- The fallback behavior of the Downward API's `resourceFieldRef` field was updated to account for pod-level resources: if container-level limits were not set, pod-level limits were now used before falling back to node allocatable resources. ([#132605](https://github.com/kubernetes/kubernetes/pull/132605), [@toVersus](https://github.com/toVersus)) [SIG Node, Scheduling and Testing]

  - When registering with a 1.17+ API server, a CustomResourceDefinition conversion webhook can now request that only `v1` ConversionReview requests be sent to them. Previously, conversion webhooks were required to support receiving `v1beta1` ConversionReview requests as well for compatibility...

- Fix a bug where events/v1 Events with similar event type and reporting instance were not aggregated by client-go. ([#112365](https://github.com/kubernetes/kubernetes/pull/112365), [@dgrisonnet](https://github.com/dgrisonnet)) [SIG API Machinery and Instrumentation]

* The following deprecated flags were removed from `kube-controller-manager`:

  * `replication-controller-lookup-cache-size`
  * `replicaset-lookup-cache-size`
  * `daemonset-lookup-cache-size`

  Don't use these flags. Using deprecated flags causes the server to print a warning. Using a removed flag causes the server to abort the startup.

* The following deprecated flags were removed from `kubelet`:

- Kubeadm: Fixed a bug where the PublicKeysECDSA feature gate was not respected when generating kubeconfig files. ([#12538...

   ([#123273](https://github.com/kubernetes/kubernetes/pull/123273),...

  managed by the GLBC Ingress Controller. This can cause the health checks to start failing,
  requiring you to reapply the manual edits.
  * This issue does not affect clusters that were already running Kubernetes v1.6.4 or higher.
  * This issue does not affect Health Checks that were left in the configuration
    [originally set by the GLBC Ingress Controller](https://github.com/kubernetes/ingress-nginx/tree/0.9.0-beta.1/controllers/gce#health-checks).

- Fix static pod restarts in cases where the container is not present. ([#108189](https://github.com/kubernetes/kubernetes/pull/108189), [@rphillips](https://github.com/rphillips)) [SIG Node]

- Fixed a suboptimal scheduler preemption behavior where potential preemption victims were violating Pod Disruption Budgets. ([#128307](https://github.com/kubernetes/kubernetes/pull/128307), [@NoicFank](https://github.com/NoicFank)) [SIG Scheduling]
- Fixed an issue in the kubelet that showed when writeable layers and read-only layers were at different paths within the same mount.

SIG Node iterated on the ability to support more workloads with better performance and improved reliability.  Alpha features were improved around hardware accelerator support, device plugins enablement, and cpu pinning policies to enable us to graduate these features to beta in a future release.  In addition, a number of reliability and performance enhancements were made across the node to help operators in production.

### OpenStack