* Native support for token based bootstrap flow.  This includes signing a well known ConfigMap in the `kube-public` namespace and cleaning out expired tokens. ([#36101](https://github.com/kubernetes/kubernetes/pull/36101), [@jbeda](https://github.com/jbeda))

### ConfigMap

kube-controller-manager has dropped support for the `--insecure-experimental-approve-all-kubelet-csrs-for-group` flag. It is accepted in 1.7, but ignored. Instead, the csrapproving controller uses authorization checks to determine whether to approve certificate signing requests: ([#45619](https://github.com/kubernetes/kubernetes/pull/45619), [@mikedanese](https://github.com/mikedanese))

    * Before upgrading, users must ensure their controller manager will enable the csrapproving controller, create...

    * OverrideSeparator string Delimiter to use to separate region of occurrence, url and signing region for each override Defaults to ","
    * ServiceOverrides string example: s3|region1, https://s3.foo.bar, some signing_region & ec2|region2, https://ec2.foo.bar, signing_region

  - The requested name did not match the set of authorized names (`x509.HostnameError`)
  - The error surfaced after attempting a connection contained one of the substrings: "certificate is not trusted" or "certificate signed by unknown authority". ([#120736](https://github.com/kubernetes/kubernetes/pull/120736), [@MadhavJivrajani](https://github.com/MadhavJivrajani))

  - The requested name does not match the set of authorized names (x509.HostnameError)
  - The error surfaced after attempting a connection contains one of the substrings: "certificate is not trusted" or "certificate signed by unknown authority" ([#120766](https://github.com/kubernetes/kubernetes/pull/120766), [@MadhavJivrajani](https://github.com/MadhavJivrajani)) [SIG Architecture and Cloud Provider]