OSDOCS-11874-fix: Updated Migrating from the OpenShift SDN network plugin doc to explain webhook prereq

Author: dfitzmau

modules/nw-ovn-kubernetes-migration.adoc

@@ -23,7 +23,8 @@ While performing the migration, your cluster is unavailable and workloads might
 * You can manually reboot each node.
 * You checked that your cluster is in a known good state without any errors.
 * You created a security group rule that allows User Datagram Protocol (UDP) packets on port `6081` for all nodes on all cloud platforms.
-* You set all timeouts for webhooks to `3` seconds or removed the webhooks.
+* You set all timeouts for webhooks to `3` seconds or removed the webhooks. If you did not complete one of these tasks, your cluster might fail to schedule pods.
+** To set a timeout value, you must create a `ValidatingWebhookConfiguration` custom resource and specify the timeout for the `timeoutSeconds` parameter. For more information, see "ValidatingWebhookConfiguration" in the Additional resources section.
 
 .Procedure
 

networking/openshift_sdn/rollback-to-ovn-kubernetes.adoc

@@ -13,3 +13,4 @@ include::snippets/sdn-deprecation-statement.adoc[]
 To learn more about OVN-Kubernetes, read xref:../../networking/ovn_kubernetes_network_provider/about-ovn-kubernetes.adoc#about-ovn-kubernetes[About the OVN-Kubernetes network plugin].
 
 include::modules/nw-ovn-kubernetes-migration.adoc[leveloffset=+1]
+

networking/ovn_kubernetes_network_provider/migrate-from-openshift-sdn.adoc

@@ -50,6 +50,11 @@ include::modules/nw-network-plugin-migration-process.adoc[leveloffset=+2]
 // Migrating to the OVN-Kubernetes network plugin by using the offline migration method
 include::modules/nw-ovn-kubernetes-migration.adoc[leveloffset=+2]
 
+[role="_additional-resources"]
+.Additional resources
+
+* xref:../../rest_api/extension_apis/validatingwebhookconfiguration-admissionregistration-k8s-io-v1.adoc#validatingwebhookconfiguration-admissionregistration-k8s-io-v1[ValidatingWebhookConfiguration [admissionregistration.k8s.io/v1]] 
+
 // Limited live migration to the OVN-Kubernetes network plugin overview
 include::modules/nw-ovn-kubernetes-live-migration-about.adoc[leveloffset=+1]