Here is how to fix the following error when upgrading the kernel
When there is not enough space on your boot drive for the kernel upgrade, you will get an error message similar to this:
Transaction Check Error:
installing package kernel-2.6.32-279.5.2.el6.x86_64 needs 14MB on the /boot filesystem
At least 14MB more space needed on the /boot filesystem.
.. install failed!
Fixing this is a very easy task, just follow the next few steps
You can check how many kernels you have installed with this command: rpm -q kernel
Make sure you have yum-utils installed by running this command: yum install yum-utils
Then run this command to remove all but 2 of the kernels: package-cleanup --oldkernels --count=2 -y
This will leave you 2 back-up copies and remove the others
To prevent yum from installing more than 2 backups in the future, edit this file using: nano /etc/yum.conf
That is all there is to it, you should now able to upgrade your kernel with: yum upgrade kernel
then reboot by typing: