* kubeadm: Fix a bug on some OSes where the kubelet tried to mount a volume path that is non-existent and on a read-only filesystem  ([#55320](https://github.com/kubernetes/kubernetes/pull/55320), [@andrewrynhard](https://github.com/andrewrynhard))

- Fixed bug that caused a resource to include patch directives when using strategic merge patch against a non-existent field. ([#117568](https://github.com/kubernetes/kubernetes/pull/117568), [@alexzielenski](https://github.com/alexzielenski))

- `kubectl rollout undo` now returns errors when attempting to rollback a deployment to a non-existent revision ([#70039](https://github.com/kubernetes/kubernetes/pull/70039), [@liggitt](https://github.com/liggitt))

* Azure disks now support external resource groups.
([#64427](https://github.com/kubernetes/kubernetes/pull/64427), [@andyzhangx](https://github.com/andyzhangx))
* Added reason message logs for non-existent Azure resources.
([#64248](https://github.com/kubernetes/kubernetes/pull/64248), [@feiskyer](https://github.com/feiskyer))

### SIG CLI

## Changelog since v1.19.15

## Changes by Kind

### Bug or Regression

- Fix detach from non-existant nodes and support dangling volumes (#104912, @gnufied) [SIG Cloud Provider and Storage]
- Revert PR #102925 which introduced unexpected scheduling behavior based on balanced resource allocation (#105526, @harisund) [SIG Scheduling]

- Fixed static pod add and removes restarts in certain cases. ([#107695](https://github.com/kubernetes/kubernetes/pull/107695), [@rphillips](https://github.com/rphillips))
- Fixed: deleted a non-existent Azure disk issue. ([#107406](https://github.com/kubernetes/kubernetes/pull/107406), [@andyzhangx](https://github.com/andyzhangx))

* client-go: fake clients now properly return NotFound errors when attempting to patch non-existent objects ([#70886](https://github.com/kubernetes/kubernetes/pull/70886), [@bouk](https://github.com/bouk))