### CSI Service Account Token

CSI Service Account Token feature moves to Beta in 1.21. This feature improves the security posture and allows CSI drivers to receive pods' [bound service account tokens](https://github.com/kubernetes/enhancements/blob/master/keps/sig-auth/1205-bound-service-account-tokens/README.md). This feature also provides a knob to re-publish volumes so that short-lived volumes can be refreshed.

### CSI Health Monitoring

- Scheduler volumebinding: leveraged `PreFilterResult` to reduce down to only
  eligible node(s) for pod with bound claim(s) to local `PersistentVolume(s)` ([#109877](https://github.com/kubernetes/kubernetes/pull/109877), [@yibozhuang](https://github.com/yibozhuang))
- Scheduling cycle now terminates immediately when any scheduler plugin returns an 

* Addon manager supports HA masters. ([#55782](https://github.com/kubernetes/kubernetes/pull/55782), [@x13n](https://github.com/x13n))

- Disable aufs module for gce clusters. ([#103831](https://github.com/kubernetes/kubernetes/pull/103831), [@lizhuqi](https://github.com/lizhuqi))
- Do not unmount and mount subpath bind mounts during container creation unless bind mount changes ([#105512](https://github.com/kubernetes/kubernetes/pull/105512), [@gnufied](https://github.com/gnufied)) [SIG Storage]

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-apiserver: the insecure address flags `--address`, `--insecure-bind-address`, `--port` and `--insecure-port` (inert since 1.20) are removed ([#106859](https://github.com/kubernetes/kubernetes/pull/106859), [@knight42](https://github.com/knight42))

 - `kubeadm`: a separate "super-admin.conf" file is now deployed. The User in `admin.conf` is now bound to a new RBAC Group `kubeadm:cluster-admins` that has `cluster-admin` `ClusterRole` access. The User in `super-admin.conf` is now bound to the `system:masters` built-in super-powers / break-glass Group that can bypass RBAC. Before this change, the default `admin.conf` was bound to `system:masters` Group, which was undesired. Executing `kubeadm init phase kubeconfig all` or just `kubeadm...

    - `apiserver_flowcontrol_lower_limit_seats`: Configured lower bound on number of execution seats available to each priority level
    - `apiserver_flowcontrol_upper_limit_seats`: Configured upper bound on number of execution seats available to each priority level