- Kubeadm: fixed a regression where the JoinConfiguration.discovery.timeout was no longer respected and the value was always hardcoded to "5m" (5 minutes). ([#125481](https://github.com/kubernetes/kubernetes/pull/125481), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

- 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:

- `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))

* kube-apiserver now includes all registered API groups in discovery, including registered extension API group/versions for unavailable extension API servers. ([#66932](https://github.com/kubernetes/kubernetes/pull/66932), [@nilebox](https://github.com/nilebox))

* attachdetach controller attaches volumes immediately when Pod's PVCs are bound ([#66863](https://github.com/kubernetes/kubernetes/pull/66863), [@cofyc](https://github.com/cofyc))
* kube-apiserver now includes all registered API groups in discovery, including registered extension API group/versions for unavailable extension API servers. ([#66932](https://github.com/kubernetes/kubernetes/pull/66932), [@nilebox](https://github.com/nilebox))

- client-go discovery clients constructed using `NewDiscoveryClientForConfig` or `NewDiscoveryClientForConfigOrDie` default to rate limits that cause normal discovery request patterns to take several seconds. This is fixed in https://issue.k8s.io/86168 and will be resolved in v1.17.1. As a workaround, the `Burst` value can be adjusted higher...

- 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]

- Fix race in alpha aggregated discovery handler
  Yes, discovery document will correctly return the resources for aggregated apiservers that do not implement aggregated disovery ([#115805](https://github.com/kubernetes/kubernetes/pull/115805), [@alexzielenski](https://github.com/alexzielenski)) [SIG API Machinery]

  - 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".

- 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]