The_IT_Guy

Kernel upgrade is a simple and smooth process. However, there are a few cases for which all ways need a fallback kernel available. NOTE:  Test changes first in using #1 before making the permanent changes to the system.  Temporary:  Boot into the previous version of Kernel: Interrupting the boot process using ESC key keep will splash the available kernel version on the system. Select the kernel.  2) Permanent  Method 1: sudo view /boot/grub/grub.cfg and copy the full name of your old kernel. sudo vi /etc/default/grub and, at the top, change GRUB_DEFAULT=0 to instead read GRUB_DEFAULT=your_kernel_name_from_grub.cfg , and save the change (you may like to keep a copy of the original file for safety). sudo update-grub Method 2:        1. grep -A100 submenu  /boot/grub/grub.cfg |grep menuentry       2. update  GRUB_DEFAULT=gnulinux-advanced-version>gnukernl-kernel-version in /etc/default/grub     ...

The kernel is the heart of the system which converts the human-readable language to machine-understandable language  Steps: 1) Identify the current version of kernel 2) Update the repository 3) Install kernel   Identify the current version of kernel: uname is used to check the kernel of a machine #uname -a Linux hostname 4.4.0-186-generic #216-Ubuntu SMP Wed Jul 1 05:34:05 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux # uname -sr Linux 4.4.0-186-generic Update the repository:  apt-get update apt-get remove Install Kernel: apt-get install --install-recommends linux-generic-{version} linux-headers-{version} linux-modules-{version} reboot the server #reboot -f  verify the current kernel using # uname -sr   Once verified we can remove the old kernel version to list all the old kernels use  dpkg -l|grep linux-image* apt-get remove --purge linux-image-{older-kernel-version} Note: It is always recommended to have at least one alternate kernel to fall back...