Debian headless/remote installation

I wanted to do a headless installation for a server – i.e. without any keyboard access or the chance to peek at a temporarily connected screen. I found plenty of information on the net but none of the tutorials really worked for me. Some included preseeding the image but failed to automatically start the installation without a key press, others seemed to customize a zillion things but ended up getting stuck in some error message or other.

So I read my way through all of them and put together a slim working solution – at least working for me. So here is my minimal and lazy solution to debian headless installation image building. I mostly documented it for myself but maybe it's useful for someone out there.

I have tested this with Debian 9.5 (aka stretch) on an amd64 machine (Lenovo Thinkcentre Tiny m600). I think this should work with other versions (probably also ubuntu) and architectures but that is untested. If you have tested this please let me know and/or contribute code.

At this point, this does not currently support UEFI boot! So make sure that you system will use legacy boot, by default.

In a nutshell

# Get a netinst image 
wget https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-9.5.0-amd64-netinst.iso
# Edit config.txt
vim config.txt
# Edit.create preseed-XXX.cfg 
vim preseed-XXX.cfg
# Build image
make image
# OPTIONAL: test iso image in qemu
make qemu
# Write image to usb stick
make usb
# optional: Add a FAT32 partition on the remaining free space
make FAT

Dependencies

Make sure all necessary tools are installed:

sudo apt-get install bsdtar syslinux syslinux-utils cpio genisoimage coreutils qemu-system qemu-system-x86 util-linux

Or

make install-depends

Download the debian installation image

Download the Debian installation image (netinst) and put it in this folder.

https://www.debian.org/distrib/netinst

Configure some things

Edit the makefile and set some variables to match your situation. e.g.

SOURCE = debian-9.5.0-amd64-netinst.iso
TARGET = debian-9.5.0-amd64-netinst-preseed.iso
ARCH = amd
QEMU = qemu-system-x86_64 
LABEL = debian-9.5.0-amd64-headless
USBDEV = /dev/sdc

ARCH indicates the target processor architecture – amd or 386 This variable is used to construct the correct folder name (install.amd) for initrd. LABEL is the CD volume label and USBDEV is the device that represents your usb stick. The latter is needed for make usb and make FAT Be extra careful to set USBDEV correctly! If you set it incorrectly, you may overwrite your system disk! QEMU is the name of the qemu-system binary that matches the target architecture (optional).

This script comes with a few preseed-xx_XX.cfg files. They contain the bare minimum for a headless installation. The files differ in the keymap and language settings. You may want to edit one of these files or create your own to adapt it to your needs. This is also the place to configure the login password for the network installation. For comprehensive information on preseeding study this: https://www.debian.org/releases/stable/i386/apb.html

Build the ISO

make clean
make image

Dry run it

This step is optional but may save you a lot of trouble later on.

make qemu

This will fire up a QEMU session booting your new image. You can follow the boot process in the emulator and eventually connect to the installer like this:

ssh installer@localhost -p10022

So you can test-drive the installation before walking over to the server room.

Write to usb stick or burn cd

If you still have a cdrom drive, use your favorite ISO burner to write the image to cd. I can't find my old usb-cd drive and prefer using a usb stick, anyway:

Insert a USB stick and find out its device file

lsblk

Double check, that USBDEV ist set correctly in the Makefile.

Caution: The next two steps will write to the device configured in the USBDEV. If you failed to set that correctly, you will overwrite whatever disk happens to be associated with that device!

Write the image to the stick:

make usb

Add a FAT partition to the stick

make FAT

This may be useful if you need to add custom firmware files or anything else you would like to use during installation.

Installation

At the moment, UEFI boot is not supported so make sure you system uses legacy boot, by default.

Insert the USB stick (or CD) in the target system and power it up. Find out the IP address of the machine (e.g. from the router/DHCP server). Alternatively, configure static IP in the preseed file. Once the system is up you should be able to ping it. Now log in and complete the installation:

ssh installer@yourmachine

The default password is MyGreatSecret and can be configured in the preseeding file. Alternatively, set a host key in preseeding for passwordless login.

BTW: my preseed.cfg assumes that we are connected via ethernet (as a server should be). If you want to/must use a wifi connection you need to configure this.