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IMPORTANT NOTE: This site is not official Red Hat documentation and is provided for informational purposes only. These guides may be experimental, proof of concept, or early adoption. Officially supported documentation is available at docs.openshift.com and access.redhat.com.

Creating a ROSA cluster in STS mode

Paul Czarkowski

Last updated 05/31/2022

Tip The official documentation for installing a ROSA cluster in STS mode can be found here.

Quick Introduction by Ryan Niksch (AWS) and Shaozen Ding (Red Hat) on YouTube

STS allows us to deploy ROSA without needing a ROSA admin account, instead it uses roles and policies with Amazon STS (secure token service) to gain access to the AWS resources needed to install and operate the cluster.

This is a summary of the official docs that can be used as a line by line install guide and later used as a basis for automation in your favorite automation tool.

Note that some commands (OIDC for STS) will be hard coded to US-EAST-1, do not be tempted to change these to use $REGION instead or you will fail installation.

Prerequisites

Prepare local environment

  1. set some environment variables

     export VERSION=4.10.15 \
            ROSA_CLUSTER_NAME=mycluster \
            AWS_ACCOUNT_ID=`aws sts get-caller-identity --query Account --output text` \
            REGION=us-east-2 \
            AWS_PAGER=""
    

Prepare AWS and Red Hat accounts

  1. If this is your first time deploying ROSA you need to do some preparation as described here. Stop just before running rosa init we don’t need to do that for STS mode.

  2. If this is a brand new AWS account that has never had a AWS Load Balancer installed in it, you should run the following

     aws iam create-service-linked-role --aws-service-name \
     "elasticloadbalancing.amazonaws.com"
    
  3. Associate your AWS account

    To perform ROSA cluster provisioning tasks, you must create ocm-role and user-role IAM resources in your AWS account and link them to your Red Hat organization.


    OCM Role
    The first role you will create is the ocm-role which the OpenShift Cluster Manager will use to be able to administer and Create ROSA clusters.

    If you haven’t already created the ocm-role, you can create and link the role with one command.

    rosa create ocm-role
    

    Tip If you have multiple AWS accounts that you want to associate with your Red Hat Organization, you can use the --profile option to specify the AWS profile you would like to associate.

    If you have already created the ocm-role, you can just link the ocm-role to your Red Hat organization.

    rosa link ocm-user --role-arm <arn>
    

    Tip You can get your OCM role arn from AWS IAM:

    aws iam list-roles | grep OCM
    


    User Role
    The second is the user-role that allows OCM to verify that users creating a cluster have access to the current AWS account.

    If you haven’t already created the user-role, you can create and link the role with one command.

    rosa create user-role
    

    Tip If you have multiple AWS accounts that you want to associate with your Red Hat Organization, you can use the --profile option to specify the AWS profile you would like to associate.


    If you have already created the user-role, you can just link the user-role to your Red Hat organization.

    rosa link user-role --role-arn <arn>
    

    Tip You can get your User role arn from the ROSA cli: rosa whoami

    look for the AWS ARN: field

Deploy ROSA cluster

  1. Make you your ROSA CLI version is correct (v1.2.2 or higher)

     rosa version
    
  2. Run the rosa cli to create your cluster

    You can run the command as provided in the ouput of the previous step to deploy in interactive mode.

    Add any other arguments to this command to suit your cluster. for example --private-link and --subnet-ids=subnet-12345678,subnet-87654321.

     rosa create cluster --sts --cluster-name ${ROSA_CLUSTER_NAME} \
       --region ${REGION} --version ${VERSION} --mode auto -y
    
  3. Validate The cluster is now installing

    The State should have moved beyond pending and show installing or ready.

     watch "rosa describe cluster -c $ROSA_CLUSTER_NAME"
    
  4. Watch the install logs

     rosa logs install -c $ROSA_CLUSTER_NAME --watch --tail 10
    

Validate the cluster

Once the cluster has finished installing we can validate we can access it

  1. Create an Admin user

     rosa create admin -c $ROSA_CLUSTER_NAME
    
  2. Wait a few moments and run the oc login command it provides.

Cleanup

  1. Delete the ROSA cluster

     rosa delete cluster -c $ROSA_CLUSTER_NAME
    
  2. Clean up the STS roles

Once the cluster is deleted we can delete the STS roles.

> Note you can get the correct commands with the ID filled in from the output of the previous step.

```bash
rosa delete operator-roles -c <id> --yes --mode auto
rosa delete oidc-provider -c <id>  --yes --mode auto
```