doc: add documentation for nfc

adding documentation for the network
fence class.

Signed-off-by: Madhu Rajanna <[email protected]>

Author: Madhu-1

docs/networkfenceclass.md

@@ -0,0 +1,61 @@
+# NetworkFenceClass
+
+NetworkFence is a cluster-scoped custom resource that allows Kubernetes to invoke "GetFenceClients" operation on a storage provider.
+
+The user needs to specify the csi provisioner name, parameters and the secret required to perform GetFenceClients operation.
+
+## Fence Operation
+
+```yaml
+apiVersion: csiaddons.openshift.io/v1alpha1
+kind: NetworkFenceClass
+metadata:
+  name: network-fence-class
+spec:
+  provisioner: driver.example.com
+  parameters:
+    key: value
+    csiaddons.openshift.io/networkfence-secret-name: secret-name
+    csiaddons.openshift.io/networkfence-secret-namespace: secret-namespace
+```
+
+- `provisioner`: specifies the name of storage provisioner.
+- `parameters`: specifies storage provider specific parameters.
+
+Resereved parameters:
+
+- `csiaddons.openshift.io/networkfence-secret-name`: specifies the name of the secret required for network fencing operation.
+- `csiaddons.openshift.io/networkfence-secret-namespace`: specifies the namespace in which the secret is located.
+
+Once the NetworkFenceClass is processed, the CSI Addons controller will call the GetFenceClients operation on the storage provider associated with the provisioner name that registered the `GET_CLIENTS_TO_FENCE` capability. The resulting data will then be stored in the CSIAddonsNode status.
+
+The NetworkFenceStatus object will contain the list of clients that need to be fenced.
+
+```yaml
+apiVersion: csiaddons.openshift.io/v1alpha1
+kind: CSIAddonsNode
+metadata:
+  annotations:
+    csiaddons.openshift.io/networkfenceclass-names: '["network-fence-class"]'
+  creationTimestamp: "2024-11-11T07:31:20Z"
+  finalizers:
+  - csiaddons.openshift.io/csiaddonsnode
+  generation: 1
+  name: plugin
+  namespace: default
+  ...
+status:
+  capabilities:
+  - service.NODE_SERVICE
+  - reclaim_space.ONLINE
+  - encryption_key_rotation.ENCRYPTIONKEYROTATION
+  - network_fence.GET_CLIENTS_TO_FENCE
+  message: Successfully established connection with sidecar
+  networkFenceClientStatus:
+  - networkFenceClassName: network-fence-class
+    clientDetails:
+    - cidrs:
+      - 10.244.0.1/32
+      id: a815fe8e-eabd-4e87-a6e8-78cebfb67d08
+  state: Connected
+```