Minimal Ubuntu Install

This article will walk through a minimal and manual installation of Ubuntu, comparable to the Arch Linux installation process.

Inspired by the following Reddit Post: Passing the Time in Quarantine (Installed Ubuntu the Arch Way)

Setup:

Boot Into Live Environment:

  • Download the latest desktop or server Iso (I would recommend the desktop Iso for simplicity).
  • Create bootable media (using something like Etcher), then boot off of your live media.
  • Make sure to select “Try Ubuntu” not “Install Ubuntu” when you get to the Grub menu options.

Requirements:

Make sure your Ubuntu environment has a network connection. If you used the desktop Iso, just use the Network Manager applet in the top right hand corner to connect. I will not get into the details of getting wifi connected via CLI, just use an ethernet cable if you can’t figure it out.

I will assume that UEFI is desired boot mode.

I will also assume that you have elevated to root to run all the remaining commands (sudo su -).

Installation:

Dependencies:

## Add the Universe repository for arch-install-scripts
add-apt-repository universe

apt-get update
apt-get install -y debootstrap arch-install-scripts

Disk Partitioning:

List your disks and their partitions with the following command:

lsblk

The output will show a list of disks, their partitions and their sizes. My disk is an 80 GB drive named /dev/sda. Change your drive paths as needed in the following commands to fit your installation.

Now, let’s edit the drive partitions with gdisk

gdisk /dev/sda

Create the EFI partition:

Press n, 1 [Enter], [Enter], +512M [Enter], ef00 [Enter]

Create the swap partition (I’m just going to use 4GB of swap space):

Press n, 2 [Enter], [Enter], +4G [Enter], 8200 [Enter]

Create the root partition:

Press n, 3 [Enter], [Enter], [Enter], [Enter]

Write the changes:

Press w, Y [Enter]

Partition Formatting:

Use the following commands to format your disk.

mkfs.vfat /dev/sda1

mkswap /dev/sda2 && swapon /dev/sda2

mkfs.btrfs /dev/sda3

Bootstrap Ubuntu:

Mount the partitions we created earlier:

mount /dev/sda3 /mnt
mkdir -p /mnt/boot/efi && mount /dev/sda1 /mnt/boot/efi

Then bootstrap your base Ubuntu install (using Ubuntu 20.04 “Focal Fossa”):

debootstrap --arch amd64 focal /mnt http://archive.ubuntu.com/ubuntu

Edit /mnt/etc/apt/sources.list to not only have the main repository but also universe (community packages) and restricted (proprietary drivers) and the security repo:

release="focal"

printf "deb http://archive.ubuntu.com/ubuntu/ ${release} main restricted universe\ndeb http://security.ubuntu.com/ubuntu/ ${release}-security main restricted universe\ndeb http://archive.ubuntu.com/ubuntu/ ${release}-updates main restricted universe\n" > /mnt/etc/apt/sources.list 

Create a new fstab for the new installation:

genfstab -U /mnt >> /mnt/etc/fstab

Look at /mnt/etc/fstab and fix any errors if needed.

Configuring Ubuntu:

Chroot into the new installation:

arch-chroot /mnt

Update repository data and install additional dependencies (modify packages as needed):

apt-get update

## Necessary dependencies
apt-get install -y --no-install-recommends linux-generic linux-image-generic linux-headers-generic initramfs-tools linux-firmware efibootmgr

## Optional/opinionated dependencies
apt-get install -y vim

Set timezone:

dpkg-reconfigure tzdata

Set locale (I use en_US.UTF-8):

dpkg-reconfigure locales

Set hostname:

Edit /etc/hostname to equal whatever value you want your computer name to be:

echo 'myhostname' > /etc/hostname

I would also recommend editing /etc/hosts as described in the Arch wiki:

Arch Wiki: Network Configuration

127.0.0.1	localhost
::1		localhost
127.0.1.1	myhostname.localdomain	myhostname

Set root password:

passwd

Then install your preferred desktop environment, display manager, etc. I’ll just use GNOME Shell + GDM as an example because I’m boring:

apt-get install -y gnome-shell gnome-terminal gdm3 firefox

Add a sudo user:

adduser myusername

usermod -aG sudo myusername

Create new directories:

mkdir -p /boot/efi/ubuntu/
mkdir -p /boot/efi/loader/entries

Create a systemd-boot config file /boot/efi/loader/loader.conf with the following lines:

default ubuntu
timeout 1
editor 0

Then create a boot entry file in /boot/efi/loader/entries/ubuntu.conf, replacing the PARTUUID with the root partition found with blkid:

title   Ubuntu
linux   /ubuntu/vmlinuz-generic
initrd  /ubuntu/initrd.img-generic
options root=PARTUUID=YOUR_UUID rw

The only problem with using systemd-boot is that you’d need to manually update the kernels any time a new version of the Linux kernel is installed. To solve this, we will create a post install hook that will update the kernel entries in systemd-boot.

Create /etc/kernel/postinst.d/update-systemd-boot with the following content, replacing the PARTUUID variable value with the value of your root PARTUUID found from blkid:

#!/bin/bash
#
# This is a simple custom kernel hook to populate the systemd-boot entries
# whenever kernels are added or removed during an update.
#


# The PARTUUID of your root partition
PARTUUID="INSERTYOURPARTUUIDHERE"

vmlinuz=$(find /boot -maxdepth 1 -name "vmlinuz-*-generic")
version=$(echo $vmlinuz | grep -o -P "\d+\.\d+\.\d+\-\d+" | sort -V | head -n -1)
latest=$(echo $vmlinuz | grep -o -P "\d+\.\d+\.\d+\-\d+" | sort -V | tail -n 1)

echo ">> COPYING ${latest}-generic. LATEST VERSION."

cat << EOF > /boot/efi/loader/entries/ubuntu.conf
title   Ubuntu
linux   /ubuntu/vmlinuz-generic
initrd  /ubuntu/initrd.img-generic
options root=PARTUUID=${PARTUUID} rw
EOF

for file in initrd.img vmlinuz; do
    cp "/boot/${file}-${latest}-generic" "/boot/efi/ubuntu/${file}-generic"
done

for ver in $version; do

    echo ">> COPYING ${ver}-generic."

cat << EOF > /boot/efi/loader/entries/ubuntu-${ver}.conf
title   Ubuntu ${ver}
linux   /ubuntu/vmlinuz-${ver}-generic
initrd  /ubuntu/initrd.img-${ver}-generic
options root=PARTUUID=${PARTUUID} rw
EOF

    for file in initrd.img vmlinuz; do
        cp "/boot/${file}-${ver}-generic" "/boot/efi/ubuntu/${file}-${ver}-generic"
    done
done

Make the script executable and symlink it to another relevant location:

chmod +x /etc/kernel/postinst.d/update-systemd-boot
ln -s /etc/kernel/postinst.d/update-systemd-boot /etc/kernel/postrm.d/update-systemd-boot

Setup Systemd-boot:

bootctl --path=/boot/efi install

Now, execute the hook script to move the kernel images to the correct directories for our systemd-boot config to recognize them:

/etc/kernel/postinst.d/update-systemd-boot

Verify boot entries:

bootctl list

I have noticed that Ubuntu has this annoying habit of installing Grub for you, so let’s prevent grub packages from installing:

Place the following in /etc/apt/preferences.d/grub:

Package: grub-common grub-gfxpayload-lists grub-pc grub-pc-bin grub2-common
Pin: release *
Pin-Priority: -1

Exit:

Use the exit command to get out of the chroot.

Then reboot!

reboot
Written on April 3, 2020