Merge pull request #21674 from cloudmelon/melonbranch

Add node lease namespace

Author: k8s-ci-robot

content/en/docs/concepts/overview/working-with-objects/namespaces.md

@@ -58,12 +58,13 @@ kube-public       Active   1d
 kube-system       Active   1d
 ```
 
-Kubernetes starts with three initial namespaces:
+Kubernetes starts with four initial namespaces:
 
    * `default` The default namespace for objects with no other namespace
    * `kube-system` The namespace for objects created by the Kubernetes system
    * `kube-public` This namespace is created automatically and is readable by all users (including those not authenticated). This namespace is mostly reserved for cluster usage, in case that some resources should be visible and readable publicly throughout the whole cluster. The public aspect of this namespace is only a convention, not a requirement.
-
+   * `kube-node-lease` This namespace for the lease objects associated with each node which improves the performance of the node heartbeats as the cluster scales.
+   
 ### Setting the namespace for a request
 
 To set the namespace for a current request, use the `--namespace` flag.