and enabled by default. When enabled, Secret API objects containing service account tokens are no longer auto-generated for every ServiceAccount. Use the [TokenRequest](https://kubernetes.io/docs/reference/kubernetes-api/authentication-resources/token-request-v1/) API to acquire service account tokens, or if a non-expiring token is required, create a Secret API object for the token controller to populate with a service account token by following this [guide](https://kubernetes.io/docs/concepts/conf...

Kubernetes where users may be able to launch containers that bypass the mountable secrets policy enforced by the ServiceAccount admission plugin when using ephemeral containers. The policy ensures pods running with a service account may only reference secrets specified in the service account's secrets field. Kubernetes clusters are only affected if the ServiceAccount admission plugin and the `kubernetes.io/enforce-mountable-secrets` annotation are used together with ephemeral containers.

**Note**:...

* The `kube-cloud-controller-manager` flag `--service-account-private-key-file` has been removed. Use `--use-service-account-credentials` instead. ([#60875](https://github.com/kubernetes/kubernetes/pull/60875), [@charrywanganthony](https://github.com/charrywanganthony))

## Changelog since v1.13.1

### Other notable changes

* client-go: shortens refresh period for token files to 1 minute to ensure auto-rotated projected service account tokens are read frequently enough. ([#72437](https://github.com/kubernetes/kubernetes/pull/72437), [@liggitt](https://github.com/liggitt))

- Exposed CSI volume stats via kubelet volume metrics ([#76188](https://github.com/kubernetes/kubernetes/pull/76188), [@humblec](https://github.com/humblec))
- Added a new `storage_operation_status_count` metric for kube-controller-manager and kubelet to count success and error statues. ([#75750](https://github.com/kubernetes/kubernetes/pull/75750), [@msau42](https://github.com/msau42))

### Deprecated/changed metrics

- The alpha feature `ServiceAccountIssuerDiscovery` enables publishing OIDC discovery information and service account token verification keys at `/.well-known/openid-configuration` and `/openid/v1/jwks` endpoints by API servers configured to issue service account tokens. ([#80724](https://github.com/kubernetes/kubernetes/pull/80724), [@cceckman](https://github.com/cceckman)) [SIG API Machinery, Auth, Cluster Lifecycle and Testing]

unprivileged pods, using the proxy to perform privileged storage operations on the node.

Another feature moving to GA in v1.22 is CSI Service Account Token support. This feature allows CSI drivers to use pods' [bound service account tokens](https://kubernetes.io/docs/reference/access-authn-authz/service-accounts-admin/#bound-service-account-token-volume) instead of a more privileged identity. It also provides control over to re-publishing these volumes, so that short-lived tokens can be refreshed....

- `kube-controller-manager`: The `LegacyServiceAccountTokenCleanUp` feature gate
  is now available as alpha (off by default). When enabled, the `legacy-service-account-token-cleaner`
  controller loop removes service account token secrets that have not been used
  in the time specified by `--legacy-service-account-token-clean-up-period` (defaulting
  to one year), **and are** referenced from the `.secrets` list of a ServiceAccount

- Some apiserver metrics were changed, as follows.
  - `priority_level_seat_count_samples` is replaced with `priority_level_seat_utilization`, which samples every nanosecond rather than every millisecond; the old metric conveyed utilization despite its name.
  - `priority_level_seat_count_watermarks` is removed.

        * `apiserver_request_count`
        * `apiserver_request_latencies`
        * `apiserver_request_latencies_summary`
        * `apiserver_dropped_requests`
        * `etcd_helper_cache_hit_count`
        * `etcd_helper_cache_miss_count`
        * `etcd_helper_cache_entry_count`
        * `etcd_request_cache_get_latencies_summary`