No support for RHEL with high availability in-place upgrade

Well, if you know you know, otherwise, you could have wasted the whole evening trying to upgrade RHEL 7.9 with High Availability to RHEL 8.x, and failed!

If you read this post, head to the link at [1] and you’d see that Red Hat does not support i-place upgrades or rolling-upgrades of cluster nodes from one major release of RHEL to another. Here is an extract from [1]:

Red Hat does not support in-place upgrades or rolling-upgrades of cluster nodes from one major release of RHEL to another. For example, there is no supported method for updating some nodes in a cluster from RHEL 6 to RHEL 7, introducing them into the cluster with existing RHEL 6 nodes to take over resources from them, and then updating the remaining RHEL 6 nodes. Upgrades in major releases of RHEL must be done by migrating services from a running cluster on the old release to another cluster running the new release.

Upgrade of systems using High Availability add-on from RHEL 6 to RHEL 7 is unsupported.
Upgrade of systems using High Availability add-on from RHEL 7 to RHEL 8 is unsupported .
Upgrade of systems using High Availability add-on from RHEL 8 to RHEL 9 is unsupported.

I learned this the hard way when I tried to upgrade an EC2 instance running RHEL 7.9 HA. Actually, I did not pay attention about this variant of RHEL 7.9. But now that I know, I want to share this with you.

Here is how to check for the information and confirm whether your instance runs RHEL 7.9 with HA.

❯ aws ec2 describe-instances --instance-id i-05aceeeeeeee4626b \
--query 'Reservations[].Instances[].{InstanceId:InstanceId,ImageId:ImageId}'
[
    {
        "InstanceId": "i-05aceeeeeeee4626b",
        "ImageId": "ami-07fd71119129438ff"
    }
]

Now, let’s check the AMI “ami-07fd71119129438ff”:

❯ aws ec2 describe-images --image-id ami-07fd71119129438ff \
--query 'Images[].{ImageId:ImageId,Name:Name,PLatformDetails:PlatformDetails,Description:Description}'
[
    {
        "ImageId": "ami-07fd71119129438ff",
        "Name": "RHEL_HA-7.9_HVM-20210315-x86_64-2-Hourly2-GP2",
        "PLatformDetails": "Red Hat Enterprise Linux with High Availability",
        "Description": "Provided by Red Hat, Inc."
    }
]

Well, the output above should be clear enough that this particular AMI is RHEL 7.9 with High Availability.

Note that you may need to login with a REd Hat account which can be registered for free on Red Hat Customer Portal.

Reference: