### 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

or `/etc/sysconfig/kubelet`, depending on the system you're running on.
([#64780](https://github.com/kubernetes/kubernetes/pull/64780), [@luxas](https://github.com/luxas))

* AWS volumes: Use /dev/xvdXX names with EC2 ([#27628](https://github.com/kubernetes/kubernetes/pull/27628), [@justinsb](https://github.com/justinsb))
* Add a test config variable to specify desired Docker version to run on GCI. ([#26813](https://github.com/kubernetes/kubernetes/pull/26813), [@wonderfly](https://github.com/wonderfly))

- The certificate signer no longer accepts ca.key passwords via the `CFSSL_CA_PK_PASSWORD` environment variable. This capability was not prompted by user request, never advertised, and recommended against in the security audit. ([#84677](https://github.com/kubernetes/kubernetes/pull/84677), [@mikedanese](https://github.com/mikedanese))

- Adds `OpenAPIV3SchemaInterface` to `DiscoveryClient` and its variants for fetching OpenAPI v3 schema documents. ([#108992](https://github.com/kubernetes/kubernetes/pull/108992), [@alexzielenski](https://github.com/alexzielenski))

- New `KUBECACHEDIR` environment variable was introduced to override default discovery cache directory which is `$HOME/.kube/cache`. ([#109479](https://github.com/kubernetes/kubernetes/pull/109479), [@ardaguclu](https://github.com/ardaguclu))

    public void addDocumentSettingRewriteRule(final UnaryOperator<String> rule) {
        docSettingRewriteRuleList.add(rule);
    }

    /**
     * Gets the resource path for configuration files, checking type-specific variants first.
     *
     * @param basePath the base path for resources
     * @param type     the search engine type
     * @param path     the relative path to the resource
     * @return the full resource path
     */

- 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),...

    * inherit the environment from the primary process, so if the container was created with tty=false,that means the exec session's TERM variable will default to "dumb". Users can override this by setting TERM=xterm (or whatever is appropriate) to get the correct "smart" terminal behavior.

* The kube-apiserver [basic audit log](https://kubernetes.io/docs/admin/audit/) can be enabled in GCE by exporting the environment variable `ENABLE_APISERVER_BASIC_AUDIT=true` before running `cluster/kube-up.sh`. This will log to `/var/log/kube-apiserver-audit.log` and use the same `logrotate` settings as `/var/log/kube-apiserver.log`. ([#41211](https://github.com/kubernetes/kubernetes/pull/41211),...