<h3 id="Underlying_types">Underlying types</h3>

<p>
Each type <code>T</code> has an <i>underlying type</i>: If <code>T</code>
is one of the predeclared boolean, numeric, or string types, or a type literal,
the corresponding underlying type is <code>T</code> itself.
Otherwise, <code>T</code>'s underlying type is the underlying type of the
type to which <code>T</code> refers in its declaration.

  // +optional
  repeated string accessModes = 2;

  // capacity represents the actual resources of the underlying volume.
  // +optional
  map<string, k8s.io.apimachinery.pkg.api.resource.Quantity> capacity = 3;

  // conditions is the current Condition of persistent volume claim. If underlying persistent volume is being
  // resized then the Condition will be set to 'ResizeStarted'.
  // +optional

- Fix memory leak in kube-apiserver when underlying time goes forth and back. ([#96266](https://github.com/kubernetes/kubernetes/pull/96266), [@chenyw1990](https://github.com/chenyw1990)) [SIG API Machinery]

* Add support for finalizers in federated configmaps (deletes configmaps from underlying clusters). ([#40464](https://github.com/kubernetes/kubernetes/pull/40464), [@csbell](https://github.com/csbell))

- Fixed a bug in the JSON frame reader that could cause it to retain a reference to the underlying array of the byte slice passed to read. ([#123620](https://github.com/kubernetes/kubernetes/pull/123620), [@benluddy](https://github.com/benluddy))

* [alpha] Volume resizing

  * You can now increase the size of a volume by calling the Kubernetes API.

  * For alpha, this feature increases only the size of the underlying volume. It does not support resizing the file system.

  * For alpha, volume resizing supports only Gluster volumes.

* [alpha] Provide capacity isolation and resource management for local ephemeral storage

resourceVersion from the watch cache by default, as in <1.27 (disabling the change in #115096 by default). This mitigates the impact of an etcd watch bug (https://github.com/etcd-io/etcd/pull/17555). If the 1.27 change in #115096 to serve these requests from underlying storage is still desired despite the impact on watch stability, it can be re-enabled with a `WatchFromStorageWithoutResourceVersion` feature gate. ([#124007](https://github.com/kubernetes/kubernetes/pull/124007), [@serathius](https://github.com/serathius))...

## Changelog since v1.19.0

## What's New (Major Themes)

### Dockershim deprecation

Docker as an underlying runtime is being deprecated. Docker-produced images will continue to work in your cluster with all runtimes, as they always have.

- kubeadm no longer dumps backtrace if it fails to remove the running containers on reset. ([#73951](https://github.com/kubernetes/kubernetes/pull/73951), [@rosti](https://github.com/rosti))
- kubeadm: fixed a bug in the underlying library for diff related to characters like '%' ([#73941](https://github.com/kubernetes/kubernetes/pull/73941), [@neolit123](https://github.com/neolit123))

- Fixed CSIDriver API object to allow missing fields. ([#69331](https://github.com/kubernetes/kubernetes/pull/69331), [@jsafrane](https://github.com/jsafrane))