We have around 100 AWS EC2 instances running on RHEL 7.9. I am not sure the best way to upgrade to 8+ I'm not a Unix admin. What is the recommended approach as many of our legacy applications (dev, test, uat, stage environments) are deployed to these servers including production? Any recommendations would be greatly appreciated.
This is going to sound crass and dismissive, but it's really not. I mean this with sincerity and with your best interests at heart.
Hire a qualified professional.
You can also lean on RHEL's professional support. With that many instances, you should have a support contract with RH.
This but if you want to try it yourself make a back up first and then you can follow the official documentation but it's not supported for all configurations.
Upgrading from RHEL 7 to RHEL 8 Red Hat Enterprise Linux 8 | Red Hat Customer Portal
This document provides instructions on how to perform an in-place upgrade from Red Hat Enterprise Linux 7 to Red Hat Enterprise Linux 8 using the Leapp utility. During the in-place upgrade, the existing RHEL 7 operating system is replaced by a RHEL 8 version.
We can't hire any pro. All I need is to figure out an in-place upgrade on just 1 instance. I can follow the same process for the rest. It looks like a fairly straightforward forward as I already use v7.9 Thanks.
Then you can follow the directions linked above. The process is simple enough until things break.
I'd copy an instance, back it up, and try the upgrade.
