Clean unuse kernel

1. Intro

If you have an old kernel that you are not using, you should delete it.
Because it fill up the /boot capacity.

2. How to do?

2.1. check kernel & check disk usage

# current kernel
uname -a

# list kernel
rpm -q kernel
cat /etc/grub.conf | grep title

# disk usage
df -h

2.2. Install yum-utils

rpm -qa yum-utils
yum install yum-utils

2.3. Delete old kernel

package-cleanup --oldkernels --count=2

Old Kernel Options:
--oldkernels Remove old kernel and kernel-devel packages
--count=KERNELCOUNT
  Number of kernel packages to keep on the system (default 2)
--keepdevel Do not remove kernel-devel packages when removing kernels

2.4. check kernel & check disk usage

# current kernel
uname -a

# list kernel
rpm -q kernel
cat /etc/grub.conf | grep title

# disk usage
df -h

2.5. Delete old kernels automatically

vi /etc/yum.conf ; modify
    installonly_limit=2