On 07/25/2013 01:28 AM, David G.Miller wrote:
The problem of upgrading from FC-n to FC-n+1 is basically the same as upgrading EL-n to EL-n+1.
No; upgrading ELx to ELx+1 is like upgrading Fn to Fn+k(x), where k(x) is an element of an array of integer constants; x is the starting EL release, so k(3)=3 [RHEL3 was based on what I'm going to call 'Fedora Core 0,' which was the pre-fedora RHL 10 beta; see footnote 1]; k(4)=3, k(5)=6 (or 7, since some F13 packages showed up in EL6), and k(6) will probably be 7 or so.
Doing this without going stepwise through the Fedora releases is a challenge. I forget how large of an increment preupgrade can do, but I remember doing it F12 to F13 to F14, and it had issues even going Fn to Fn+1, especially if any part of the massive yum transaction fails for any reason (it leaves the system with a half completed yum transaction that yum-complete-transaction simply won't deal with, and then you have to finish the upgrade manually and manually remove the older packages).... I have done this twice on two separate machines, one had issues going from F12 to F13 and the other one had issues going from F13 to F14. The Fn to Fn+1 upgrade path is somewhat expected to work; Fn to Fn+2 probably won't work correctly, especially if major changes are in both releases.
To get an EL5 system up to EL6 stepwise with yum, the only semi-sane way would be to upgrade EL5 (FC6 or so based) to F7, then to F8, then to F9, then to F10, then to F11, then to F12, and you might maybe possibly be able to get F12 up to EL6 reasonably easily. That's a k(5) of 6; EL6 to EL7 may be a bit harder, with a k(6) of 7 (assuming EL7 really does get based off of F19).
This of course goes through the KDE 3.5 to KDE 4.3 upgrade, so there's a very big difference if you're a KDE user.....
Having said that, back in the days when I was a user of Aurora SPARC Linux on some Sun Ultra hardware, yum upgrades were the norm, since install media wasn't spun for every release. And it was not a single, simple yum transaction; certain packages had to be upgraded before others, and some had to be parachuted in with rpm. And some things were, well, pretty difficult to deal with on a couple of the increments.
In the Ubuntu world, this is like taking Ubuntu LTS 6.06 straight to 8.04, or worse. I've done the 6.06 to 8.04 thing, by the way, and have no desire to repeat it.
In the Windows world.... well, there's actually several Youtube videos of that, and it's hilarious what had to be done to get a Windows 1.0 install upgraded through every step to Windows 7 and 8. And the artifacts left behind..... [2][3]
Upgrades are hard to do properly, especially in a non-engineered system like a Linux distribution (I know, I know, upstream has engineers working on it and doing integration, but as long as there are packages whose own upstream is outside of TUV's control, it's not an engineered distribution in the strict sense.....). (What I want is the 'Redneck' language back for installs........)
I wouldn't want to guarantee that an arbitrarily complex installation will work though and the people who really want to upgrade are those with really complex systems that they don't want to have to re-create from a clean installation.
Heh. Try doing the upgrade with yum alone from EL4 to EL5 (or EL5 to EL6) on a server with an active PostgreSQL database. For that matter, try using the unsupported 'upgradeany' anaconda boot argument and watch your working database go bye-bye.
[1] https://en.wikipedia.org/wiki/Red_Hat_Enterprise_Linux#Relationship_to_free_and_community_distributions [2] https://www.youtube.com/watch?v=eY-UHdswFkg (note the length! and goes to 8) [3] http://rasteri.blogspot.com/2011/03/chain-of-fools-upgrading-through-every.html (note that the video is somewhat NSFW due to some text that is entered.....)
