My Arch Linux Installation: systemd-boot, LUKS, Btrfs, swapfile and xmonad

Table of Contents

Before the installation

Save things that you need to be saved

The public and private GPG keys:

gpg --export --armor > public.key
gpg --export-secret-key --armor > private.key

Your shared GPG and SSH files.
Your data.

REMEMBER: if you have some dotfiles or other projects in your PC, make sure that you have pushed your changes.

Make sure the drive security is not frozen

If you are running a pre-installed system, you can cleaning all the storage (in my case, a SSD NVMe), you can wipe your storage to clean all things inside it. To do it on a SSD NVMe, you can do these things:

Run the following command:

nvme id-ctrl /dev/nvme0 -H |grep "Format \|Crypto Erase\|Sanitize"

Erase all data from your storage (SSD NVMe)

You can run the ‘nvme sanitize` command to erase all data from the storage. You can see an example of the command here:

nvme sanitize <device> -a <action>

The possible actions that you can use is:

-a <action>
--sanact=<action>
    Sanitize Action
    000b - Reserved
    001b - Exit Failure Mode
    010b - Start a Block Erase sanitize operation
    011b - Start an Overwrite sanitize operation
    100b - Start a Crypto Erase sanitize operation

ATTENTION: When you running the sanitize command, you should replace your binary value by their decimal part, e.g. 000b = 0, 001b = 1, 010b = 2, etc…

References

Wipe on an Empty Disk

Create a temporary encrypted container on the complete device to be encrypted

cryptsetup open --type plain -d /dev/urandom /dev/nvme0n1 to_be_wiped

Wipe the container with zeros

dd if=/dev/zero of=/dev/mapper/to_be_wiped bs=4096 status=progress

Installation

Disk partitioning (UEFI)

The partiotining that follows the concerns the UEFI installation.

Introduction

First of all, I have differente names for the partitions, but don’t be lost for so little:

Mount point	Partition name	Partition type	Bootable flags	Size
/boot	/dev/nvme0n1p1	EFI System	Yes	1 Gb
/	/dev/nvme0n1p2	Linux LVM	No	Remainder of the device

Where / will be a LVM-encrypted partition having a group volume containing a physical volume and rootas a logical volume.

Finally, as mentioned in the introduction, we will format the / volume as Btrfs and create two sub-volume:

/root
swap
/home

Creation of the File System

In order to know the name of your disk, it is necessary to list the partition tables for the specified device:

fdisk -l

Let’s select our disk to build the table:

cfdisk /dev/nvme0n1

Then create a new empty GPTpartition table.

And now, you can setup all the partiions in a “visual” way.

Setup the Disk Encryption

In order to enable disk encryption, we will first create a root LUKS volume, open it and then format it.

In a brief explaination, LUKS is a container format that will be used to encrypt containers, where our encryption key will be stored.

Creation of a root LUKS volume

To encrypt our / partition, we will use the cryptsetup tool:

cryptsetup --hash sha512 --use-random --verify-passhphrase luksFormat /dev/nvme0n1p2
Are you sure? YES
Enter passhphrase (twice)

Opening the root LUKS volume as block device

The / partition being encrypted, we will open the LUKS container on /dev/nvme0n1p2 disk and name it cryptlvm:

cryptsetup open /dev/nvme0n1p2 cryptlvm
Enter passhphrase

The decrypted container is now available at /dev/mapper/cryptlvm.

Setup the LVM

LVM is a logical volume manager for the Linux kernel. It is thank to to it that we can easily resize our partitions if necessary.

Create a physical volume on top of the opened LUKS container

pvcreate /dev/mapper/cryptlvm

Add the previously created physical volume to a volume group

vgcreate vg /dev/mapper/cryptlvm

Create the swap logical volume on the volume group

Create the root logical volume on the volume group

lvcreate -l 100%FREE vg -n root

Formatting the filesystem

mkfs.fat -F32 /dev/nvme0n1p1
mkfs.btrfs -L btrfs /dev/mapper/vg-root

Btrfs subvolumes

Subvolumes are part of the filesystem with its own and independnet file/directory hierarchy, where each subvolume can share file extents.

