[Cialug] A word to the wise

[Tom Pohl]

Tonight, I learned an important lesson about redhat type boxes and yum!

Yum apparently uses /etc/redhat-release to tell what version and  
flavor distro you are using.  If you change /etc/redhat-release to  
reflect a certain "compatible" version of a different redhat  
operating system (say redhat-4 instead of fedora core 5 (or even 6)),  
make sure you change it BACK before next running yum update.

One of my fedora based development boxes needed redhat-release to be  
set to redhat-4 in order for oracle's installer to be happy and I of  
course never changed it back to the original name after the install  
was complete.  Tonight, I yum updated the box and remotely rebooted  
the box.   It never cam back :)  It had installed the redhat-4  
version of the 2.6.20 kernel and was very grumpy about finding my  
filesystems.  Luckily, you can always boot back to your previous  
kernel, where I quickly realized my mistake (grub.conf listed  
redhat-4 in the title of the new kernel instead of Fedora).

The important part, was once I fixed redhat-release, I needed to use  
rpm -e to remove the specific version of the rh4 rpm since it had a  
newer version number than my fedora release (it was a fedora 5 box ->  
redhat-4 screwup) and yum wouldn't update the kernel because it  
didn't "need" to be updated. Then you can successfully yum update to  
get the correct kernel and boot happily once again.

This concludes our current lesson on how NOT to update your box :)

-Tom