([#123413](https://github.com/kubernetes/kubernetes/pull/123413), [@seans3](https://github.com/seans3))
- A new flag called `custom` has been introduced in `kubectl debug`, allowing users to customize pre-defined profiles. ([#120346](https://github.com/kubernetes/kubernetes/pull/120346), [@ardaguclu](https://github.com/ardaguclu))

kubernetes/kubeadm: [#1204](https://github.com/kubernetes/kubeadm/issues/1204)

- Introduce CSI Cluster Registration mechanism to ease CSI plugin discovery and allow CSI drivers to customize Kubernetes' interaction with them. ([#67803](https://github.com/kubernetes/kubernetes/pull/67803), [@saad-ali](https://github.com/saad-ali))

*   [beta] Flag `--chunk-size={SIZE}` is added to `kubectl get` to customize the number of results returned in large lists of resources. This reduces the perceived latency of managing large clusters because the server returns the first set of results to the client much more quickly. Pass 0 to disable this feature.([#5376...

- Support custom tags for cloud provider managed resources ([#96450](https://github.com/kubernetes/kubernetes/pull/96450), [@nilo19](https://github.com/nilo19)) [SIG Cloud Provider]
- Support customize load balancer health probe protocol and request path ([#96338](https://github.com/kubernetes/kubernetes/pull/96338), [@nilo19](https://github.com/nilo19)) [SIG Cloud Provider]

* [stable] The PV spec for Azure File, CephFS, iSCSI, and Glusterfs is modified to reference namespaced resources.

* [stable] You can now customize the iSCSI initiator name per volume in the iSCSI volume plugin.

* [stable] You can now specify the World Wide Identifier (WWID) for the volume identifier in the Fibre Channel volume plugin.

- 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:

    * PR [#278](https://github.com/tiangolo/fastapi/pull/278).

## 0.26.0

* Separate error handling for validation errors.
    * This will allow developers to customize the exception handlers.
    * Document better how to handle exceptions and use error handlers.