- kubeadm: Allowed to download certificate secrets uploaded by `init` or `upload-certs` phase, allowing to transfer certificate secrets (certificates and keys) from the cluster to other master machines when creating HA deployments. ([#74168](https://github.com/kubernetes/kubernetes/pull/74168), [@ereslibre](https://github.com/ereslibre))...

### Secrets
* Populate environment variables from a secrets. ([#39446](https://github.com/kubernetes/kubernetes/pull/39446), [@fraenkel](https://github.com/fraenkel))

```
kubectl --namespace=federation get secret federation-apiserver-secret -o json | sed 's/federation-apiserver-secret/federation-apiserver-kubeconfig/g' | kubectl create -f -
# optionally, remove the old secret
kubectl delete secret --namespace=federation federation-apiserver-secret
```

### Immutable Secrets and ConfigMaps

Immutable Secrets and ConfigMaps graduates to GA. This feature allows users to specify that the contents of a particular Secret or ConfigMap is immutable for its object lifetime. For such instances, Kubelet will not watch/poll for changes and therefore reducing apiserver load.

* Add federation api and cm servers to hyperkube ([#27586](https://github.com/kubernetes/kubernetes/pull/27586), [@colhom](https://github.com/colhom))
* federation: Creating kubeconfig files to be used for creating secrets for clusters on aws and gke ([#27332](https://github.com/kubernetes/kubernetes/pull/27332), [@nikhiljindal](https://github.com/nikhiljindal))

### CVE-2023-2728: Bypassing enforce mountable secrets policy imposed by the ServiceAccount admission plugin

  - [Changelog since v1.28.8](#changelog-since-v1288)
  - [Important Security Information](#important-security-information-1)
    - [CVE-2024-3177: Bypassing mountable secrets policy imposed by the ServiceAccount admission plugin](#cve-2024-3177-bypassing-mountable-secrets-policy-imposed-by-the-serviceaccount-admission-plugin)
  - [Changes by Kind](#changes-by-kind-6)
    - [Feature](#feature-4)
    - [Bug or Regression](#bug-or-regression-6)

specified as environment variables. When we convert the OpenStack cloud provider to run in an external process, we can now use the kubernetes Secrets capability to inject the OS_* variables. This way we can specify the cloud configuration as a configmap, and specify secrets for the userid/password information. The configmap is mounted as a file, and the secrets are made available as environment variables. The external controller itself runs as a pod/daemonset. For backward compatibility, we preload...

## Kubefed

* Deprecate the `--secret-name` flag from `kubefed join`, instead generating the secret name arbitrarily. ([#42513](https://github.com/kubernetes/kubernetes/pull/42513), [@perotinus](https://github.com/perotinus))


### **Kubernetes API**
#### User Provided Extensions

* ACTION REQUIRED: Azure cloud provider could now be configured by Kubernetes secrets and a new option `cloudConfigType` is introduced, whose candidate values are `file`, `secret` and `merge` (default is `merge`). Note that the secret is a serialized version of azure.json file with key cloud-config. And the secret name is azure-cloud-provider in kube-system namespace. To allow Azure cloud provider read this secret, the RBAC permission referred [here](https://github.com/kubernetes/kubernetes/pull/78242)...