- Connect a terminal to the BIG-IP serial console port.
- Restart the BIG-IP system.While starting, the BIG-IP system displays the GRUB menu and counts down before continuing the start process.
- Before the countdown expires, use the arrow keys to stop the countdown and select the appropriate boot image.Note: Alternately, press SHIFT+6 (^) to move up and the V key to move down.
- Press the E key to edit the start options.A new GRUB menu displays.
- Press the arrow keys to select the line that begins with kernel /boot/<boot location>/vmlinuz.
- Press End or the Right arrow to go to the end of line.
- Type the word rd.break at the end of the kernel /boot/<boot location>/vmlinuz line.Depending on the platform, the boot command may appear similar to the following example:
kernel /boot/1/vmlinuz ro root=UUID=7237fa64-e347-4bb7-a755-6e2617bd7c0e console=ttyS0 panic=1 platform=D113 <default_cpu_order quiet> rd.break
If the boot command in the edit mode appears with default_cpu_order quiet, you simply add rd.break after space.
NOTE: if there is no space before rd.break, it will not boot into single-user mode.To save the change, press Enter key
IMPORTANT: When starting BIG-IP Virtual Edition in single user mode, you should additionally delete the console=ttyS0 line, leaving only console=tty0. If you skip this, the BIG-IP VE starts and the login prompt does not display on the console.
Note: When starting in single-user mode, the BIG-IP system may attempt to perform a file system check (fsck) and request the root password. If the root password is unknown, you may be able to skip the file system check by appending rd.break fsck.mode=skip instead of rd.break. You should not use fastboot because it does not work in CentOS 7, the base operating system.
- On grub menu, while kernel /boot/1/vmlinuz… is selected, press ‘b‘ to boot into single-user mode.After the starting sequence completes, a command-line prompt displays. You have started the system in single-user mode, and must have following prompt
switch_root:/#NOTE: If “Give root password for maintenance” is prompted, then it is NOT in single-user mode. Must missed something above procedure. So try to follow above again.
- When you are finished using single-user mode, enter exit or reboot to return the BIG-IP system to normal operating mode.
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