in the ecosystem can also build on this specification for improved interoperability.  To try the ApplySet-based pruning alpha, set `KUBECTL_APPLYSET=true` and use the flags `--prune --applyset=secret-name` with `kubectl apply`. ([#116205](https://github.com/kuber...

m/ijc))

* kubeadm: New "imagePullPolicy" option in the init configuration file, that gets forwarded to kubelet static pods to control pull policy for etcd and control plane images. This option allows for precise image pull policy specification for master nodes and thus for more tight control over images. It is useful in CI environments and in environments, where the user has total control over master VM templates (thus, the master VM templates can be preloaded with the required Docker...

In addition, users can now create multiple versions of CustomResourceDefinitions, but without any kind of automatic conversion, and CustomResourceDefinitions now allow specification of additional columns for `kubectl get` output via the `spec.additionalPrinterColumns` field.

### SIG Auth

1) Alpha for AWS ALB (Application Load Balancer) integration to Kubernetes Ingress resources.
2) Alpha for CSI specification 0.3 integration to AWS EBS (Elastic Block Store)

- In a future release, kubelet will no longer create the CSI NodePublishVolume target directory, in accordance with the CSI specification. CSI drivers may need to be updated accordingly to properly create and process the target path. ([#75535](https://github.com/kubernetes/kubernetes/issues/75535)) [SIG Storage]

#### kube-proxy:

- Removed the networking `alpha` API `ClusterCIDR`. ([#121229](https://github.com/kubernetes/kubernetes/pull/121229),...

    *  - Created new GCE_SSH_KEY allowing specification of SSH keys for gce, gke, and kubemark.
    *  - AWS_SSH_KEY, previously assumed to be an absolute path can now be either relative or absolute

* Alpha support for OpenAPI (aka. Swagger 2.0) specification served on /swagger.json (enabled by default)  ([#30233](https://github.com/kubernetes/kubernetes/pull/30233), [@mbohlool](https://github.com/mbohlool))

- **[alpha]** Represent node problems "not ready" and "unreachable" using `NoExecute` taints. In combination with `tolerationSeconds` described below, this allows per-pod specification of how long to remain bound to a node that becomes unreachable or not ready, rather than using the default of 5 minutes. You can enable this alpha feature by including `TaintBasedEvictions=true` in `--feature-gates`, such as `--feature-gates=F...

* Add perma-failed deployments API ([#19343](https://github.com/kubernetes/kubernetes/pull/19343), [@kargakis](https://github.com/kargakis))

### Other notable changes

* Federation: allow specification of dns zone by ID ([#36336](https://github.com/kubernetes/kubernetes/pull/36336), [@justinsb](https://github.com/justinsb))