Merge pull request #29102 from mburke5678/BZ-1846671

Highlight relantionship between defaultNodeSelector and pod's nodeSelector

Author: mburke5678

modules/nodes-scheduler-node-selectors-pod.adoc

@@ -12,6 +12,8 @@ With node selectors, {product-title} schedules the pods on nodes that contain ma
 To add node selectors to an existing pod, add a node selector to the controlling object for that pod, such as a `ReplicaSet` object, `DaemonSet` object, `StatefulSet` object, `Deployment` object, or `DeploymentConfig` object.
 Any existing pods under that controlling object are recreated on a node with a matching label. If you are creating a new pod, you can add the node selector directly to the `Pod` spec.
 
+If you use cluster-wide node selectors, when you create a pod in that cluster, {product-title} adds the default node selectors to the pod and schedules the pod on nodes with labels that match the default node selectors and the pod node selectors.
+
 You can add labels to a node or machine config, but the labels will not persist if the node or machine goes down.
 Adding the label to the machine set ensures that new nodes or machines will have the label.
 

nodes/scheduling/nodes-scheduler-default.adoc

@@ -42,7 +42,7 @@ spec:
   defaultNodeSelector: type=user-node,region=east <2>
 ----
 <1> You can specify the name of a custom scheduler policy file.
-<2> Optionally, specify a default node selector to restrict pod placement to specific nodes.
+<2> Optional: Specify a default node selector to restrict pod placement to specific nodes. The default node selector is applied to the pods created in all namespaces. Pods can be scheduled on nodes with labels that match the default node selector and any existing pod node selectors. Namespaces having project-wide node selectors are not impacted even if this field is set. 
 
 // The following include statements pull in the module files that comprise
 // the assembly. Include any combination of concept, procedure, or reference