/bootpartition and you run into an issue with low disk space, removing unused kernels will provide a remedy.
Check for current Kernel
First, check what kernel is currently used by your server:
# uname -a Linux localhost.localdomain 3.10.0-693.5.2.el7.x86_64 #1 SMP Fri Oct 20 20:32:50 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
List all installed kernels
In this step we will list all currently installed kernels:
# rpm -q kernel kernel-3.10.0-327.36.3.el7.x86_64 kernel-3.10.0-514.2.2.el7.x86_64 kernel-3.10.0-693.5.2.el7.x86_64
kernel-3.10.0-693.5.2.el7.x86_64 is currently loaded and used. based on the about output this is the latest version.
Remove old kernels manually
At this stage we can use
yum command to manually remove unused Linux kernels:
Remove old unused kernel automatically
package-cleanup command which is a part of
yum-utilspackage we can uninstall any number of old kernels automatically. As an example using
--oldkernels --count=2option with
package-cleanup command the command will remove all unused kernel while keeping last three most recent kernel versions installed.
Let’s remove all kernels expect the latest currently loaded kernel:
Configure yum to auto-remove old kernels
By default, CentOS will keep last 5 kernels installed on your system. This behavior is defined by
installonly_limit=5 line within
/etc/yum.conffile. Update the
/etc/yum.conf configuration file appropriately to keep desired number of old kernels on your system after update. The minimum value to be set is
2. Example of the
/etc/yum.confconfiguration file to keep only last two kernel versions: