- Kubeadm: fix a bug where file copy(backup) could not be executed correctly on Windows platform during upgrade ([#117861](https://github.com/kubernetes/kubernetes/pull/117861), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]

  a bug in the transforming informer during the Resync operation, 
  by making the transforming function idempotent. ([#124352](https://github.com/kubernetes/kubernetes/pull/124352), [@wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery and Scheduling]

### Instrumentation

In v1.9 we focused on improving stability of the components owned by the SIG, including Heapster, Custom Metrics API adapters for Prometheus, and Stackdriver.

- Sync node status during kubelet node shutdown.
  Adds an pod admission handler that rejects new pods when the node is in progress of shutting down. ([#98005](https://github.com/kubernetes/kubernetes/pull/98005), [@wzshiming](https://github.com/wzshiming)) [SIG Node]

    * ServiceDelimiter string Delimiter to use to separate overridden services (multiple services) Defaults to "&"
    * ServicenameDelimiter string Delimiter to use to separate servicename from its configuration parameters Defaults "|"
    * OverrideSeparator string Delimiter to use to separate region of occurrence, url and signing region for each override Defaults to ","

- Remove ready file and its directory (which is created during volume SetUp) during emptyDir volume TearDown. ([#95770](https://github.com/kubernetes/kubernetes/pull/95770), [@jingxu97](https://github.com/jingxu97)) [SIG Storage]

### Other (Cleanup or Flake)

  // +optional
  optional string initiatorName = 12;
}

// Maps a string key to a path within a volume.
message KeyToPath {
  // key is the key to project.
  optional string key = 1;

  // path is the relative path of the file to map the key to.
  // May not be an absolute path.
  // May not contain the path element '..'.
  // May not start with the string '..'.
  optional string path = 2;

- OIDC authentication will now fail if the username asserted based on a CEL expression config is the empty string.  Previously the request would be authenticated with the username set to the empty string. ([#123568](https://github.com/kubernetes/kubernetes/pull/123568), [@enj](https://github.com/enj))

  Don't use these flags. Using deprecated flags causes the server to print a warning. Using a removed flag causes the server to abort the startup.

* The following deprecated flags were removed from `kubelet`:

  * `api-servers` - add apiserver addresses to the kubeconfig file instead.

  
    A previous release built hyperkube using the debian-hyperkube-base@v1.0.0,
    which was updated to address a CVE in the CNI plugins.
    
    A side-effect of using this new image was that the networking packages
    (namely `iptables`) drifted from the versions used in the kube-proxy images.
  
    The following issues were filed on kube-proxy failures when using hyperkube: