How to boot a system into rescue mode

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux 10
  • 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
  • Red Hat Enterprise Linux 4
  • Rescue mode
    • note: in RHEL 7/8, rescue mode is referred to as "Anaconda Rescue Mode" to differentiate it from the vmlinuz-0-rescue-* rescue image.

Issue

  • Having trouble booting my system, how do I get into rescue mode during boot time?

Resolution

System Admin/Installation Guide instructions:

To boot the system into rescue mode please use following steps:

  1. Boot from ISO

Boot the system from the relevant Binary DVD or boot disc of the same major release as the system. The ISO9660 disc images are available as follows:

  1. Enter rescue mode

Once the system has successfully booted from the ISO image, the Red Hat Enterprise Linux install menu will appear.

  • Red Hat Enterprise Linux 7/8/9/10:

    Select 'Troubleshooting/Rescue a Red Hat Enterprise Linux system' at the install menu or append the inst.rescue option to the boot command line.

  • Red Hat Enterprise Linux 6:

    Select 'Rescue installed system' at the install menu or type 'linux rescue' at the 'boot:' prompt.

  • Red Hat Enterprise Linux 4/5:

    Type 'linux rescue' (without the quotes) at the 'boot:' prompt and hit Enter.

      [F1-Main] [F2-Options] [F3-General] [F4-Kernel] [F5-Rescue]
  boot: linux rescue
  1. Configure rescue options (Red Hat Enterprise Linux 4/5/6)
  • Configure language and keyboard
  • Configure networking.
  1. Mount filesystems (if desired)

  • A 'Rescue' screen will appear telling you that the program will now attempt to find an existing Red Hat Enterprise Linux installation to mount on /mnt/sysimage in Read & Write mode in RHEL7 and /mnt/sysroot/ in RHEL8/9. Select 'Continue' on this screen or 'Skip/Skip to shell' if you do not wish to mount filesystems.

    If you choose to mount filesystems, a confirmation message will appear that the system has been mounted.

    • RHEL 5 and later: Press <return> or Enter to get a shell.
    • RHEL 4 immediately drops to a shell.

    If you choose not to mount filesystems you will immediately be dropped to a shell.

After entering rescue mode

  • The rescue shell

    This shell exists in the installation/rescue environment, with the installed system optionally mounted under /mnt/sysimage. This shell has a number of tools available for rescuing a system, such as all common file system, disk, LVM, and networking tools. The various bin directories of the target system are added to the default executable search path (${PATH}) as well.

  • Check that filesystems have been mounted (if desired)

    At the shell prompt, run df to see if the dev, sys, proc filesystems are mounted under /mnt/sysimage. If these directories are not mounted, you can try to mount them manually as follows:

      # mount -o bind /dev /mnt/sysimage/dev
  # mount -o bind /sys /mnt/sysimage/sys
  # mount -t proc /proc /mnt/sysimage/proc
  # mount -o bind /dev/shm /mnt/sysimage/dev/shm

  • chroot (if desired)

    To chroot to the existing system root:

      # chroot /mnt/sysimage

  • To exit from the chroot environment:

      # exit

    After exiting from chroot environment, the system can be rebooted by executing exit command again:

      # exit

  • Resources
    Red Hat Enterprise Linux Rescue Options

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