- Updated `kube-openapi` to remove invalid defaults: OpenAPI spec no longer includes default of `{}` for certain fields where it did not make sense. ([#120757](https://github.com/kubernetes/kubernetes/pull/120757), [@alexzielenski](https://github.com/alexzielenski))

a single one that can proceed is chosen via a uniform pseudo-random selection.
Otherwise, if there is a default case, that case is chosen.
If there is no default case, the "select" statement blocks until
at least one of the communications can proceed.
</li>

<li>
Unless the selected case is the default case, the respective communication
operation is executed.
</li>

<li>

  - `failurePolicy` default changed from `Ignore` to `Fail` for v1
  - `matchPolicy` default changed from `Exact` to `Equivalent` for v1
  - `timeout` default changed from `30s` to `10s` for v1
  - `sideEffects` default value is removed, and the field made required, and only `None` and `NoneOnDryRun` are permitted for v1

- Kubeadm: avoided uploading a defaulted flag value "--authorization-mode=Node,RBAC" for the kube-apiserver in the ClusterConfiguration stored in the "kube-system/kubeadm-config" ConfigMap. "Node,RBAC" are already the kubeadm defaults for this flag, so this action is redundant. ([#123555](https://github.com/kubernetes/kubernetes/pull/123555), [@neolit123](https://github.com/neolit123))...

([#58171](https://github.com/kubernetes/kubernetes/pull/58171), [@verult](https://github.com/verult))

* 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/ku...

### Volumes
* StorageClass pre-installed and set as default on Azure, AWS, GCE, OpenStack, and vSphere.
  * This is something to pay close attention to if you’ve been using Kubernetes for a while, because it changes the default behavior of PersistentVolumeClaim objects on these clouds.

- Graduated ServerSideFieldValidation to `beta`. Schema validation is performed server-side and requests will receive warnings for any invalid/unknown fields by default. ([#110178](https://github.com/kubernetes/kubernetes/pull/110178),...

#### CustomResourceDefinition Defaulting

CustomResourceDefinitions also have new support for defaulting, with defaults specified using the `default` keyword in the OpenAPI validation schema. Defaults are set for unspecified fields in an object sent to the API, and when reading from etcd.

Defaulting will be available as alpha in Kubernetes 1.15 and requires structural schemas.

  * Special notice for kube-proxy in 1.7+ (including 1.7.0):
    * Healthz server (/healthz) will be served on 0.0.0.0:10256 by default.
    * Metrics server (/metrics and /proxyMode) will be served on 127.0.0.1:10249 by default.
    * Metrics server will continue serving /healthz.


# v1.7.2

- Introduced the `admissionregistration.k8s.io/v1beta1/MutatingAdmissionPolicy` API type. To enable, enable the `MutatingAdmissionPolicy` feature gate (which was off by default) and set `--runtime-config=admissionregistration.k8s.io/v1beta1=true` on the kube-apiserver.