- The `SidecarContainers` feature has graduated to `beta` and is enabled by default. ([#121579](https://github.com/kubernetes/kubernetes/pull/121579), [@gjkim42](https://github.com/gjkim42))
- The `kube-apiserver` will now expose four new metrics to inform about errors on the clusterIP and nodePort allocation logic. ([#120843](https://github.com/kubernetes/kubernetes/pull/120843), [@aojea](https://github.com/aojea))

* Performance test framework and basic tests for the IPAM controller, to simulate behavior of the four supported modes under lightly loaded and loaded conditions, where load is defined as the number of operations to perform as against the configured kubernetes. ([#61143](https://github.com/kubernetes/kubernetes/pull/61143), [@satyasm](https://github.com/satyasm))...

used space on volumes created using vSphere. ([#59328](https://github.com/kubernetes/kubernetes/pull/59328), [@divyenpatel](https://github.com/divyenpatel))

* Emit number of bound and unbound persistent volumes as Metrics. This PR adds four kinds of Volume Metrics for kube-controller-manager: bound PVC numbers, unbound PVC numbers, bound PV numbers and unbound PV numbers. The PVC metrics use namespace as dimension and the PV metrics use StorageClassName as its dimension. With these metrics...