How do I boot using an alternate / previous / older kernel?

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux 9
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 5

Issue

  • I installed a new kernel with yum and am now experiencing issues, how can I boot into an alternate / previous / older kernel?

Resolution

Temporarily Boot To An Alternative Kernel

  • As the system is booting, you should be presented with a message similar to the following:
Press any key to enter the menu

Booting Red Hat Enterprise Linux (3.10.0-1062.4.1.el7.x86_64) in 3 seconds...
  • At this stage, if you press/send any key, you will be placed into the GNU Grub menu. Here you will be able to use the arrow keys to select and boot into any kernels that are installed on your system. Highlight the previous kernel and press/send Enter to boot using that kernel.
GRUB menu
Example of the GRUB menu

Configure GRUB To Consistently Boot To An Alternative Kernel

Root Cause

  • Running yum update may install a new kernel that will be the new default kernel.

  • Kernels supplied by Red Hat will add an entry automatically to the installed bootloader. It is still possible to boot to a previously installed kernel or modify /etc/grub.conf to specify which kernel to load automatically.

  • To prevent yum update from updating or installing a new kernel, see the following solution:

Diagnostic Steps

  • Check uname output for the current kernel version

  • Check /var/log/yum.log to see if the kernel has recently been updated

  • Check /boot/grub/grub.conf for the default kernel

SBR
Product(s)
Components
Category
Tags

This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.