Add the instruction on how to configure nodeSelector, tolerations and affinity (#4277)

* Add the instruction on how to configure nodeSelector, tolerations and affinity

* Keep the docs consistent in terms of the syntax

docs/admin/install/operator/configuring-eventing-cr.md

@@ -10,8 +10,6 @@ aliases:
 
 You can configure the Knative Eventing operator by modifying settings in the KnativeEventing custom resource (CR).
 
-**NOTE:** Kubernetes spec level policies cannot be configured using the Knative Operators.
-
 <!--TODO: break this into sub sections like for the channels sections, i.e. a page per topic-->
 
 ## Installing a specific version of Eventing
@@ -316,3 +314,100 @@ spec:
       cpu: 1000m
       memory: 250Mi
 ```
+
+### Override the nodeSelector
+
+The KnativeEventing resource is able to override the nodeSelector for the Knative Eventing deployment resources.
+For example, if you would like to add the following tolerations
+
+```yaml
+nodeSelector:
+  disktype: hdd
+```
+
+to the deployment `eventing-controller`, you need to change your KnativeEventing CR as below:
+
+```yaml
+apiVersion: operator.knative.dev/v1alpha1
+kind: KnativeEventing
+metadata:
+  name: knative-eventing
+  namespace: knative-eventing
+spec:
+  deployments:
+  - name: eventing-controller
+    nodeSelector:
+      disktype: hdd
+```
+
+### Override the tolerations
+
+The KnativeEventing resource is able to override tolerations for the Knative Eventing deployment resources.
+For example, if you would like to add the following tolerations
+
+```yaml
+tolerations:
+- key: "key1"
+  operator: "Equal"
+  value: "value1"
+  effect: "NoSchedule"
+```
+
+to the deployment `eventing-controller`, you need to change your KnativeEventing CR as below:
+
+```yaml
+apiVersion: operator.knative.dev/v1alpha1
+kind: KnativeEventing
+metadata:
+  name: knative-eventing
+  namespace: knative-eventing
+spec:
+  deployments:
+  - name: eventing-controller
+    tolerations:
+    - key: "key1"
+      operator: "Equal"
+      value: "value1"
+      effect: "NoSchedule"
+```
+
+### Override the affinity
+
+The KnativeEventing resource is able to override the affinity, including nodeAffinity, podAffinity, and podAntiAffinity,
+for the Knative Eventing deployment resources. For example, if you would like to add the following nodeAffinity
+
+```yaml
+affinity:
+  nodeAffinity:
+    preferredDuringSchedulingIgnoredDuringExecution:
+    - weight: 1
+      preference:
+        matchExpressions:
+        - key: disktype
+          operator: In
+          values:
+          - ssd
+```
+
+to the deployment `activator`, you need to change your KnativeEventing CR as below:
+
+```yaml
+apiVersion: operator.knative.dev/v1alpha1
+kind: KnativeEventing
+metadata:
+  name: knative-eventing
+  namespace: knative-eventing
+spec:
+  deployments:
+  - name: activator
+    affinity:
+      nodeAffinity:
+        preferredDuringSchedulingIgnoredDuringExecution:
+        - weight: 1
+          preference:
+            matchExpressions:
+            - key: disktype
+              operator: In
+              values:
+              - ssd
+```

docs/admin/install/operator/configuring-serving-cr.md

@@ -468,7 +468,7 @@ while other system deployments have `2` Replicas by using `spec.high-availabilit
 apiVersion: operator.knative.dev/v1alpha1
 kind: KnativeServing
 metadata:
-  name: ks
+  name: knative-serving
   namespace: knative-serving
 spec:
   high-availability:
@@ -485,7 +485,7 @@ spec:
 !!! note
     The KnativeServing resource `label` and `annotation` settings override the webhook's labels and annotations for both Deployments and Pods.
 
-### Override nodeSelector
+### Override the nodeSelector
 
 The following KnativeServing resource overrides the `webhook` deployment to use the `disktype: hdd` nodeSelector:
 
@@ -493,7 +493,7 @@ The following KnativeServing resource overrides the `webhook` deployment to use
 apiVersion: operator.knative.dev/v1alpha1
 kind: KnativeServing
 metadata:
-  name: ks
+  name: knative-serving
   namespace: knative-serving
 spec:
   deployments:
@@ -501,3 +501,75 @@ spec:
     nodeSelector:
       disktype: hdd
 ```
+
+### Override the tolerations
+
+The KnativeServing resource is able to override tolerations for the Knative Serving deployment resources.
+For example, if you would like to add the following tolerations
+
+```yaml
+tolerations:
+- key: "key1"
+  operator: "Equal"
+  value: "value1"
+  effect: "NoSchedule"
+```
+
+to the deployment `activator`, you need to change your KnativeServing CR as below:
+
+```yaml
+apiVersion: operator.knative.dev/v1alpha1
+kind: KnativeServing
+metadata:
+  name: knative-serving
+  namespace: knative-serving
+spec:
+  deployments:
+  - name: activator
+    tolerations:
+    - key: "key1"
+      operator: "Equal"
+      value: "value1"
+      effect: "NoSchedule"
+```
+
+### Override the affinity
+
+The KnativeServing resource is able to override the affinity, including nodeAffinity, podAffinity, and podAntiAffinity,
+for the Knative Serving deployment resources. For example, if you would like to add the following nodeAffinity
+
+```yaml
+affinity:
+  nodeAffinity:
+    preferredDuringSchedulingIgnoredDuringExecution:
+    - weight: 1
+      preference:
+        matchExpressions:
+        - key: disktype
+          operator: In
+          values:
+          - ssd
+```
+
+to the deployment `activator`, you need to change your KnativeServing CR as below:
+
+```yaml
+apiVersion: operator.knative.dev/v1alpha1
+kind: KnativeServing
+metadata:
+  name: knative-serving
+  namespace: knative-serving
+spec:
+  deployments:
+  - name: activator
+    affinity:
+      nodeAffinity:
+        preferredDuringSchedulingIgnoredDuringExecution:
+        - weight: 1
+          preference:
+            matchExpressions:
+            - key: disktype
+              operator: In
+              values:
+              - ssd
+```