[Centos] Upgrading from 3.4 to 4.0 beta X

[Jonathan Dill]

Johnny Hughes wrote:

>On Fri, 2005-01-21 at 23:58 -0800, Michael Taylor wrote:
>  
>
>>Please forgive me if I missed something, but I've searched all over in
>>hopes of finding something documented on a procedure to upgrade a
>>Centos 3.4 system to the beta.  I've got the DVD burned and am testing
>>the process on VMWare.  All I could figure out how to do was install
>>over the existing partition without formatting, but this was quasi-
>>disastrous so I 'reverted' my VMWare drive to the prior state.  Is
>>there some way to reconfigure yum.conf, GPG keys, etc. so that it will
>>pull down the changes?  Or, is there a way to 'upgrade' the system
>>using the CD as a source?  Any help would be appreciated.  I was
>>hoping it was as simple as the upgrade from 3.3 to 3.4, but I couldn't
>>find anything out there.
>>    
>>
My 2c is that you'll spend so much time trying to figure out how to do 
it--or having to fix things that don't work right later--that it would 
have taken less time to have just done a fresh install of the new OS and 
set up everything you had on the old version.  You might try mkkickstart 
if you just want to get the same set of packages, it seems to work for 
some people but I haven't had much luck with it.  Usually, I just make a 
list of packages on the old and new "machine" and compare and install 
packages until I have basically the same set of packages installed, 
something like:

rpm -q -a \
| awk '{n=split($0,a,"-"); delete a[n]; delete a[n-1]; for (j in a) 
printf "%s-",a[j]; printf "\n"}' \
| sort -u > old.txt

Do the same to make new.txt on the new machine, then

comm -23 old.txt new.txt | awk '{print substr($0,1,length($0)-1)}' > 
want.txt

If you just want to get user files, since it's a VM, usually I set up 
/home as a separate virtual disk, then you can just make a new VM and 
use the old disk file for /home with the new VM.  You can even put the 
virtual disk for the old "/" as an extra disk and mount it as say /r2 or 
/old to copy over settings from /etc and so on.  If you want /usr/local 
or /opt or whatever, just rsync it from the old root.

--jonathan