How to change kernel for boot - Linux

 uname -r ---> will display the version of the Linux kernel currently running on your system.

[root@rac201 ~]# uname -r

5.15.0-101.103.2.1.el8uek.x86_64 ---- default one - we will change Kernel

[root@rac201 ~]#

[root@rac201 ~]#

[root@rac201 ~]# ls -l /boot/vmlinuz-*

-rwxr-xr-x. 1 root root 13484336 Aug 31 09:19 /boot/vmlinuz-0-rescue-acb15413f9ad41d1b3edb1e23d4c616b

-rwxr-xr-x. 1 root root 10843648 May 17  2023 /boot/vmlinuz-4.18.0-477.10.1.el8_8.x86_64

-rwxr-xr-x. 1 root root 13484336 May  2  2023 /boot/vmlinuz-5.15.0-101.103.2.1.el8uek.x86_64

[root@rac201 ~]# grubby --set-default /boot/vmlinuz-4.18.0-477.27.1.el8_8.x86_64

The default is /boot/loader/entries/93eed19701864c2cac4193714f746de8-4.18.0-477.27.1.el8_8.x86_64.conf with index 1 and kernel /boot/vmlinuz-4.18.0-477.27.1.el8_8.x86_64

[root@rac201 ~]# shutdown -Fr now

[root@rac201 ~]# uname -r

4.18.0-477.10.1.el8_8.x86_64