The pain of upgrading is rapidly diminishing, thanks to virtualization. That’s the happy story I heard from Paul Cormier, Red Hat vice president of engineering, in a coversation following the Red Hat Enterprise Linux 5 announcement session. You can just pack that RHEL4 ecosystem in a suitcase and carry it on over to RHEL5.
Cormier explained that moving up to a new release has been a hassle because the ecosystem has to move with the operating system. That means, for instance, that all your apps have to be certified on that new OS. Said Cormier:
“Virtualization splits that so that now they can move independently without waiting for ISVs to get ready. So this is really a big deal. You can go to RHEL5 and pick up all the storage capabilities, etc., and if your ISV isn’t ready with a RHEL5 certification, then just run RHEL5 with a RHEL4 guest. That was always a big issue with us with our OEM partners when we make that big change. Now we can separate the guest.”
You can do your migration in pieces, running apps on either RHEL4 or RHEL5 in guest OSes on virtual machines.
“If you can run a RHEL4 guest it will be an easy migration,” said Cormier. “While you’re migrating, if you still want to run on RHEL4 and test everything on RHEL5 on a guest OS, you can. The possibilities are unlimited, thanks to virtualization.”
This sounds super, just as long as you can track what RHEL4 app or RHEL5 app is running on which VM and what’s in production and what’s not. But that’s another story…