- Kubelet: Fix repeatedly acquiring the inhibit lock ([#98088](https://github.com/kubernetes/kubernetes/pull/98088), [@wzshiming](https://github.com/wzshiming)) [SIG Node]
- Kubelet: Fixed the bug of getting the number of cpu when the number of cpu logical processors is more than 64 in windows ([#97378](https://github.com/kubernetes/kubernetes/pull/97378), [@hwdef](https://github.com/hwdef)) [SIG Node and Windows]

- Fixed the issue where pod with ordinal number lower than the rolling partitioning number was being deleted it was coming up with updated image. ([#120731](https://github.com/kubernetes/kubernetes/pull/120731), [@adilGhaffarDev](https://github.com/adilGhaffarDev)) [SIG Apps and Testing]

  to its pre-1.27 behavior of tracking the total number of iptables rules that
  kube-proxy is responsible for, rather than only counting the number of rules
  that it re-synced on the last sync. The new `sync_proxy_rules_iptables_last`
  metric now gives the latter number. ([#119140](https://github.com/kubernetes/kubernetes/pull/119140), [@danwinship](https://github.com/danwinship)) [SIG Network]

* adjusted http/2 buffer sizes for apiservers to prevent starvation issues between concurrent streams ([#67902](https://github.com/kubernetes/kubernetes/pull/67902), [@liggitt](https://github.com/liggitt))
* Bump up version number of debian-base, debian-hyperkube-base and debian-iptables.  ([#67026](https://github.com/kubernetes/kubernetes/pull/67026), [@satyasm](https://github.com/satyasm))
    * Also updates dependencies of users of debian-base.

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 we can better monitor the...

* Add apiserver metric for number of requests dropped because of inflight limit. ([#58340](https://github.com/kubernetes/kubernetes/pull/58340), [@gmarek](https://github.com/gmarek))

### Bug or Regression

- Fixed a bug where a high churn of events was causing master instability by reducing the maximum number of objects (events) attached to a single etcd lease. ([#100452](https://github.com/kubernetes/kubernetes/pull/100452), [@mborsz](https://github.com/mborsz)) [SIG API Machinery and Instrumentation]

## Changelog since v1.13.6

### Other notable changes

* IPVS: Disable graceful termination for UDP traffic to solve issues with high number of UDP connections (DNS / syslog in particular) ([#77802](https://github.com/kubernetes/kubernetes/pull/77802), [@lbernail](https://github.com/lbernail))

- The `apiserver` exposes 4 new metrics that allow to track the status of the Service CIDRs allocations:
      - current number of available IPs per Service CIDR
      - current number of used IPs per Service CIDR
      - total number of allocation per Service CIDR
      - total number of allocation errors per ServiceCIDR ([#104119](https://github.com/kubernetes/kubernetes/pull/104119), [@aojea](https://github.com/aojea))

  - Clone `kubernetes/kubernetes` in `update-vendor.sh` shallowly, instead of fetching all revisions
  - Speed up binpacking by reducing the number of PreFilter calls (call once per pod instead of #pods*#nodes times)
  - Speed up finding unneeded nodes by 5x+ in very large clusters by reducing the number of PreFilter calls
  - Expose `--max-nodes-total` as a metric
  - Errors in `IncreaseSize` changed from type `apiError` to `cloudProviderError`