Installing Ubuntu using debootstrap
An updated version for Bionic is here
In some scenarios you may wish to install vanilla Ubuntu without the ability to use an iso.
In my case this was an OVH dedicated server which the default Ubuntu install they provide comes loaded with stuff I don't want.
First reboot into a rescue medium or separate install which is debian based and doesn't use the parition you want to install ubuntu on.
If the install OS is old you may need to run: apt-get update && apt-get -y upgrade To update debootstrap
If the install OS isn't ubuntu you may need to run: apt-get install ubuntu-archive-keyring
This guide assumes /dev/sda will be the root device and you will be installing a 64 bit arch.
First format your install disk using fdisk/cfdisk/parted/whatever your tool of choice is.
Next mount the install root:
mkdir /debootstrap
mount /dev/sda1 /debootstrap
Now install the base OS
debootstrap --arch=amd64 xenial /debootstrap
Replace xenial with whatever the codename of the distro to install is.
Now edit /debootstrap/etc/apt/soruces.list to include the following (again replacing xenial
with the codename)
#main repo
deb http://gb.archive.ubuntu.com/ubuntu/ xenial main
deb http://gb.archive.ubuntu.com/ubuntu/ xenial-updates main
#restricted repo
deb http://gb.archive.ubuntu.com/ubuntu/ xenial restricted
deb http://gb.archive.ubuntu.com/ubuntu/ xenial-updates restricted
#universe repo
deb http://gb.archive.ubuntu.com/ubuntu/ xenial universe
deb http://gb.archive.ubuntu.com/ubuntu/ xenial-updates universe
#multiverse repo
deb http://gb.archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://gb.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
#security repo
deb http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
Now set up device mounts etc and chroot to the new install
mkdir -p /debootstrap/dev /debootstrap/proc /debootstrap/sys
mount --bind /dev /debootstrap/dev
mount -t proc proc /debootstrap/proc
mount -t sysfs sys /debootstrap/sys
chroot /debootstrap
Set up the locale and timezone
cp /usr/share/zoneinfo/UTC /etc/localetime
echo 'LANG="en_US.UTF-8"' > /etc/default/locale
echo 'Etc/UTC' > /etc/timezone
locale-gen en_US.UTF-8
dpkg-reconfigure -f non-interactive tzdata
apt update
apt install language-pack-en-base
If you are using software raid, LVM or cryptsetup run
apt install lvm2 mdadm cryptsetup
Install the kernel and grub
apt install linux-image-generic grub2
Install openssh
apt install openssh-server
Important You must add your ssh key to /root/.ssh/authorized_keys by default ubuntu only allows key access for root
Add an fstab entry
echo '/dev/sda1 / ext4 errors=remount-ro 0 1' > /etc/fstab
Edit the network configuration, edit /etc/network/interfaces and add your config it may look like this:
auto eth0
iface eth0 inet dhcp
Now reboot and enjoy!