- `readOnly` volumes now support recursive read-only mounts for kernel versions >= 5.12."
   ([#123180](https://github.com/kubernetes/kubernetes/pull/123180), [@AkihiroSuda](https://github.com/AkihiroSuda))
- cri-api: Implemented KEP-3857: Recursive Read-only (RRO) mounts.

    - [IPv4/IPv6 run](#ipv4ipv6-run)
    - [go1.15.5](#go1155)
    - [CSI Volume Snapshot graduates to General Availability](#csi-volume-snapshot-graduates-to-general-availability)
    - [Non-recursive Volume Ownership (FSGroup) graduates to Beta](#non-recursive-volume-ownership-fsgroup-graduates-to-beta)
    - [CSIDriver policy for FSGroup graduates to Beta](#csidriver-policy-for-fsgroup-graduates-to-beta)

- Fixed null `lastTransitionTime` in Pod condition when setting the scheduling gate. ([#122636](https://github.com/kubernetes/kubernetes/pull/122636), [@lianghao208](https://github.com/lianghao208)) [SIG Node and Scheduling]
- Fixed recursive LIST from watch cache returning object matching key. ([#125584](https://github.com/kubernetes/kubernetes/pull/125584), [@serathius](https://github.com/serathius)) [SIG API Machinery and Testing]

SIG Storage is also introducing the following new storage features as alpha in Kubernetes 1.18:
- Windows CSI Support: Enabling containerized CSI node plugins in Windows via new [CSIProxy](https://github.com/kubernetes-csi/csi-proxy)
- Recursive Volume Ownership OnRootMismatch Option: Add a new “OnRootMismatch” policy that can help shorten the mount time for volumes that require ownership change and have many directories and files.

### Other notable announcements

- Deprecated the following kubectl run flags, which are ignored if set: `--cascade`, `--filename`, `--force`, `--grace-period`, `--kustomize`, `--recursive`, `--timeout`, `--wait`. ([#112261](https://github.com/kubernetes/kubernetes/pull/112261), [@brianpursley](https://github.com/brianpursley))

* ✨ Update OpenAPI models, supporting recursive models and extensions. PR [#3628](https://github.com/tiangolo/fastapi/pull/3628) by [@tiangolo](https://github.com/tiangolo).

for x := range fibo {
	if x >= 1000 {
		break
	}
	fmt.Printf("%d ", x)
}
// output: 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987

// iteration support for a recursive tree data structure
type Tree[K cmp.Ordered, V any] struct {
	left, right *Tree[K, V]
	key         K
	value       V
}

func (t *Tree[K, V]) walk(yield func(key K, val V) bool) bool {

### Skip Volume Ownership change graduates to GA

The feature to configure volume permission and ownership change policy for Pods moved to GA in 1.23.
This allows users to skip recursive permission changes on mount and speeds up the pod start up time.

### Allow CSI drivers to opt-in to volume ownership and permission change graduates to GA