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))...

wondered at this, but at the time it all seemed quite natural);
but when the Rabbit actually TOOK A WATCH OUT OF ITS WAISTCOAT-
POCKET, and looked at it, and then hurried on, Alice started to
her feet, for it flashed across her mind that she had never
before seen a rabbit with either a waistcoat-pocket, or a watch to
take out of it, and burning with curiosity, she ran across the

  Once core Kubernetes support for user namespaces is generally available and kubeadm has started to support running the control plane in userns pods, the kubeadm `RootlessControlPlane` feature gate will be removed entirely.

* Allow access to ClusterIP from the host network namespace when kube-proxy is started in IPVS mode without either masqueradeAll or clusterCIDR flags ([#65388](https://github.com/kubernetes/kubernetes/pull/65388), [@lbernail](https://github.com/lbernail))

                    required:
                    - port
                    type: object
                  initialDelaySeconds:
                    description: Number of seconds after the container has started
                      before readiness probes are initiated.
                    format: int32
                    minimum: 0
                    type: integer
                  periodSeconds:

* 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))

- 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]

- 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]

- Added a new scheduler metric, `pod_scheduling_sli_duration_seconds`, and started the deprecation for `pod_scheduling_duration_seconds`. ([#119049](https://github.com/kubernetes/kubernetes/pull/119049), [@helayoty](https://github.com/helayoty))