[OCPBUGS-48096]: HCP proxy docs for mgmt clusters with secondary networks

Author: lahinson

hosted_control_planes/hcp-networking.adoc

@@ -18,6 +18,8 @@ include::modules/hcp-proxy-ignition.adoc[leveloffset=+1]
 include::modules/hcp-proxy-api.adoc[leveloffset=+1]
 //cp workloads that need access to external services and must use the proxy for the management cluster
 include::modules/hcp-proxy-mgmt-cluster.adoc[leveloffset=+1]
+//proxy configuration on the mgmt cluster when the hosted cluster has a secondary network and no default pod network
+include::modules/hcp-proxy-addl-network.adoc[leveloffset=+1]
 
 [role="_additional-resources"]
 [id="additional-resources_{context}"]

modules/hcp-proxy-addl-network.adoc

@@ -0,0 +1,9 @@
+// Module included in the following assemblies:
+//
+// * hosted_control_planes/hcp-networking.adoc
+
+:_mod-docs-content-type: CONCEPT
+[id="hcp-proxy-addl-network_{context}"]
+= Management cluster using a proxy and a hosted cluster with a secondary network and no default pod network
+
+If a management cluster uses a proxy configuration and you are configuring a hosted cluster with a secondary network but are not attaching the default pod network, add the CIDR of the secondary network to the proxy configuration. Specifically, you need to add the CIDR of the secondary network to the `noProxy` section of the proxy configuration for the management cluster. Otherwise, the Kubernetes API server will route some API requests through the proxy. In the hosted cluster configuration, the CIDR of the secondary network is automatically added to the `noProxy` section.