* Added exported env vars to kubectl plugins so that plugin developers have access to global flags, namespace, the plugin descriptor and the full path to the caller binary.

  * Enhancement

 - Scheduler's CycleState now embeds internal read/write locking inside its `Read()` and `Write()` functions. Meanwhile, `Lock()` and `Unlock()` function are removed. Scheduler plugin developers are now required to remove `CycleState#Lock()` and `CycleState#Unlock()`. Just simply use `Read()` and `Write()` as they're natively thread-safe now. ([#101542](https://github.com/kubernetes/kubernetes/pull/101542), [@Huang-Wei](https://github.com/Huang-Wei))...

containers](https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/), it became more obvious how we can support developers with tooling built on top of `kubectl exec`. The addition of the `kubectl debug` [command](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/1441-kubectl-debug/README.md) (it is alpha but your feedback is more than welcome), allows developers to easily debug their Pods inside the cluster. We think this addition is invaluable.  This command allows one to create...

## Changelog since v1.27.0

## Urgent Upgrade Notes 

### (No, really, you MUST read this before you upgrade)

- Action required for the custom scheduler plugin developers. 
  Here's the breaking change in `EnqueueExtension` in the scheduling framework. 

- For scheduler plugin developers: the scheduler framework's shared PodInformer is now initialized with empty indexers. This enables scheduler plugins to add their extra indexers. Note that only non-conflict indexers are allowed to be added. ([#110663](https://github.com/kubern...

content type of `text/plain` containing JSON data would be accepted and the JSON data would be extracted.

But requests with content type `text/plain` are exempt from [CORS](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS) preflights, for being considered [Simple requests](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#simple_requests). So, the browser would execute them right away including cookies, and the text content could be a JSON string that would be parsed and accepted...

    * Added exported env vars to kubectl plugins so that plugin developers have access to global flags, namespace, the plugin descriptor and the full path to the caller binary.

With CSI the Kubernetes volume layer becomes truly extensible, allowing third party storage developers to write drivers making their storage systems available in Kubernetes without having to touch the core code.

CSI was first introduction as alpha in Kubernetes v1.9 and moved to beta in Kubernetes v1.10.

Pruning is activated by setting `spec.preserveUnknownFields: false` in the CustomResourceDefinition. A future apiextensions.k8s.io/v1 variant of CRDs will enforce pruning.

  // +optional
  optional AWSElasticBlockStoreVolumeSource awsElasticBlockStore = 2;

  // hostPath represents a directory on the host.
  // Provisioned by a developer or tester.
  // This is useful for single-node development and testing only!
  // On-host storage is not supported in any way and WILL NOT WORK in a multi-node cluster.