CustomResourceDefinition](https://kubernetes.io/docs/tasks/access-kubernetes-api/migrate-third-party-resource/).

* [beta] User-provided apiservers can be aggregated (served along with) the rest of the Kubernetes API. See [Extending the Kubernetes API with the aggregation layer](https://kubernetes.io/docs/concepts/api-extension/apiserver-aggregation/), [Configure the aggregation layer](https://kubernetes.io/docs/tasks/access-kubernetes-api/configure-aggregation-layer/), and [Setup an...

* Allow the system:heapster ClusterRole read access to deployments ([#48357](https://github.com/kubernetes/kubernetes/pull/48357), [@faraazkhan](https://github.com/faraazkhan))
* Ensure get_password is accessing a file that exists. ([#48351](https://github.com/kubernetes/kubernetes/pull/48351), [@ktsakalozos](https://github.com/ktsakalozos))

    *   Pod Security Policy can now manage access to specific FlexVolume drivers.([#53179](https://github.com/kubernetes/kubernetes/pull/53179),[ @wanghaoran1988](https://github.com/wanghaoran1988))
    *   To prevent unauthorized access to CHAP Secrets, you can now set the secretNamespace storage class parameters for the following volume types:

  - [Changelog since v1.21.4](#changelog-since-v1214)
  - [Important Security Information](#important-security-information)
    - [CVE-2021-25741: Symlink Exchange Can Allow Host Filesystem Access](#cve-2021-25741-symlink-exchange-can-allow-host-filesystem-access)
  - [Changes by Kind](#changes-by-kind-8)
    - [Feature](#feature-6)
    - [Bug or Regression](#bug-or-regression-8)
    - [Other (Cleanup or Flake)](#other-cleanup-or-flake-1)

* The kubelet API is now secured, only cluster admins are allowed to access it.
* Insecure access to the API Server over `localhost:8080` is now disabled.
* The control plane components now talk securely to each other. The API Server talks securely to the kubelets in the cluster.

* [advanced audit] support subresources wildcard matching. ([#55306](https://github.com/kubernetes/kubernetes/pull/55306), [@hzxuzhonghu](https://github.com/hzxuzhonghu))
* CronJobs can be accessed through cj alias ([#59499](https://github.com/kubernetes/kubernetes/pull/59499), [@soltysh](https://github.com/soltysh))

		{
			authString:    fmt.Sprintf("%s %s", signV2Algorithm, accessID),
			expectedError: ErrMissingFields,
		},
		// Test case - 5.
		// Test case with wrong accessID.
		{
			authString:    fmt.Sprintf("%s %s:%s", signV2Algorithm, "InvalidAccessID", "signature"),
			expectedError: ErrInvalidAccessKeyID,
		},
		// Test case - 6.
		// Case with right accessID and format.
		{

			objectName:         "abcd",
			accessKey:          credentials.AccessKey,
			secretKey:          credentials.SecretKey,
			expectedRespStatus: http.StatusNotFound,
		},
		// Test case - 3.
		// Test case to induce a signature mismatch.
		// Using invalid accessID.
		{
			bucketName:         bucketName,
			objectName:         objectName,
			accessKey:          "Invalid-AccessID",

		bucket             string
		objects            []byte
		accessKey          string
		secretKey          string
		expectedContent    []byte
		expectedRespStatus int
	}{
		// Test case - 0.
		// Delete objects with invalid access key.
		0: {
			bucket:             bucketName,
			objects:            successRequest0,
			accessKey:          "Invalid-AccessID",
			secretKey:          credentials.SecretKey,

	if len(accessKey) < accessKeyMinLen || len(accessKey) > accessKeyMaxLen {
		return Credentials{}, ErrInvalidAccessKeyLength
	}

	if len(secretKey) < secretKeyMinLen || len(secretKey) > secretKeyMaxLen {
		return Credentials{}, ErrInvalidSecretKeyLength
	}

	cred.AccessKey = accessKey
	cred.SecretKey = secretKey