Yum and kernels, removing old one’s and limiting how many kernels yum keeps around

Check installed kernels:
# rpm -q kernel
kernel-2.6.32-279.el6.x86_64
kernel-2.6.32-279.2.1.el6.x86_64
kernel-2.6.32-279.5.2.el6.x86_64
kernel-2.6.32-279.9.1.el6.x86_64

Remove old kernels:
# package-cleanup –oldkernels –count=2

Make it permanent:
#vi etc/yum.conf
installonly_limit=2