[CentOS] Migrate CentOS 3 to 4 to 5?

Thu Oct 25 08:32:46 UTC 2007
David Christopher Zentgraf <deceze at gmail.com>

Hi,

After the previous debacle with PHP and MySQL it has been decided  
that we think about an upgrade from CentOS 3 to 5, since that would  
solve our problem, if successful. I tried finding information on how  
to best attempt this, but thanks to a plethora of contradictory  
information my head is now spinning with a few rpm (rounds per minute).

The situation is as follows: Remote box at our host who offers CentOS  
3 as the most up-to-date OS, unless you pay them an unholy amount of  
money for RHEL or Windows licences. Popping in a CD for an upgrade  
does not work for us. We can and will have the OS restored to a clean  
post-install state prior to updating. I have little intimate  
knowledge with CentOS, RPMs or yum, but general good UNIX experience.  
I know "live" yum migrations are greatly discouraged, but it seems to  
work for people.

The most detailed instructions I seemed to be able to find are here:  
http://www.centos.org/modules/newbb/viewtopic.php?topic_id=382
Can anybody confirm this to work, is there anything else that's  
implied but not spelled out?
Another, differing approach seems to be this: http:// 
levine.sscnet.ucla.edu/general/software/tc1000/rmredhat.htm
Any ideas about it?

Any hints, or rather detailed steps, would be greatly appreciated.
Chrs,
Dav