Expertise level: Advanced
Booting into single user mode is a procedure usually reserved for emergency situations such as when the root password has been lost. This procedure is for Classic Linux servers. To reset the root password on a Smart Server, please open a technical ticket.
Note that when booting a remote server into single user mode, a KVM/IP is absolutely required. To order a KVM/IP, please view our Knowledge Base article.
After you have received your KVM/IP accesses by email, log into the KVM/IP interface. A window will come up that will display the video output of your server.
Reboot your server by clicking on the "Ctrl-Alt-Del" key.
Wait for the reboot to finish processing. When the server has physically rebooted and completed its self-test, you will see a GRUB screen. Interrupt it by touching any key. (Your GRUB screen may be different depending on the version installed.)
Select the kernel you want to boot. Usually, the top kernel in the list is the correct one to use. Hit the "E" key to edit the selected entry.
If you are running CentOS, add these terms to the end of the line:
The 'single' term is for booting into single user mode, but 'fastboot' is used to skip certain parts of the booting sequence. This is useful if your system is permanently stuck in a file system check.
If you are running Debian/Ubuntu, add this term to the end of the line:
After making these modifications, hit the "Enter" key to go back to the boot menu, and then use "b" to boot.
The server will boot into single user mode, at which point you can make your desired changes. Please make changes with care; any data lost or deleted can not be restored.