Deboostrap a debian system

deboostrap a debian system

Install debian without an iso.


Normally to install a linux distribution, you would download an iso, burn it to a usb with something like rufus or etcher, and then boot into it. But this can be timely and hard to automate, an experienced user may prefer to create a system from their already existing distribution.

create partition

Open gparted, create your ext4 root partition, if you have a separate media partition and dont plan to use steam games, then <30GB should be enougth. See dual booting linux for parition schemes.

  • get id of new parition
  • if your partition software hasn’t/can’t write a ext4 filesystem
      mkfs.ext4 /dev/[parition_id]
  • create a mountpoint and mount
    mkdir /mnt/deb
    sudo mount /dev/[parition_id] /mnt/deb

build system

This script will bootstrap a minimal debian or ubuntu system. Install

sudo apt install debootstrap

example options

  • variant, choose a minimal environment just for chroot or a full system
  • flavor choose a flavour/suite of debian, sid=unstable, bullseye=testing, buster=stable

    stable has old packages but is good for servers, otherwise testing gives more up to date packages

  • build dir: target dir to create the system, this should be the mounted partition
  • debian mirror: debian mirror to use to download the packages from, choose one close to your country
sudo debootstrap 
--variant=[minbase | buildd] \
[flavor] \
[build_dir] \
sudo debootstrap \
--variant=buildd \
bullseye \
/mnt/deb \


setup fstab

get uuid of mounted parition

sudo blkid | grep -w UUID=

copy your original fstab, and replace root uuid with uuid of mounted partition

sudo cp /etc/fstab /mnt/etc/fstab


Here the root is temporary changed to the debootstraped system. Allowing for us to run commands within it. Additional mounts are needed to get some programs within the chroot to work.

mount -t proc proc /mnt/deb/proc
mount -o bind /dev /mnt/deb/dev
mount -o bind /sys /mnt/deb/sys
chroot /mnt/deb


If not using a server, you will need to set your local timezone.

  • find your region in /usr/share/zoneinfo/[Region]/[City] and symlink
      ln -sf /usr/share/zoneinfo/Europe/Berlin /etc/localtime


If not using a server, you should configure and generate locales.

  • you can config locale from an interactive ncurses interface
    dpkg-reconfigure locales
  • or you can do it manually
      vi /etc/locale.gen 
          #uncomment your locale, EG for germany
          de_DE.UTF-8 UTF-8
          de_DE ISO-8859-1
          de_DE@euro ISO-8859-15
      vi /etc/locale.conf 
  • if you have a non-standard keyboard you may need to configure it
      dpkg-reconfigure keyboard-configuration
config network
echo -e `hostname` >> /etc/hostname
echo -e \ "\tlocalhost\n::1\tlocalhost\n127.0.1.1\t`hostname`.localdomain `hostname`" >> /etc/hosts

Rather than manually configure network interfaces, its much easier just to use network-manager.

apt install network-manager


  • set the root password
  • create a user and add them to the sudo group
      useradd username
      usermod -aG sudo username

install and config bootloader

Grub is the most widely used bootloader and will likely work with little config.

  • install, os-prober allows grub to search for other operating systems
    sudo apt install grub os-prober
  • check if system is efi or mbr
    • unless your computers quite old, it likely uses efi, /sys/firmware/efi only exists on efi systems
      ls /sys/firmware/efi
  • if efi
    • make sure your efi partition is mounted
    • install
        sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=debian-grub
    • usefull tool to manage efi partition in the future
        sudo apt install efibootmgr
  • if mbr, where sdX is your disk
      sudo grub-install --target=i386-pc /dev/sdX
  • generate config, grub will also detect any other operating systems
    sudo grub-mkconfig -o /boot/grub/grub.cfg

install kernel

  • search for a kernel
      apt-cache search linux-image
  • EG, the current default kernel for the amd64 architecture
      apt-get install linux-image-amd64

install any needed packages

install programs you want staright after reboot

apt-get install curl wget vim tmux

clean up chroot

unmount -R /mnt 
Ethan Hullett

Ethan Hullett
Student at Kent University