- What is kernel
- How to update kernel
- Setting up default kernel
- How to remove unusable kernel
What is Linux kernel?
Linux kernel is an free & opensource monolithic Unix-like computer operating system. Kernel is a core of any operating system, without kernel any operating system can not work. For example kernel is a heart and it act as a brain like human body. It is invented by Linus Torvalds in 1991 at Helsinki university.
How to update kernel in redhat & centos.
Here you can download the latest kernel version:-
First of all you have to download the kernel then with the help of rpm you can install the kernel in your RPM based operating system.
By default kernel version in Redhat Linux 7.3 is 3.10.0-514.el7.x86_64
[[email protected] ~]# uname -a
[[email protected] ~]# rpm -ivh kernel-lt-4.4.155-1.el7.elrepo.x86_64.rpm
First command will check the installed linux kernel version in the Linux operating system. Another command will install the kernel in your Linux operating system, make sure you are in the location where you downloaded your kernel.
As we can see in figure we have three lines, By default it contain two line but now it has three lines because we have successfully updated the linux kernel.
Setting default kernel:-
You can set default kernel at the time of booting as well as you can manage the booting time by changing in /boot/grub2/grub.cfg configuration file.
By default new kernel set as a default kernel or first command also set new updated kernel as a default kernel and second command will set previous kernel as a default kernel.
[[email protected] ~]# grub2-set-default 0
[[email protected] ~]# grub2-set-default 1
How to remove unusable kernel using yum
[[email protected] ~]# yum remove kernel-lt-4.4.155-1.el7.elrepo.x86_64.rpm
This command will remove the kernel version which you want to remove as we can see in figure.