This blog describes how to use IBM Cloud Application Load Balancer for Virtual Private Cloud (VPC) and IBM Cloud DNS Services (in the classic infrastructure) with Red Hat OpenShift on IBM Power Systems Virtual Server.

Note: Using IBM Cloud Application Load Balancer for VPC with Power Virtual Server is currently in experimental state.

The following figure provides a high-level overview of the topology.

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Following are the key aspects of the topology:

• IBM Cloud Direct Link 2.0 connectivity is established between Power Virtual Server, IBM Cloud VPC, and IBM Cloud Classic.
• IBM Cloud Application Load Balancer for VPC is used for load balancing the OpenShift control plane and the ingress router.
• IBM Cloud DNS Services in Classic infrastructure is used for the OpenShift cluster domain.

Prerequisites

Make sure that the following prerequisites are fulfilled before using IBM Cloud Application Load Balancer for VPC and IBM Cloud DNS Services (in Classic infrastructure) with Red Hat OpenShift on IBM Power Virtual Server:

• A Power Systems Virtual Server instance

  Refer to the Set up IBM Power Virtual Server for installing Red Hat OpenShift Container Platform guide for creating and setting up the Power Virtual Server service instance for OpenShift.

  Following screen capture shows the Power Virtual Server service instance. This is created in the Frankfurt region.

  

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• RHEL and RHCOS OVA images made available on the IBM Power Systems Virtual Server service instance

  Refer: https://developer.ibm.com/tutorials/preparing-ova-for-openshift-on-cloud/

• VPC and VPC subnet set up on the same region as the Power Virtual Server instance

  Refer to the Using the IBM Cloud console to create VPC resources documentation for creating VPC and VPC subnet.

  The following screen captures show the example VPC and subnet created in the same region (Frankfurt) as the Power Virtual Server instance.

  

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• IBM Cloud Direct Link Connect 2.0 set up between your Power Virtual Server service instance and VPC

  The following screen capture shows the example Direct Link Connect 2.0 connectivity setup between the Power Virtual Server service instance and the VPC (ocp-vpc-fra) as part of this tutorial. The screen capture also shows the connection to the Classic infrastructure (this is optional).

  

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• A DNS with IBM Cloud DNS Services (in Classic infrastructure)

  The following screen captures show the domain registered with IBM Cloud DNS Services (in Classic infrastructure) as part of this tutorial and the related zone information.

  

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Setup

Refer to the Deploy Red Hat OpenShift Container Platform on IBM Power Virtual Server using user-provisioned infrastructure installation guide for deploying OpenShift.

When running the installation helper script by following the mentioned guide, you will be presented with the option to use IBM Cloud DNS Services (in classic infrastructure) and the VPC application load balancer as shown:

• For using IBM Cloud DNS Services, enter yes for the following prompt:
  Do you want to use IBM Cloud Classic DNS and VPC Load Balancer services?
• Specify IBM Cloud VPC name for the following prompt:
  Enter IBM Cloud VPC name
• Specify IBM Cloud VPC subnet name for the following prompt:
  Enter IBM Cloud VPC subnet name

The installation helper script creates the required VPC application load balancers, configures the front-end listeners and the back-end pools, creates the DNS records, and deploys the OpenShift cluster.

The following screen capture shows the two VPC application load balancers created for the example OpenShift cluster.

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The following screen capture shows some of the CNAME records created by the install helper for the example OpenShift cluster. As you can see, the CNAME records point to the load balancers.

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When using the IBM Cloud Application Load Balancer for VPC, the bastion (helper) node is not used for load balancing.

Additionally, both HTTP and HTTPS ports can be exposed for your application with granular firewall rules when using IBM Cloud Application Load Balancer for VPC with OpenShift. You can also use similar topology to create multi-region cluster for disaster recovery purposes.

Summary

This blog provided an overview of using IBM Cloud Application Load Balancer for VPC and IBM Cloud DNS Services (in Classic infrastructure) for OpenShift cluster deployed in Power Systems Virtual Servers.

After the cluster is up and running, you can try out the tutorials under the Exploring Red Hat OpenShift on Power Systems Virtual Server section of the Learning path: Deploying Red Hat OpenShift Container Platform 4.x on IBM Power Systems Virtual Servers.