Create Btrfs subvolumes

mount /dev/mapper/vg-root /mnt
btrfs subvolume create /mnt/root
btrfs subvolume create /mnt/home
umount /mnt

Mounting Btrfs subvolumes

SSD_MOUNTS="autodefrag,compress=lzo,discard,noatime,nodev,rw,space_cache,ssd"
mount -o subvol=root,$SSD_MOUNTS /dev/mapper/vg-root /mnt
 
mkdir -p /mnt/{boot,home}
 
mount -o discard,noatime,nodev,noexec,nosuid,rw /dev/nvme0n1p1 /mnt/boot
mount -o $SSD_MOUNTS,nosuid,subvol=home

Some details about the option on -o flag:

autodefrag: enable automatic file defragmentation for small random writes in files with a maximum file size of 64K;
compress=lzo: compresses files with the lzo type which is a lossless data compression algorithm that is focused on decompression speed;
discard: enable discarding of freed file blocks using TRIM operation (useful for SSD devices);
noatime: allows measurable performance gains by eliminating the need for the system to write to the file system for files that are simply read;
nodev: disallows creating and accessing device nodes (used in particular for special files in /dev);
noexec: does not allow the execution of executable binaries in the mounted file system;
nosuid: specifies that the filesystem cannot contain set userid files;
rw: allows reading and writing;
space_cache: control the free space cache. This greatly improves performance when reading block group free space into memory;
ssd: by default, Btrfs will enable or disable SSD allocation heuristics depending on whether a rotational or non-rotational device is in use.

Base system

Update the mirrors

pacman -S reflector
reflector --threads 8 --protocol http --protocol https --verbose --sort rate --country Brazil --save /etc/pacman.d/mirrorlist

Installation of the packages onto a given root file system

pacstrap /mnt base linux-firmware linux-zen lvm2 sudo man-db base-devel linux-tools git hdsentinel fwupd sudo

Configuration of the system

We will configure the system base in order to have a decent environment.

Generate a fstab file

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

Change root into the new system

arch-chroot /mnt

Create the swap file

To create the swap file, we will create a zero length file, set the No_COW attribute and make sure compression is disabled:

truncate -s 0 /swapfile
chattr +C /swapfile
btrfs property set /swapfile compression none

Is recommended to set the size of swap file being 4-8GB if you don’t intend to use hibernation (suspend-to-disk):

dd if=/dev/zero of=/swapfile bs=1M count=16384 status=progress && sync

Set the permission for the file (a world-readable swap file is a huge local vulnerability):

chmod 600 /swapfile

Format the /swapfile file to swap and activate it:

mkswap /swapfile
swapon /swapfile

Finally, add an entry for the swap file in the fstab:

echo "/swapfile none swap defaults 0 0" >> /etc/fstab

Set the timezone

Install the Network Time Protocol and enable it as daemon:

pacman -S ntp
systemctl enable ntpd

Create a symlink of the timezone:

ln -sf /usr/share/zoneinfo/America/Sao_Paulo /etc/localtime

Generate /etc/adjtime:

hwclock --systohc

Network configuration

Install and enable network management daemon:

pacman -S networkmanager
systemctl enable NetworkManager

So add a hostname to the machine:

echo ThinkPad > /etc/hostname

NOTE: Remember that you can replace ThinkPad with whatever you like.

Add matching entries to /etc/hosts:

127.0.0.1  localhost
::1     localhost
127.0.1.1  ThinkPad.localdomain ThinkPad

Set the root passsword

passwd

Create the main user

useradd -mG storage,wheel -s /bin/bash someone
passwd someone

Finally, change the /etc/sudoers file according to the config that you want to deal with sudo command.

Create a initial ramdisk environment

nano /etc/mkinitcpio.conf

You should the HOOKS field with these things:

...
HOOKS=(base systemd autodetect keyboard sd-vconsole modconf block sd-encrypt lvm2 filesystems btrfs)
...

