I was playing with the Ubuntu installer expert mode some time ago and all I can say is that it is a gold mine full of pleasant surprises and useful tools. One of those is the remote SSH installation.

The procedure isn't fully automatic and you can't use it to just mail a CD to a friend or a datacenter technician and have him/her pop it in the drive and just boot the machine. The onsite person needs to do some extra work to switch the installer in expert mode, configure and start the network and the SSH server. Only when that is done, you can connect and continue the installation remotely.

(It is possible to create a fully-automated installation CD using preseeding, but we'll cover that in a future post.)

Starting the Installation

Get your installation CD, put it in the drive and boot off it. Hit F6 at the initial screen and select the "Expert mode" option:

Expert mode

Start the installation and you should see the installer main menu. Go ahead and configure the basics like your locale, keyboard, and installation media.

Add the Network Console Installer Component

Now, select the "Load installer components from CD" option and enable the "network-console" package:

Network console installation package

Now, go over the network configuration menu items and configure your network. Either let the machine pick settings from a DHCP server or enter them manually.

Starting the SSH Server

Now, go ahead and select "Continue installation over SSH":

Continue over SSH

The installer will ask you to enter and confirm a password and, when it is done, you will get a summary screen with the connection details:

SSH Details

At that point, the SSH server is fully functional. It is best if you take note of the server key fingerprint, so that you can confirm you are connecting to the correct server.

Connecting via SSH and Finishing the Installation

The SSH summary screen tells it all. Let's do what it asks us to:

~ ssh installer@10.0.1.138
The authenticity of host '10.0.1.138 (10.0.1.138)' can't be established.
RSA key fingerprint is b7:d2:a6:c0:95:77:b2:63:a8:d5:23:21:6f:32:b5:a2.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '10.0.1.138' (RSA) to the list of known hosts.
installer@10.0.1.138's password:

Once you get in, you should see the same installer root menu

Installer menu over SSH

Now, go ahead and define partitions, select packages, configure the boot loader and finish the installation. Easy, huh?

It's Debian All the Way Down

What I like best about all those lovely features of the Ubuntu installer is that they have been developed by the Debian guys and are present not only in the original Debian distributions, but in almost all Debian-based distributions too. For example, I bet all this works on shiny recent Linux Mint releases too.