Upgrade vs Reinstall

I'm a generalist SysAdmin. I use Linux when necessary or convenient. I find that when I need to upgrade a specific solution it's often easier to just spin up an entirely new instance and start from scratch. Is this normal or am I doing it wrong? For instance, this morning I'm looking at a Linux VM whose only task is to run Acme.sh to update an SSL cert. I'm currently upgrading the release. When this is done I'll need to upgrade acme.sh. I expect some kind of failure that will require several hours to troubleshoot, at which point I'll give up and start from scratch. I'm wondering if this is my ignorance of Linux or common practice?

Toribor ,
@Toribor@corndog.social avatar

I'm a sysadmin as well and I consider spinning up a new instance and rebuilding a system from scratch to be an essential part of the backup and recovery process.

Upgrades are fine, but they can sometimes be risky and over a long enough period of time your system is likely accumulating many changes that are not documented and it can be difficult to know exactly which settings or customizations are important to running your applications. VM snapshots are great but they aren't always portable and they don't solve the problem of accumulating undocumented changes over time.

Instead if you can reinstall an OS, copy data, apply a config and get things working again then you know exactly what configuration is necessary and when something breaks you can more easily get back to a healthy state.

Generally these days I use a preseed file for my Linux installs to partition disks, install essential packages, add users and set ssh keys. Then I use Ansible playbooks to deploy a config and install/start applications. If I ever break something that takes longer than 20 minutes to fix I can just reinstall the whole OS and be back up and running, no problem.

kevincox ,
@kevincox@lemmy.ml avatar

I think yes. In general if you have good setup instructions (preferably automated) then it will be easier to start from scratch. This is because when starting from scratch you need to worry about the new setup. But when upgrading you need to worry about the new setup as well as any cruft that has been carried over from the previous setup. Basically starting clean has some advantages.

However it is important to make sure that you can go back to the old working state if required. Either via backups or leaving the old machine around working until the new one has been proven to be operational.

I also really like NixOS for this reason. It means that you can upgrade your system with very little cruft carrying over. Basically it behaves like a clean install every update. But it is easier to roll back if you need to.

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