Merge pull request #87782 from openshift-cherrypick-robot/cherry-pick-87416-to-enterprise-4.18

[enterprise-4.18] ocpbugs18537: Documenting ingressWithoutClassName alert

_topic_maps/_topic_map.yml

@@ -1656,6 +1656,9 @@ Topics:
   - Name: Configuring ingress cluster traffic using load balancer allowed source ranges
     File: configuring-ingress-cluster-traffic-load-balancer-allowed-source-ranges
     Distros: openshift-enterprise,openshift-origin
+  - Name: Patching existing ingress objects
+    File: configuring-ingress-cluster-patch-fields
+    Distros: openshift-enterprise,openshift-origin
   # Kubernetes NMState (TECHNOLOGY PREVIEW)
 - Name: Kubernetes NMState
   Dir: k8s_nmstate

modules/nw-patch-fields-example.adoc

@@ -0,0 +1,38 @@
+// Module included in the following assemblies:
+//
+// * networking/configuring_ingress_cluster_traffic/configuring-ingress-cluster-patch-fields.adoc
+
+:_mod-docs-content-type: PROCEDURE
+[id="nw-patch-fields-example_{context}"]
+= Patching Ingress objects to resolve an ingressWithoutClassName alert
+
+The `ingressClassName` field specifies the name of the `IngressClass` object. You must define the `ingressClassName` field for each `Ingress` object.
+
+If you have not defined the `ingressClassName` field for an `Ingress` object, you could experience routing issues. After 24 hours, you will receive an `ingressWithoutClassName` alert to remind you to set the `ingressClassName` field.
+
+.Procedure
+
+Patch the `Ingress` objects with a completed `ingressClassName` field to ensure proper routing and functionality.
+
+. List all `IngressClass` objects:
++
+[source,terminal]
+----
+$ oc get ingressclass
+----
+
+. List all `Ingress` objects in all namespaces:
++
+[source,terminal]
+----
+$ oc get ingress -A
+----
+
+. Patch the `Ingress` object:
++
+[source,terminal]
+----
+$ oc patch ingress/<ingress_name> --type=merge --patch '{"spec":{"ingressClassName":"openshift-default"}}'
+----
++ 
+Replace `<ingress_name>` with the name of the `Ingress` object. This command patches the `Ingress` object to include the desired ingress class name.

networking/configuring_ingress_cluster_traffic/configuring-ingress-cluster-patch-fields.adoc

@@ -0,0 +1,19 @@
+:_mod-docs-content-type: ASSEMBLY
+[id="configuring-ingress-cluster-patch-fields"]
+= Patching existing ingress objects
+include::_attributes/common-attributes.adoc[]
+:context: configuring-ingress-cluster-patch-fields
+
+toc::[]
+
+You can update or modify the following fields of existing `Ingress` objects without recreating the objects or disrupting services to them:
+
+* Specifications
+* Host
+* Path
+* Backend services
+* SSL/TLS settings
+* Annotations
+
+// Example: Patching ingress objects with an ingressClassName
+include::modules/nw-patch-fields-example.adoc[leveloffset=+1]