While trying to run a YUM update on a CentOS server today, I got an error message about my /boot partition being full. I ran a df -h and sure enough, there was only 100k left. (My standard install uses 100MB for the boot partition.)

Here’s what I did to fix it.

rpm -q kernel

That returns a list of installed kernel updates. In my case I had more than 25…

kernel-2.6.9-22.EL
kernel-2.6.9-42.0.8.EL
kernel-2.6.9-42.0.8.plus.c4
kernel-2.6.9-42.0.10.plus.c4

kernel-2.6.9-67.plus.c4
kernel-2.6.9-67.0.1.EL
kernel-2.6.9-67.0.1.EL.plus.c4
kernel-2.6.9-67.0.4.plus.c4
kernel-2.6.9-67.0.7.plus.c4
kernel-2.6.9-67.0.15.plus.c4
kernel-2.6.9-67.0.20.EL

To remove some of the older ones, run:

yum remove kernel-2.6.9-42.0.10.plus.c4

or to get several at one time:

yum remove kernel-2.6.9-42.*

I recommend leaving a few of the older ones in case you need to revert one day.