Using local-zones in ROSA Classic

This guide walks through setting up a local-zone in an existing ROSA Classic cluster. Use this approach when you have latency requirements that can be reduced when using a local zone. Since you are not using the default ingress, you will not be able to use the router strategy the cluster has.

Prerequisites

ROSA Classic Cluster with AWS Load Balancer Operator already installed:

• A ROSA classic cluster (BYO VPC) deployed with STS in a region that has local zones.
• Execute the installation step available in the guide: “AWS Load Balancer Operator on ROSA”

Local Zone validations and configuration in your AWS Account:

• Identify the local zone to be used
• Enable the local zone in the account
• The VPC must have enough space to create the Local Zone Subnet. In this example, we create two subnets, one public and one private.

Command line tools used in this guide:

• aws cli
• watch
• nmap

Set up environment

Create environment variables. We assume the CIDR is a valid subnet for the localzone.

AWS Networking Preparation

1. Tag the vpc.

2. Create private and public subnets in the local zone.

3. Associate the new private subnet in the route table.

4. Associate the new public subnet in the route table.

5. Tag the private subnet in the local zone with the cluster infra id.

Cluster Preparation (30 min)

Patch the cluster network operator MTU.

Create and configure ROSA in the localzone

Validate what instance types are available in the configured localzone and set the environment variable with the selected instance type.

Create the machinepool in the localzone and wait until the nodes are available in the list. This could take several minutes.

Label the machinepool so the applications will be installed on the local zone nodes only.

Test.

To test, we create the deployment, applying the match labels, so the pods will run on the local zone nodes.

Validate the deploy is running on a Node in the Local Zone.

Deploy the hello-openshift load balancer in the private subnet in the local zone.

Deploy the hello-openshift load balancer in the public subnet in the local zone. (Optional) NOTE: For perdurable environments, the recommendation is not to expose the cluster directly in the Internet. This step is executed in this guide for testing latency from the internet.

Curl the ALB ingress endpoint to verify the hello-openshift service is accessible.