Added section on operators for nodeAffinity and podAffinity (#39742)

* Added section in the docs about the behaviour of operator in the node and pod affinity docs

* Fixes from review

* Fixed podAffinity and added note about non-integer values

* Fixes from review

* Fixed review comments

* Fixes from review

Author: sreeram-venkitesh

content/en/docs/concepts/scheduling-eviction/assign-pod-node.md

@@ -135,6 +135,9 @@ You can use the `operator` field to specify a logical operator for Kubernetes to
 interpreting the rules. You can use `In`, `NotIn`, `Exists`, `DoesNotExist`,
 `Gt` and `Lt`.
 
+Read [Operators](#operators)
+to learn more about how these work.
+
 `NotIn` and `DoesNotExist` allow you to define node anti-affinity behavior.
 Alternatively, you can use [node taints](/docs/concepts/scheduling-eviction/taint-and-toleration/)
 to repel Pods from specific nodes.
@@ -310,6 +313,9 @@ refer to the [design proposal](https://git.k8s.io/design-proposals-archive/sched
 You can use the `In`, `NotIn`, `Exists` and `DoesNotExist` values in the
 `operator` field for Pod affinity and anti-affinity.
 
+Read [Operators](#operators)
+to learn more about how these work.
+
 In principle, the `topologyKey` can be any allowed label key with the following
 exceptions for performance and security reasons:
 
@@ -492,6 +498,31 @@ overall utilization.
 Read [Pod topology spread constraints](/docs/concepts/scheduling-eviction/topology-spread-constraints/)
 to learn more about how these work.
 
+## Operators
+
+The following are all the logical operators that you can use in the `operator` field for `nodeAffinity` and `podAffinity` mentioned above.
+
+|    Operator    |    Behavior     |
+| :------------: | :-------------: |
+| `In` | The label value is present in the supplied set of strings |
+|   `NotIn`   | The label value is not contained in the supplied set of strings |
+| `Exists` | A label with this key exists on the object |
+| `DoesNotExist` | No label with this key exists on the object |
+
+The following operators can only be used with `nodeAffinity`.
+
+|    Operator    |    Behaviour    |
+| :------------: | :-------------: |
+| `Gt` | The supplied value will be parsed as an integer, and that integer is less than or equal to the integer that results from parsing the value of a label named by this selector | 
+| `Lt` | The supplied value will be parsed as an integer, and that integer is greater than or equal to the integer that results from parsing the value of a label named by this selector | 
+
+
+{{<note>}}
+`Gt` and `Lt` operators will not work with non-integer values. If the given value 
+doesn't parse as an integer, the pod will fail to get scheduled. Also, `Gt` and `Lt` 
+are not available for `podAffinity`.
+{{</note>}}
+
 ## {{% heading "whatsnext" %}}
 
 - Read more about [taints and tolerations](/docs/concepts/scheduling-eviction/taint-and-toleration/) .