- Resolves a spurious "Unknown discovery response content-type" error in client-go discovery requests by tolerating extra content-type parameters in API responses ([#117571](https://github.com/kubernetes/kubernetes/pull/117571), [@seans3](https://github.com/seans3)) [SIG API Machinery]

- `discovery.k8s.io/v1beta1` EndpointSlices are deprecated in favor of `discovery.k8s.io/v1`, and will no longer be served in Kubernetes v1.25. ([#100472](https://github.com/kubernetes/kubernetes/pull/100472), [@liggitt](https://github.com/liggitt))

  - The "extraArgs" component construct is now a list of "name"/"value" pairs instead of a string/string map. This has been done to support duplicate args where needed.
  - The "JoinConfiguration.discovery.timeout" field has been replaced by "JoinConfiguration.timeouts.discovery".
  - The "ClusterConfiguration.timeoutForControlPlane" field has been replaced by "{Init|Join}Configuration.timeouts.controlPlaneComponentHealthCheck".

- Volume Cloning: Duplicate a PersistentVolumeClaim and underlying storage volume using the Kubernetes API via CSI.
- CSIDriver Kubernetes API Object: Simplifies CSI driver discovery and allows CSI Drivers to customize Kubernetes behavior.

SIG Storage is also introducing the following new storage features as alpha in Kubernetes 1.18:

Il est également possible que, pour une raison quelconque, vous ayez un **pic** d'utilisation de votre API. Peut‑être qu'elle devient virale, ou peut‑être que d'autres services ou bots commencent à l'utiliser. Et vous voudrez peut‑être disposer de ressources supplémentaires pour être en sécurité dans ces cas.

- Kubeadm: when using '--v=1' or higher log verbosity, print information of the CA certificate used for discovery  when using 'kubeadm join'. ([#137102](https://github.com/kubernetes/kubernetes/pull/137102), [@sivchari](https://github.com/sivchari)) [SIG Cluster Lifecycle]

folks who want the fairly language neutral ICU analyzer but the library to
implement the analyzer is 11MB so we don't ship it with Elasticsearch by
default.

Another example is the `discovery-gce` plugin. It is *vital* to folks running
in [GCP](https://cloud.google.com/) but useless otherwise and it depends on a
dozen extra jars.

#### `qa`

== Environment misc

There is a known issue with macOS localhost resolve strategy that can cause
some integration tests to fail. This is because integration tests have timings
for cluster formation, discovery, etc. that can be exceeded if name resolution
takes a long time.
To fix this, make sure you have your computer name (as returned by `hostname`)
inside `/etc/hosts`, e.g.:
....
127.0.0.1       localhost ElasticMBP.local

- Aggregated Discovery v2beta1 fixture is removed in `./api/discovery`. Please use v2 ([#127008](https://github.com/kubernetes/kubernetes/pull/127008), [@Jefftree](https://github.com/Jefftree)) [SIG API Machinery]

- Fixed a regression in the default `v1.27` configurations in `kube-apiserver`: fixed the `AggregatedDiscoveryEndpoint` feature (`beta` in `v1.27+`) to successfully fetch discovery information from aggregated API servers that do not check `Accept` headers when serving the `/apis` endpoint. ([#119870](https://github.com/kubernetes/kubernetes/pull/119870), [@Jefftree](https://github.com/Jefftree))