- Introduce a churn operator to scheduler perf testing framework. ([#98900](https://github.com/kubernetes/kubernetes/pull/98900), [@Huang-Wei](https://github.com/Huang-Wei)) [SIG Scheduling and Testing]

* Fixes issue where subpath readOnly mounts failed ([#63045](https://github.com/kubernetes/kubernetes/pull/63045), [@msau42](https://github.com/msau42))
* Add MAX_PODS_PER_NODE env so that GCE/GKE user can use it to specify the default max pods per node for the cluster. IP_ALIAS_SIZE will be changed accordingly. Must have ip alias enabled. ([#63621](https://github.com/kubernetes/kubernetes/pull/63621), [@grayluck](https://github.com/grayluck))

* Add MAX_PODS_PER_NODE env so that GCE/GKE user can use it to specify the default max pods per node for the cluster. IP_ALIAS_SIZE will be changed accordingly. Must have ip alias enabled. ([#63451](https://github.com/kubernetes/kubernetes/pull/63451), [@grayluck](https://github.com/grayluck))

## Changelog since v1.8.12

### Other notable changes

* Add MAX_PODS_PER_NODE env so that user can use it to specify the default max pods per node for the cluster. IP_ALIAS_SIZE will be changed accordingly. Must have ip alias enabled. ([#63466](https://github.com/kubernetes/kubernetes/pull/63466), [@grayluck](https://github.com/grayluck))

  - "routeTableCacheTTLInSeconds"
  ([#86266](https://github.com/kubernetes/kubernetes/pull/86266), [@zqingqing1](https://github.com/zqingqing1)) [SIG Cloud Provider]

- Added a new command line argument `--interactive` to kubectl. The new command line argument lets a user confirm deletion requests per resource interactively. ([#114530](https://github.com/kubernetes/kubernetes/pull/114530), [@ardaguclu](https://github.com/ardaguclu)) [SIG CLI and Testing]
- Added a new feature gate, `SchedulerQueueingHints` (enabled by default).

  - `kubectl` outputs warnings to stderr, and accepts a `--warnings-as-errors` option to treat warnings as fatal errors
  - `k8s.io/client-go` outputs warnings to stderr by default; override this per-client by setting `config.WarningHandler`, or per-process with `rest.SetDefaultWarningHandler()`

- For raw block CSI volumes on Kubernetes, kubelet was incorrectly calling CSI NodeStageVolume for every single "map" (i.e. raw block "mount") operation for a volume already attached to the node. This PR ensures it is only called once per volume per node. ([#112403](https://github.com/kubernetes/kubernetes/pull/112403), [@akankshakumari393](https://github.com/akankshakumari393)) [SIG Storage]

- 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))

- github.com/hashicorp/mdns: [v1.0.0](https://github.com/hashicorp/mdns/tree/v1.0.0)
- github.com/hashicorp/memberlist: [v0.1.3](https://github.com/hashicorp/memberlist/tree/v0.1.3)
- github.com/hashicorp/serf: [v0.8.2](https://github.com/hashicorp/serf/tree/v0.8.2)
- github.com/jmespath/go-jmespath/internal/testify: [v1.5.1](https://github.com/jmespath/go-jmespath/internal/testify/tree/v1.5.1)