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This article mainly introduces how to start the Ubuntu 18.04/Debian 9 server in the rescue / emergency mode, the article is very detailed, has a certain reference value, interested friends must read!

Booting the Linux server to single-user mode or rescue mode rescue mode is one of the important troubleshooting methods commonly used by Linux administrators when recovering the server at critical moments. In Ubuntu 18.04 and Debian 9, single-user mode is called rescue mode.

In addition to rescue mode, the Linux server can be started in emergency mode emergency mode, the main difference between them is that emergency mode loads a minimum environment with a read-only root file system file system and does not enable any network or other services. But rescue mode attempts to mount all local file systems and try to start some important services, including the network.

In this article, we will discuss how to start the Ubuntu 18.04 LTS/Debian 9 server in rescue mode and emergency mode.

Start the Ubuntu 18.04 LTS server in single user / rescue mode:

Restart the server and go to the boot loader (Grub) screen and select "Ubuntu". The boot loader page looks like this

Press e, then move to the end of the line that begins with linux and add systemd.unit=rescue.target. Delete the word $vt_handoff if it exists.

Now press Ctrl-x or F10 to start

Now press enter, and you will get shell with all file systems mounted in read-write mode and troubleshoot. After troubleshooting, you can restart the server using the reboot command.

Start the Ubuntu 18.04 LTS server in emergency mode

Restart the server and go to the boot loader page and select "Ubuntu", then press e and move to the end of the line starting with linux, and add systemd.unit=emergency.target.

Now press Ctrl-x or F10 to start in emergency mode and you will get a shell and troubleshoot from there. As we have discussed, in emergency mode, the file system will be mounted in read-only mode, and there will be no network in this mode

Mount the root file system to read-write mode using the following command

# mount-o remount,rw /

Similarly, you can remount the rest of the file system in read-write mode.

Direct Debian 9 to rescue and emergency mode

Restart the Debian 9.x server and go to the grub page to select "Debian GNU/Linux".

Press e and move to the end of the line at the beginning of linux and add systemd.unit=rescue.target to start the system in rescue mode. To start in emergency mode, add systemd.unit=emergency.target.

Rescue mode:

Now press Ctrl-x or F10 to start in rescue mode

Press enter to get shell, and then start troubleshooting from here.

Emergency mode:

Now press ctrl-x or F10 to start the system in emergency mode

Press enter to get shell and use the mount-o remount,rw / command to mount the root file system in read-write mode.

The above is all the contents of the article "how to start the Ubuntu 18.04/Debian 9 server in rescue / emergency mode". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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