upgrade centos 8 to almalinux | hereditary task

[Tanker]

Hello, I just got a new/old project, "the other guy just quit"...
So, I was looking at what I got on this dedicated server and I noticed that it still running CentOS 8, I've read the documentation regarding the upgrade, but I'm not 100% sure about the configuration.
So after the upgrade do I have to reconfigure everything? or, is this like a plug & play, I just want to be sure how the upgrade works since this is a live production server with lots of APPs running.
This server has a few domains, lots of sub-domains, API, redis, nodeJS, github and the main "controller" WHM/cPanel., I wanna be prepared with some downtime while upgrading or re-configuring the WHM/cPanel.
Plus since this is a remote server if something goes wrong I have to open a "ticket" (I already requested the VPN credentials but it might take some time since no one knows who has the contact information...) for them to restore the server and it might take some time for them to do so, I don't wanna say that it might take 10 to 15min when in fact it may take all day.

I just wanna be ready, I hope that some one has already done it on a production server and be able to share their experience.

Thank you.

 

[andrew.n]

It's like plug and play yes. All accounts and settings remain the same, only the system files will be replaced. I have done a couple of upgrade from CentOS 8 over to AlmaLinux 8 and all went fine so it is a relatively safe upgrade especially since the binaries are the same they will be just reinstalled from a different repo. You should count with about 30 minutes for the upgrade itself.

On the other side, especially since it's a production server, take full backups beforehand so if there is any problems you can revert back. You can read more about the script here:

How to Convert from CentOS 8 to AlmaLinux OS 8 | cPanel & WHM Documentation

This document provides instructions for migrating a WHM server from CentOS 8 to AlmaLinux OS 8.

docs.cpanel.net

 

[cPRex]

While we normally don't support upgrades like this, CentOS 8 to AlmaLinux 8 is the one upgrade that is officially supported through the guide that @andrew.n linked. It should serve you well, but please take backups like he advised and let us know if you run into issues.

 

[Tanker]

Thank you very much, I feel more confident now.
keep the post open so that I can share the aftermath...

Again, thank you.

 

[Tanker]

Hello guys,
Sorry it toke me a little longer than I expected, we had to re-schedule the upgrade.
Out all things there was only one thing that needed to be update as stated at the gitlab.
The mirrorlist has been offline since Jan 31, 2022, so to make the upgrade we need to update the mirrorlist first:
Either one by one line or by a single command line...
I did line by line for the mirror list, then the update...
After that I had a few errors with the gitlab key not being authorized, not sure what it was talking about so I removed that library...
then # bash almalinux-deploy.sh after that everything went ok!


Thank you all!