[CentOS] Upgrading FC2 to CentOS 5.* - anyone second this?

Thu May 31 20:22:25 UTC 2012
Lamar Owen <lowen at pari.edu>

On Wednesday, May 30, 2012 02:56:24 PM Max Pyziur wrote:
> My hope is to upgrade; that way I don't have to change/specify partition
> topology, and hopefully only minimally adjust the existing configurations.

I have tried this type of upgrade before; I have not had it go well for the most part.  The only way I'd try to do an FC2 to C5 upgrade is by incrementally upgrading up to FC4 or FC5 using install media, then boot the C5.8 install media with 'upgradeany'.  It may break things very badly.

I have had to do this sort of upgrade on SPARC systems running Aurora SPARC Linux; did a yum-based upgrade up through a few revs, and it was a pain.  I only did it because install media wasn't already available, and you had to go backrev to get booting media on my particular box (although the installed system worked fine once installed).  It is really something I would rather not do without the preupgrade logic in place, primarily because of non-repo or third-party repo packages that may or may not be around any more on a newer repo; for that matter, the Fedora package set in the FC2 days is likely to be larger than the C5 package set unless you enable third party repos at install/upgrade time, and that isn't guaranteed to work.

This sort of discussion is in the archives several times, and I think I have put my particular recipe out there before.  It is recommended by the upstream vendor, Red Hat, to not do any major version upgrades from one version of EL to another.  EL4 was based from around FC3, and you are essentially talking about a direct upgrade from a pre-EL4 to EL5; these two are more different than you might think. (see https://en.wikipedia.org/wiki/Red_Hat_Enterprise_Linux#Relationship_to_free_and_community_distributions for info)

Beyond that, the upgradeany path is probably the least tested of all the anaconda install paths, and will likely traceback at the worst possible time.  Upgrades aren't easy (even on Debian/Ubuntu where packages being upgraded can ask questions and do significant things, unlike in the RPM scriptlet case).  Preupgrade has failed for me more than it has worked, going through several revs of Fedora.

Having said all of that, if you analyze your particular package set and you figure out that all of the packages have identical configs between FC2 (or EL4, for that matter) and EL5, and that you're not using a package that has had major changes and upgrades break data (like PostgreSQL; FC2 shipped a significantly older PostgreSQL than CentOS 5 does, and a major version upgrade on PostgreSQL requires some special handling), you might be able to get it to work.

But it will probably take more time to successfully upgrade than it will to do a fresh install with the same list of packages and a restore of compatible configurations onto that fresh install.  But, it's your time to waste if you want to do so.

If you want to see this sort of thing on the MS OS, there is a YouTube video out there highlighting upgrading through all versions of Windows; the cruft leftover from Window 1.0, 2.0, and 3.x in a Windows 7 upgraded system is a thing to behold.