How to boot RHEL 7 and CentOS 7 into Rescue Mode

Booting RHEL 7 and CentOS 7 into Rescue Mode

Step 1 – At the Grub2 boot menu type e to edit the grub config.

Note: Depending on you environment you may have to type p first and enter a grub password before having the permissions to edit the grub config.

Step 2 – Locate the first line that beings with linux16. Use the END Key or the arrow keys to go to the end of that line. I my example the end of the line is right after LANG=en_US.UTF-8.

linux16 /vmlinuz-3.10.0-693.2.2.el7.x86_64 root=/dev/mapper/sysvg-root ro crashkernel=auto rd.lvm.lv=sysvg/root rd.lvm.lv=sysvg/swap rhgb quiet LANG=en_US.UTF-8

Step 3 – At the end of the line append systemd.unit=rescue.target. the entry should resemble the line below.

linux16 /vmlinuz-3.10.0-693.2.2.el7.x86_64 root=/dev/mapper/sysvg-root ro crashkernel=auto rd.lvm.lv=sysvg/root rd.lvm.lv=sysvg/swap rhgb quiet LANG=en_US.UTF-8 systemd.unit=rescue.target

Step 4 – After you have entered systemd.unit=rescue.target press CRTL+X to boot your system into rescue mode.

By this simple process you can boot RHEL 7 and CentOS 7 in Rescue Mode