### Promoted Local Ephemeral Storage Capacity Isolation to Stable

Pod with multiple containers can use `kubectl.kubernetes.io/default-container` annotation to have a container preselected for kubectl commands. More can be read in [KEP-2227](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/2227-kubectl-default-container/README.md).

### Immutable Secrets and ConfigMaps

- Deprecate `--record` flag in `kubectl`. The `--record` flag is being replaced with the [mechanism](https://github.com/kubernetes/enhancements/tree/master/keps/sig-cli/859-kubectl-headers) which annotates HTTP requests with kubectl command details. ([#102873](https://github.com/kubernetes/kubernetes/pull/102873), [@soltysh](https://github.com/soltysh))

- Added Custom resource field selectors in beta and enabled them by default. Check out https://github.com/kubernetes/enhancements/issues/4358 for more details. ([#124681](https://github.com/kubernetes/kubernetes/pull/124681), [@jpbetz](https://github.com/jpbetz)) [SIG API Machinery, Auth and Testing]

Topology constraints addressed the first point, but up to now pod scheduling was still done without considering that the remaining storage capacity may not be enough to start a new pod. [Storage capacity tracking](https://github.com/kubernetes/enhancements/tree/master/keps/sig-storage/1472-storage-capacity-tracking), a new alpha feature, addresses that by adding an API for a CSI driver to report storage capacity and uses that information in the Kubernetes scheduler when choosing a node for a pod....

with this, and the default behavior was changed. The `VolumeCapacityPriority` preferred a node with the least allocatable, but the `StorageCapacityScoring` preferred a node with the maximum allocatable. See [KEP-4049](https://github.com/kubernetes/enhancements/blob/master/keps/sig-storage/4049-storage-capacity-scoring-of-nodes-for-dynamic-provisioning/README.md) for details. ([#128184](https://github.com/kubernetes/kubernetes/pull/128184), [@cupnes](https://github.com/cupnes)) [SIG Scheduling, Storage...

We expect this implementation to progress from alpha to beta and GA in coming releases, so we’re eager to have you comment about your dual-stack experiences in [#k8s-dual-stack](https://kubernetes.slack.com/messages/k8s-dual-stack) or in [enhancements #563](https://features.k8s.io/563). 

### go1.15.5

- Changed kuberc configuration schema. Two new optional fields added to kuberc configuration, `credPluginPolicy` and `credPluginAllowlist`. This is documented in [KEP-3104](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/3104-introduce-kuberc/README.md#allowlist-design-details) and documentation is added to the website by [kubernetes/website#52877](https://github.com/kubernetes/website/pull/52877) ([#134870](https://github.com/kubernet...

proto messages. Protobuf serialization of Kubernetes API types should use [k8s.io/apimachinery/pkg/runtime/serializer/protobuf](https://pkg.go.dev/k8s.io/apimachinery/pkg/runtime/serializer/protobuf). See [KEP-5589](https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/5589-gogo-dependency) for more details. ([#137084](https://github.com/kubernetes/kubernetes/pull/137084), [@liggitt](https://github.com/liggitt)) [SIG API Machinery, Apps, Architecture, Auth, Node, Scheduling...

containers](https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/), it became more obvious how we can support developers with tooling built on top of `kubectl exec`. The addition of the `kubectl debug` [command](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/1441-kubectl-debug/README.md) (it is alpha but your feedback is more than welcome), allows developers to easily debug their Pods inside the cluster. We think this addition is invaluable.  This command allows one to create...