Encrypted Arch Linux Installation

Jul 5, 2020 5 min read
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Since a few years, I’m a big fan of Arch Linux: Always up to date packages and no major release upgrades, due to its rolling releases philosophy. And minimal installations only packed with the tools you need.

So I’ve got a new device and I had to install it from scratch, including LUKS encryption and the slim systemd-boot.

Foreword

If you encounter any problems, always refer to the original up to date Arch Installation Guide. This post will become out-dated but still may be helpful for certain aspects.

Pre-Installation

Create your live USB stick with dd or Balea-Etcher and a fresh Arch ISO Image and boot into the live environment.

Keyboard Layout

The first thing you may need to do is to set up the keyboard layout. For a german layout, use the following command: loadkeys de.

Available layouts can be listed via ls /usr/share/kbd/keymaps/**/*.map.gz.

Verify UEFI Boot Mode

The next thing you want to check is, that you’re using the UEFI boot mode since we want to use systemd-boot: ls /sys/firmware/efi/efivars

If the command lists the directory, the system is booted in UEFI mode. Perfect :)

Connect to the Internet

You can connect to your wireless network via iwctl:

iwctl
device list
station wlan0 connect YOUR-SSID

Also updating the system clock is a good idea: timedatectl set-ntp true

Partitioning

We will use an LVM partition with the LUKS encryption. First, find out your disk you want to partition: Just use the command lsblk. Your disk should be named like /dev/sda or /dev/nvme0n1.

Creating Partitions

Using gdisk, start gdisk /dev/nvme.... If asked, yes you want to create a new Partition Table. If gdisk doesn’t ask for it, force it by pressing o.

First, we are going to create the boot partition:

  • Press n to create a new partition.
  • Press Enter to accept the suggested partition number
  • Press Enter to accept the first sector
  • As the last sector, enter +512M to create a 512MB sized partition and press Enter
  • As Partition Type, enter ef00 since we want to create an EFI system partition and press Enter

The second partition will become the encrypted main partition:

  • Press n to create a new partition.
  • Press Enter to accept the suggested partition number
  • Press Enter to accept the first sector
  • Press Enter to accept the last sector, the partition shall use the entire space
  • As Partition Type, enter 8e00 for LVM, and press Enter again

After saving your new partition layout, we can format the boot partition with the following command: mkfs.fat -F32 /dev/nvme...p1

Adding Encryption

After creating the LVM partition, we have to encrypt it.

  • modprobe dm-crypt
  • cryptsetup luksFormat /dev/nvme...p2 and set your password
  • Open the partition again: cryptsetup open --type luks /dev/nvme...p2 lvm

Creating more Volumes

Now we can partition the LVM partition and add volumes.

  • pvcreate /dev/mapper/lvm
  • vgcreate main /dev/mapper/lvm
  • Create a swap volume: lvcreate -L18G main -n swap. A recommended size is to use your amount of RAM + 2GB
  • Create your main volume: lvcreate -l 100%FREE main -n root

Note: I don’t use a dedicated home volume. You may want to create your root volume with a smaller size (for example 40G) and give your home volume 100%FREE space.

Now we can format the new volumes:

  • mkswap /dev/mapper/main-swap
  • mkfs.ext4 /dev/mapper/main-root

Mounting the Partitions and Volumes

  • mount /dev/mapper/main-root /mnt
  • mkdir /mnt/boot
  • mount /dev/nvme...p1 /mnt/boot
  • swapon /dev/mapper/volume-swap

Installation

Start the installation by installing the basics to your new environment:
pacstrap /mnt base base-devel linux linux-firmware lvm2 man-db man-pages texinfo vim
Note: You will need the additional lvm2 package later :)

Fstab

Generate your fstab file with the following command: genfstab -U /mnt >> /mnt/etc/fstab

Initial Setup

Now chroot into your new installation: arch-chroot /mnt. From now on, we will work inside your new system.

Setting the Time Zone

You may want to change Europe/Berlin to your time zone:
ln -sf /usr/share/zoneinfo/Europe/Berlin /etc/localtime

Localization

Edit /etc/locale.gen and uncomment en_US.UTF-8 UTF-8 and other locales you need. Then generate them via locale-gen.

Now create the file /etc/locale.conf and set the LANG variable to your desired and generated default locale. In my case LANG=de_DE.UTF-8.

Create another file called /etc/vconsole.conf and enter your default keyboard layout: Again, in my case: KEYMAP=de

Network Configuration

Now the hostname: Enter your desired hostname in /etc/hostname (for example “my-laptop”) and edit the hosts file /etc/hosts accordingly:

# Static table lookup for hostnames.
# See hosts(5) for details.
127.0.0.1  localhost my-laptop
::1        localhost my-laptop
127.0.1.1  my-laptop.localdomain my-laptop

Enabling En/Decryption on Boot

Before we create the initramfs, we have to edit the HOOKS variable. Edit the file /etc/mkinitcpio.conf and look for the HOOKS variable. We have to place the keyboard before the filesystem and add encrypt and lvm in-between.

It should look similar to this now:

HOOKS="base udev autodetect modconf block keyboard encrypt lvm2 filesystems fsck"

Initramfs

Create the initramfs via mkinitcpio -P.

Bootloader

To install the systemd-boot bootloader, call bootctl --path=/boot/ install.

Now edit the file /boot/loader/loader.conf to select the arch profile as default:

default arch
editor 0

Afterwards, create the arch profile in /boot/loader/entries/arch.conf:

title Arch Linux
linux /vmlinuz-linux
initrd  /initramfs-linux.img
options cryptdevice=/dev/nvme...p2:main root=/dev/mapper/main-root resume=/dev/mapper/main-swap lang=de locale=de_DE.UTF-8

You have to change the device, lang, and locale here for your needs.

Root Password

At last, define a root password via passwd and you are done. At least almost…

Post-Installation (IMPORTANT)

In the previous steps, you’ve installed a somewhat basic Arch Linux. You have to add more packages before you reboot into your system if you want to connect to the Internet, etc. :)

See the Arch Linux General Recommendations for more information.

Reboot into your Installation

Exit the chroot environment via exit. Unmount via umount -R /mnt and finally reboot.

Have fun with your new Arch Linux system. <3

Florian Brinker
I'm a Software-Developer based in Germany, enjoying home automation topics, microcontrollers, space- and quantum physics, astro- and landscape photography and mountainbiking.