### **Multicluster**

*   Development of Kubernetes Federation has moved to [github.com/kubernetes/federation](https://github.com/kubernetes/federation). This move out of tree also means that Federation will begin releasing separately from Kubernetes. Impact:
    *   Federation-specific behavior will no longer be included in kubectl
    *   kubefed will no longer be released as part of Kubernetes

- Introduces a new GCE specific cluster creation variable KUBE_PROXY_DISABLE. When set to true, this will skip over the creation of kube-proxy (whether the daemonset or static pod). This can be used to control the lifecycle of kube-proxy separately from the lifecycle of the nodes. ([#91977](https://github.com/kubernetes/kubernetes/pull/91977), [@varunmar](https://github.com/varunmar)) [SIG Cloud Provider]
- Kube-apiserver now maintains a Lease object to identify itself: 

- The `kubelet` now reports distinguishes log messages about certificate rotation for its client cert and server cert separately to make debugging problems with one or the other easier. ([#101252](https://github.com/kubernetes/kubernetes/pull/101252), [@smarterclayton](https://github.com/smarterclayton))

#### New API fields:

0x1.5e-2     // invalid: hexadecimal mantissa requires p exponent
1_.5         // invalid: _ must separate successive digits
1._5         // invalid: _ must separate successive digits
1.5_e1       // invalid: _ must separate successive digits
1.5e_1       // invalid: _ must separate successive digits
1.5e1_       // invalid: _ must separate successive digits
</pre>


<h3 id="Imaginary_literals">Imaginary literals</h3>

<p>

  * Passing multiple values separated by a comma in a single --from-literal flag is no longer supported. Please use multiple --from-literal flags to provide multiple values.

address of the service account directly. (This is a breaking change if the numeric uniqueIDs of the Google service accounts were being used in RBAC role bindings. The behavior can be overridden by explicitly specifying the scope values as comma-separated string in the "users[*].config.scopes" field in the KUBECONFIG file.) This way, users can now  set a Google Service Account JSON key in the  GOOGLE_APPLICATION_CREDENTIALS environment variable, craft a kubeconfig file with GKE master IP+CA cert,...

### kubectl (CLI)
* `kubectl create role` and  `kubectl create clusterrole`  invocations must be updated to specify multiple resource names as repeated  `--resource-name` arguments instead of comma-separated arguments to a single `--resource-name` argument. E.g. `--resource-name=x,y` must become `--resource-name x --resource-name y` ([#44950](https://github.com/kubernetes/kubernetes/pull/44950), [@xilabao](https://github.com/xilabao))

plugin is enabled.([#51436](https://github.com/kubernetes/kubernetes/pull/51436))

* [Action required] The validation rule for metadata.initializers.pending[x].name is tightened. The initializer name must contain at least three segments, separated by dots. You can create objects with pending initializers and not rely on the API server to add pending initializers according to `initializerConfiguration`. If you do so, update the initializer name in the existing objects and the configuration...

- The `CloudDualStackNodeIPs` feature is now `beta`, meaning that when using
  an external cloud provider that has been updated to support the feature,
  you can pass comma-separated dual-stack `--node-ips` to `kubelet` and have
  the cloud provider take both IPs into account. ([#120275](https://github.com/kubernetes/kubernetes/pull/120275), [@danwinship](https://github.com/danwinship))