* kubeadm now produces error during preflight checks if swap is enabled. Users, who can setup kubelet to run in unsupported environment with enabled swap, will be able to skip that preflight check. ([#55399](https://github.com/kubernetes/kubernetes/pull/55399), [@kad](https://github.com/kad))

- Fixes a goroutine leak in kube-apiserver when a request times out. ([#83333](https://github.com/kubernetes/kubernetes/pull/83333), [@lavalamp](https://github.com/lavalamp))
- Fixes the bug in informer-gen that it produces incorrect code if a type has nonNamespaced tag set. ([#80458](https://github.com/kubernetes/kubernetes/pull/80458), [@tatsuhiro-t](https://github.com/tatsuhiro-t))

* Flex drivers by default do not produce metrics. Flex plugins can enable metrics collection by setting  the capability 'supportsMetrics' to true. Make sure the file system can support fs stat to produce metrics in this case. ([#67508](https://github.com/kubernetes/kubernetes/pull/67508), [@brahmaroutu](https://github.com/brahmaroutu))

- Graduated the `LegacyServiceAccountTokenTracking` feature gate to GA. The usage of auto-generated secret-based service account token now produces warnings, and relevant Secrets are labeled with a last-used timestamp (label key `kubernetes.io/legacy-token-last-used`). ([#117591](https://github.com/kubernetes/kubernetes/pull/117591), [@zshihang](https://github.com/zshihang)) [SIG API Machinery,...

Due to a [tagging bug in our Release Engineering tooling](https://github.com/kubernetes/release/issues/1080) during `v1.18.0-alpha.3`, we needed to push a manual tag (`v1.18.0-alpha.4`).

**No binaries have been produced or will be provided for `v1.18.0-alpha.4`.**

The changelog for `v1.18.0-alpha.4` is included as part of the [changelog since v1.18.0-alpha.3][#changelog-since-v1180-alpha3] section.

# v1.18.0-alpha.3

 - Pods that are considered for preemption and haven't started don't produce an error log. ([#90241](https://github.com/kubernetes/kubernetes/pull/90241), [@alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]

* Add masquerading rules by default to GCE/GKE ([#55178](https://github.com/kubernetes/kubernetes/pull/55178), [@dnardo](https://github.com/dnardo))

  The `DeclarativeValidationTakeover` feature gate remains disabled by default.  While disabled, validation errors produced by hand written validation are always return to the caller.  To switch to declarative validation is primary source of errors for migrated fields, enable this feature gate. ([#130728](https://github.com/kubernetes/kubernetes/pull/130728), [@jpbet...

  can also be scheduled to nodes with `GA` labels. ([#118923](https://github.com/kubernetes/kubernetes/pull/118923), [@AxeZhan](https://github.com/AxeZhan))
- Updated the generic apiserver library to produce an error if a new API server is configured with support for a data format other than JSON, YAML, or Protobuf. ([#121325](https://github.com/kubernetes/kubernetes/pull/121325), [@benluddy](https://github.com/benluddy)) [SIG API Machinery]

- Graduated the `LegacyServiceAccountTokenTracking` feature gate to Beta. The usage of auto-generated secret-based service account token now produces warnings by default, and relevant Secrets are labeled with a last-used timestamp (label key `kubernetes.io/legacy-token-last-used`). ([#114523](https://github.com/kubernetes/kubernetes/pull/114523), [@zshihang](https://github.com/zshihang)) [SIG...