Finally, recreate the initramfsimage:

mkinitcpio -p linux-zen

Setup the boot manager

Install `systemd-boot` into the EFI system partition

bootctl install

Configuring the loader

On /boot/loader/loader.confinsert this:

default arch
timeout 10
console-mode max
editor no

Some details about the parameters:

default: default entry to select;
timeout: menu timeout in second, useful to allow people who have multiple operating systems;
console-mode: changes UEFI console mode;
editor: whether to enable the kernel parameters editor or not. Strongly recommended to set this option to no to avoid bypass root password and gain root access.

Adding the loader

First install the microcode:

pacman -S amd-ucode

After it, insert on /boot/loader/entries/arch.conf this:

title Arch Linux
linux /vmlinuz-linux
initrd /intel-ucode.img
initrd /initramfs-linux.img
options rd.luks.name=$(blkid /dev/nvme0n1p2 -s UUID -o value)=cryptlvm rd.luks.options=discard root=/dev/mapper/vg-root resume=/dev/mapper/vg-root rootfstype=btrfs resume_offset=$(filefrag -v /swapfile | sed '4q;d' | awk '{print $4}' | cut -d'.' -f1) quiet nowatchdog splash rw

Graphical environment

Install the window manager

First of all, install xorg:

pacman -S xorg-server

Finally, install the xmonad:

pacman -S xmonad xmonad-contrib

Install a display manager

pacman -S lightdm
systemctl enable lightdm

Install a AUR helper

git clone https://aur.archlinux.org/yay.git
cd yay
makepkg -sri
cd .. && rm -r yay

Keyring

pacman -S gnome-keyring seahorse

Terminal

pacman -S alacritty tmux

Shell

pacman -S fish

Image manipulations

pacman -S gimp inkscape

NTFS

pacman -S ntfs-3g

Sound system

pacman -S pulseaudio alsa-utils pavucontrol alsamixer

Other

In order to save the read and write cycles of the SSD and thus extend the lifetime of the SSD, the browser profile can be moved in RAM with profile-sync-daemon:

pacman -S profile-sync-daemon

Finally, enable and activate the service:

systemctl --user enable psd --now

After installation

Enable fstrim

First enable and start fstrim timer. On Arch-based system you can do it running this commands:

sudo systemctl enable fstrim.timer
sudo systemctl start fstrim.timer

After this, if you running with LUKS encryption, you should add some things on the Arch entry from systemd-boot, inside /boot/loader/entries/arch.conf, add it:

...
options rd.luks.name=<UUID>=cryptlvm ... rd.luks.options=discard
...

Reboot the system. And now, you can check if it’s running correctly executing this command: lsblk --discard. If has no-zero entries on DISC-GRAN and DISC-MAX columns means TRIM is enabled.

References

Disable `watchdog`

Append on your boot parameters (probably /boot/loader/entries/arch.conf) the following option:

...
options rd.luks.name=<UUID>=cryptlvm ... nowatchdog
...

After it, you can optionally disable the loading of the module responsible of the hardware watchdog, too. Do it blacklisting the related module.

Creating a .conf inside /etc/modprobe.d/ and append a line for the module you want to blacklist with blacklist keyword. Here an example:

# /etc/modprobe.d/nowatchdog.conf
blacklist iTCO_wdt

References

Arch Linux: Improving performance - Watchdogs

Troubleshooting

Thinkpad T14 Gen 1 Brazillian keyboard layout

If you are using this installation on a Thinkpad T14 Gen 1 with a Brazillian keyboard layout (ABNT2) like me, you should use this rule to turns the keyboard usable. You should run this command:

setxkbmap -model thinkpad60 -layout br -variant anbt2

Or just paste the “text” below on the following path: /etc/X11/xorg.conf.d:

Section "InputClass"
 Identifier "system-keyboard"
 MatchIsKeyboard "on"
 Option "XkbLayout" "br"
 Option "XkbModel" "thinkpad60"
 Option "XkbVariant" "abnt2"
EndSection

My Arch Linux Installation: systemd-boot, LUKS, Btrfs, swapfile and xmonad

Install systemd-boot into the EFI system partition

Disable watchdog

Install `systemd-boot` into the EFI system partition

Disable `watchdog`