PodDisruptionBudget handling of "strategic merge patch"-type API requests for the `selector` field. Prior to 1.21, these requests would merge `matchLabels` content and replace `matchExpressions` content. In 1.21, patch requests touching the `selector` field started replacing the entire selector. This is consistent with server-side apply and the v1 PodDisruptionBudget behavior, but should not have been changed for v1beta1. ([#108142](https://github.com/kubernetes/kubernetes/pull/108142), [@liggitt](https://github.com/liggitt))...

- Performance improvements in `klog` ([#115277](https://github.com/kubernetes/kubernetes/pull/115277), [@pohly](https://github.com/pohly))
- Pod template `schedulingGates` are now mutable for Jobs that are suspended and have never been started ([#115940](https://github.com/kubernetes/kubernetes/pull/115940), [@ahg-g](https://github.com/ahg-g)) [SIG Apps]

* rkt version 1.23.0+

    * known issues with the rkt runtime are [listed in the Getting Started Guide](https://kubernetes.io/docs/getting-started-guides/rkt/notes/)

* etcd version 3.0.17

* Go version: 1.8.3. [Link to announcement](https://groups.google.com/d/msg/kubernetes-dev/0XRRz6UhhTM/YODWVnuDBQAJ)

* Ensure cloudprovider.InstanceNotFound is reported when the VM is not found on Azure ([#61531](https://github.com/kubernetes/kubernetes/pull/61531), [@feiskyer](https://github.com/feiskyer))
* On AWS kubelet returns an error when started under conditions that do not allow it to work (AWS has not yet tagged the instance). ([#60125](https://github.com/kubernetes/kubernetes/pull/60125), [@vainu-arto](https://github.com/vainu-arto))

INFO:     Will watch for changes in these directories: ['/home/user/code/awesomeapp']
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [2248755] using WatchFiles
INFO:     Started server process [2248757]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
```

### Refactors

...

- Pods that are considered for preemption and haven't started don't produce an error log. ([#87900](https://github.com/kubernetes/kubernetes/pull/87900), [@alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]

* On AWS kubelet returns an error when started under conditions that do not allow it to work (AWS has not yet tagged the instance). ([#60125](https://github.com/kubernetes/kubernetes/pull/60125), [@vainu-arto](https://github.com/vainu-arto))

	// The mode defines the action the controller will take when a pod is detected as broken.
	// If repairPods is true, the controller will dynamically repair any broken pod by setting up the pod networking configuration even after it has started.
	// Note the pod will be crashlooping, so this may take a few minutes to become fully functional based on when the retry occurs.
	// This requires no RBAC privilege, but will require the CNI agent to run as a privileged pod.

- Pause image contains "Architecture" in non-amd64 images ([#87954](https://github.com/kubernetes/kubernetes/pull/87954), [@BenTheElder](https://github.com/BenTheElder)) [SIG Release]
- Pods that are considered for preemption and haven't started don't produce an error log. ([#87900](https://github.com/kubernetes/kubernetes/pull/87900), [@alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]