Kernel Clean

Keep GRUB default kernel up to date, and prune installed kernels on CentOS 7.

Description

This script checks what kernels you have installed on your system. If you have more than five, it will prompt to remove the oldest kernels. It also checks what the currently running kernel is, and which one will become active on next boot (current and default). If the default kernel is not the newest, you will be prompted about whether or not to set the newest kernel as default for future boots.

Getting Started

• Clone the repository.

• Install the Perl module Sort::Versions to system Perl.

yum install perl-Sort-Versions

• Copy bin/kerclean into a location in your $PATH. I prefer ~/bin/. Assuming the repository has been cloned to ~/repos/kernel-clean/ and that ~/bin/ is in your $PATH:

cp ~/repos/kernel-clean/bin/kerclean ~/bin/kerclean

• Or instead of copying into a location in your path (and having to remember to do so when versions update), use a symlink.

ln -s ~/repos/kernel-clean/bin/kerclean ~/bin/kerclean

• To run:

$ kerclean

If you are not root, you will be prompted to run as sudo.

The script will always prompt before making changes. Additionally, it is always safe to run, even if there are no changes to make. Therefore, it can be used as a utility to simply list what kernels are installed, which is active for your current session, and which will be active on next boot.

Example run

$ bin/kerclean
[sudo] password for userfoo:
4 kernels found:
        (0) 3.10.0-957.10.1.el7.x86_64
(c) (d) (1) 5.0.2-1.el7.elrepo.x86_64
        (2) 5.0.1-1.el7.elrepo.x86_64
        (3) 3.10.0-957.5.1.el7.x86_64

[  (c) Currently active kernel.    (d) Default grub kernel.  ]

Had the newest kernel not been the same as the default (d) kernel, the user would have been prompted to change the GRUB setting. Had there been more than five kernels, the user would have been prompted to remove old kernels.