Offline installation

Follow Pacman/Tips and tricks#Installing packages from a CD/DVD or USB stick for instructions on preparing a local repository with the necessary files on a separate host installation.

At the very least, for a functioning system, the following packages are recommended:

# pacman -Syw --cachedir . --dbpath /tmp/blankdb base base-devel linux linux-firmware systemd mkinitcpio vim

Create your custom offline repository

# repo-add ./custom.db.tar.gz ./*

Once the repository is prepared, connect the external media to the new installation, and mount it on the newly created root filesystem:

# mkdir /mnt/repo
# mount /dev/sdX /mnt/repo

Edit your archiso /etc/pacman.conf and add a new section:

[custom]
SigLevel = Optional
Server = file:///mnt/repo/

Comment out [core], [extra] and [community] so that pacman does not fail on the default repositories.

You can now continue to pacstrap your locally-available packages to the new installation:

# pacstrap /mnt base base-devel linux linux-firmware mkinitcpio systemd vim

In case the new system is expected to remain offline or airgapped, it should be configured to expect local repositories only.

After chrooting into your new installation, edit the new /etc/pacman.conf in the same way as previously (but without the /mnt prefix):

[custom]
SigLevel = Optional
Server = file:///repo/

Comment out all other repositories and save. Continue configuring the new system as usual.

From now on any updates to the offline system can be made by bringing an up to date copy of the local repository, mounting it to /repo and running pacman commands as usual.

Instead of installing the packages with pacstrap (which would try to download from the remote repositories), copy everything in the live environment to the new root:

# cp -ax / /mnt

Then, copy the kernel image to the new root, in order to keep the integrity of the new system:

# cp -vaT /run/archiso/bootmnt/arch/boot/$(uname -m)/vmlinuz /mnt/boot/vmlinuz-linux

After that, generate a fstab as described in Installation guide#Fstab.

Next, chroot into your newly installed system:

# arch-chroot /mnt /bin/bash

This customization of archiso will lead to storing the system journal in RAM, it means that the journal will not be available after reboot:

# sed -i 's/Storage=volatile/#Storage=auto/' /etc/systemd/journald.conf

This rule of udev starts the dhcpcd automatically if there are any wired network interfaces.

# rm /etc/udev/rules.d/81-dhcpcd.rules

Some service files are created for the Live environment, please disable pacman-init.service, and remove the file as they are unnecessary for the new system:

# rm -r /etc/systemd/system/{choose-mirror.service,pacman-init.service,etc-pacman.d-gnupg.mount,getty@tty1.service.d}
# rm /etc/systemd/scripts/choose-mirror

There are some scripts installed in the live system by archiso scripts, which are unnecessary for the new system:

# rm /etc/systemd/system/getty@tty1.service.d/autologin.conf
# rm /root/{.automated_script.sh,.zlogin}
# rm /etc/mkinitcpio-archiso.conf
# rm -r /etc/initcpio

In order to use the official repositories, we need to import the archlinux master keys (pacman/Package signing#Initializing the keyring). This step is usually done by pacstrap but can be achieved with

# pacman-key --init
# pacman-key --populate archlinux

Since you have copied the filesystem from the archiso, the needs to be edited in order for the proper initramfs to be installed. Open up in a text editor of your choice and comment/remove the only uncommented and replace with:

# HOOKS=(base udev autodetect modconf block filesystems keyboard fsck)

Now you can follow the skipped steps of the Installation guide#Configure the system section (setting a locale, timezone, hostname, etc.) and finish the installation by creating an initial ramdisk as described in Installation guide#Initramfs.