Merge pull request #264813 from johnmarco/jm-aro-update-multiple-ips

Updates to Multiple IPs per LB article

Author: AnnaMHuff

articles/openshift/howto-multiple-ips.md

@@ -5,18 +5,40 @@ author: johnmarco
 ms.author: johnmarc
 ms.service: azure-redhat-openshift
 ms.topic: article
-ms.date: 12/05/2023
+ms.date: 03/05/2024
 #Customer intent: As an ARO SRE, I need to configure multiple outbound IP addresses per ARO cluster load balancers
 ---
 # Configure multiple IP addresses per ARO cluster load balancer (Preview)
 
 ARO public clusters are created with a public load balancer that's used for outbound connectivity from inside the cluster. By default, one public IP address is configured on that public load balancer, and that limits the maximum node count of your cluster to 62. To be able to scale your cluster to the maximum supported number of nodes, you need to assign multiple additional public IP addresses to the load balancer.
 
-You can configure up to 20 IP addresses per cluster.
+You can configure up to 20 IP addresses per cluster. The outbound rules and frontend IP configurations are adjusted to accommodate the number of IP addresses.
 
-## Requirements (Preview only)
+## Requirements
 
-In order to run the commands in this article, you must first download the aro extension wheel file from [https://aka.ms/az-aroext-latest](https://aka.ms/az-aroext-latest). To install the extension, run the following command:
+The multiple public IPs feature is only available on the current network architecture used by ARO; older clusters don't support this feature. If your cluster was created before OpenShift Container Platform (OCP) version 4.5, this feature isn't available even if you upgraded your OCP version since then.
+
+If you're unsure if your cluster was created before the current version of OCP, use the following commands to check.
+
+To get the cluster managed resource group:
+
+```
+RESOURCEGROUP=aro-rg   # the name of the resource group your cluster is in
+CLUSTER=cluster        # the name of your cluster
+CLUSTER_RESOURCEGROUP=$(az aro show -g $RESOURCEGROUP -n $CLUSTER --query clusterProfile.resourceGroupId -o tsv | awk -F'/' '{print $NF}')
+```
+
+List the network load balancers:
+
+```
+az network lb list -g $CLUSTER_RESOURCEGROUP -o table
+```
+
+If you have a loadbalancer named `$CLUSTER-public-lb`, the cluster has the older network architecture and can't use the multiple public IP feature.
+
+### Download ARO extension wheel file (Preview only)
+
+In order to run the commands in this article, you must first download the ARO extension wheel file from [https://aka.ms/az-aroext-latest](https://aka.ms/az-aroext-latest). To install the extension, run the following command:
 
 `az extension add -s <path to downloaded whl file>`
 
@@ -40,4 +62,4 @@ az aro update --resource-group aroResourceGroup --name aroCluster \
               --load-balancer-managed-outbound-ip-count 4
 ```
 
-You can use this update method to either increase or decrease the number of IPs on a cluster to be between 1 and 20.
+You can use this update method to either increase or decrease the number of IPs on a cluster to be between 1 and 20. Note that scaling down the number of clusters can interrupt the outbound network traffic from the cluster.

articles/openshift/openshift-faq.yml

@@ -30,7 +30,7 @@ sections:
       - question: What is the maximum number of pods in an Azure Red Hat OpenShift cluster?  What is the maximum number of pods per node in Azure Red Hat OpenShift?
         answer: |
           The actual number of supported pods depends on an application’s memory, CPU, and storage requirements.
-          
+                 
           Azure Red Hat OpenShift 4.x has a 250 pod-per-node limit and a 60 compute node limit. These limits cap the maximum number of pods supported in a cluster to 250×60 = 15,000. For a private cluster without any public IPs (for example, created by using [User Defined Routing (UDR)](howto-create-private-cluster-4x.md#create-a-private-cluster-without-a-public-ip-address) and running version 4.11 or higher), the limits are 120 compute nodes and 30,000 pods.
           
       - question: Can a cluster have compute nodes across multiple Azure regions?