k8s.io/client-go no longer default to a server address of `http://localhost:8080`. If you own one of these legacy clusters, you are *strongly* encouraged to secure your server. If you cannot secure your server, you can set the `$KUBERNETES_MASTER` environment variable to `http://localhost:8080` to continue defaulting the server address. `kubectl` users can also set the server address using the `--server` flag, or in a kubeconfig file specified via `--kubeconfig` or `$KUBECONFIG`. ([#86173](https://github.com/...

* Enable AttachVolumeLimit feature ([#69225](https://github.com/kubernetes/kubernetes/pull/69225), [@gnufied](https://github.com/gnufied))
* [GCP] Added env variables to control CPU requests of kube-controller-manager and kube-scheduler. ([#68823](https://github.com/kubernetes/kubernetes/pull/68823), [@loburm](https://github.com/loburm))

### External credential provider for client-go

The client-go credential plugins can now be passed in the current cluster information via the `KUBERNETES_EXEC_INFO` environment variable. Learn more about this on [client-go credential plugins documentation](https://docs.k8s.io/reference/access-authn-authz/authentication/#client-go-credential-plugins/).

### CronJob controller v2 is available through feature gate

- Kubeadm: now sets the host `OS` environment variables when executing `crictl` during image pulls. This fixed a bug where `*PROXY` environment variables did not affect `crictl` internet connectivity. ([#110134](https://github.com/kubernetes/kubernetes/pull/110134), [@mk46](https://github.com/mk46))

- Users should not rely on unsupported CRON_TZ variable when specifying schedule, both the API server and cronjob controller will emit warnings pointing to https://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/ containing explanation ([#106455](https://github.com/kubernetes/kubernetes/pull/106455),...

* Remove environment variables and internal Kubernetes Docker labels from cAdvisor Prometheus metric labels. ([#31064](https://github.com/kubernetes/kubernetes/pull/31064), [@grobie](https://github.com/grobie))
    * Old behavior:

-...

- When using the conformance test image, a new environment variable `E2E_USE_GO_RUNNER` will cause the tests to be run with the new golang-based test runner rather than the current bash wrapper. ([#79284](https://github.com/kubernetes/kubernetes/pull/79284), [@johnSchnake](https://github.com/johnSchnake))

of treating the CommonName field on X.509 serving certificates as a host name when no Subject Alternative Names are present is now disabled by default. It can be temporarily re-enabled by adding the value x509ignoreCN=0 to the GODEBUG environment variable. ([#93264](https://github.com/kubernetes/kubernetes/pull/93264), [@justaugustus](https://github.com/justaugustus)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Release, Scalability, Storage and...

    * If you are running E2E tests which require SSH keys and you utilize environment variables to override their location, you may need to modify the environment variable set. On all providers the environment variable override can now be either an absolute path to the key or a relative path (relative to ~/.ssh). Specifically the changes are: