- **Federation**
  - [alpha] Support for ConfigMaps in federation. ([docs](http://kubernetes.io/docs/user-guide/federation/configmap/)) ([kubernetes/features#105](https://github.com/kubernetes/enhancements/issues/105))

  
  To allow cgroups v1 with `kubeadm` and `kubelet` version `v1.35` or newer, you must:
  - Ignore the error from the SystemVerification preflight check by `kubeadm`.
  - Edit the `kube-system/kubelet-config` ConfigMap and add the `failCgroupV1: false` field before upgrading. ([#134744](https://github.com/kubernetes/kubernetes/pull/134744), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle and Node]
 
## Changes by Kind

* Add density (batch pods creation latency and resource) and resource performance tests to `test-e2e-node' ([#29764](https://github.com/kubernetes/kubernetes/pull/29764), [@coufon](https://github.com/coufon))
* Allow Secret & ConfigMap keys to contain caps, dots, and underscores ([#25458](https://github.com/kubernetes/kubernetes/pull/25458), [@errm](https://github.com/errm))