Merge pull request #33836 from mikemckiernan/feat-egress-router-cr

Restore SDN to OVN migration intro

Author: mikemckiernan

modules/nw-ovn-kubernetes-migration-about.adoc

@@ -1,3 +1,21 @@
+// Module included in the following assemblies:
+//
+// * networking/ovn_kubernetes_network_provider/migrate-from-openshift-sdn.adoc
+
+[id="nw-ovn-kubernetes-migration-about_{context}"]
+= Migration to the OVN-Kubernetes network provider
+
+Migrating to the OVN-Kubernetes Container Network Interface (CNI) cluster network provider is a manual process that includes some downtime during which your cluster is unreachable. Although a rollback procedure is provided, the migration is intended to be a one-way process.
+
+[id="considerations-migrating-ovn-kubernetes-network-provider_{context}"]
+== Considerations for migrating to the OVN-Kubernetes network provider
+
+The subnets assigned to nodes and the IP addresses assigned to individual pods are not preserved during the migration.
+
+While the OVN-Kubernetes network provider implements many of the capabilities present in the OpenShift SDN network provider, the configuration is not the same.
+
+* If your cluster uses any of the following OpenShift SDN capabilities, you must manually configure the same capability in OVN-Kubernetes:
++
 --
 * Namespace isolation
 * Egress IP addresses