Add documentation for RAID feature

In OCP4.10, the feature of configuring the RAID of the worker node in the process of IPI has been added.
Add corresponding documents for detailed description.

Signed-off-by: Zhou Hao <[email protected]>

Author: zhouhao3

installing/installing_bare_metal_ipi/ipi-install-installation-workflow.adoc

@@ -53,6 +53,8 @@ ifeval::[{product-version} > 4.8]
 include::modules/ipi-install-configuring-bios-for-worker-node.adoc[leveloffset=+2]
 endif::[]
 
+include::modules/ipi-install-configuring-raid-for-worker-node.adoc[leveloffset=+2]
+
 include::modules/ipi-install-creating-a-disconnected-registry.adoc[leveloffset=+1]
 
 include::modules/ipi-install-deploying-routers-on-worker-nodes.adoc[leveloffset=+1]

modules/ipi-install-configuring-raid-for-worker-node.adoc

@@ -0,0 +1,54 @@
+// Module included in the following assemblies:
+//
+// * installing/installing_bare_metal_ipi/ipi-install-configuration-files.adoc
+[id="configuring-raid-for-worker-node_{context}"]
+= Configuring RAID for worker node
+
+The following procedure configures RAID (Redundant Array of Independent Disks) for the worker node during the installation process.
+
+[NOTE]
+====
+. Only servers with BMC (Baseboard Management Controller) type `irmc` are supported. Other types of servers are currently not supported.
+. If you want to configure hardware RAID for the server, make sure the server has a RAID controller.
+====
+
+.Procedure
+. Create manifests.
+. Modify the BMH (Bare Metal Host) file corresponding to the worker:
++
+[source,terminal]
+----
+$ vim clusterconfigs/openshift/99_openshift-cluster-api_hosts-3.yaml
+----
++
+[NOTE]
+====
+Because servers with BMC type `irmc` do not support software RAID, the following RAID configuration uses hardware RAID as an example.
+====
++
+.. If you added specific RAID configuration to the spec, this causes the worker node to delete the original RAID configuration in the `preparing` phase and perform a specified configuration on the RAID. For example:
++
+[source,yaml]
+----
+spec:
+  raid:
+    hardwareRAIDVolumes:
+    - level: "0"
+      name: "sda"
+      numberOfPhysicalDisks: 1
+      rotational: true
+      sizeGibibytes: 0
+----
+<1> `level` is a required field, and the others are optional fields.
++
+.. If you added an empty RAID configuration to the spec, this empty configuration causes the worker node to delete the original RAID configuration during the `preparing` phase, but does not perform a new configuration. For example:
++
+[source,yaml]
+----
+spec:
+  raid:
+    hardwareRAIDVolumes: []
+----
++
+.. If you do not add a `raid` field in the spec, the original RAID configuration is not deleted, and no new configuration will be performed.
+. Create cluster.