3.6.2 Proceeding with the Installation

With the target partitions ready and the target root mounted on /mnt, we’re ready to go. First, run:

herd start cow-store /mnt

This makes /gnu/store copy-on-write, such that packages added to it during the installation phase are written to the target disk on /mnt rather than kept in memory. This is necessary because the first phase of the guix system init command (see below) entails downloads or builds to /gnu/store which, initially, is an in-memory file system.

Next, you have to edit a file and provide the declaration of the operating system to be installed. To that end, the installation system comes with three text editors. We recommend GNU nano (see GNU nano Manual), which supports syntax highlighting and parentheses matching; other editors include mg (an Emacs clone), and nvi (a clone of the original BSD vi editor). We strongly recommend storing that file on the target root file system, say, as /mnt/etc/config.scm. Failing to do that, you will have lost your configuration file once you have rebooted into the newly-installed system.

See Using the Configuration System, for an overview of the configuration file. The example configurations discussed in that section are available under /etc/configuration in the installation image. Thus, to get started with a system configuration providing a graphical display server (a “desktop” system), you can run something along these lines:

# mkdir /mnt/etc
# cp /etc/configuration/desktop.scm /mnt/etc/config.scm
# nano /mnt/etc/config.scm

You should pay attention to what your configuration file contains, and in particular:

• Make sure the bootloader-configuration form refers to the targets you want to install GRUB on. It should mention grub-bootloader if you are installing GRUB in the legacy way, or grub-efi-bootloader for newer UEFI systems. For legacy systems, the targets field contain the names of the devices, like (list "/dev/sda"); for UEFI systems it names the paths to mounted EFI partitions, like (list "/boot/efi"); do make sure the paths are currently mounted and a file-system entry is specified in your configuration.
• Be sure that your file system labels match the value of their respective device fields in your file-system configuration, assuming your file-system configuration uses the file-system-label procedure in its device field.
• If there are encrypted or RAID partitions, make sure to add a mapped-devices field to describe them (see Mapped Devices).

Once you are done preparing the configuration file, the new system must be initialized (remember that the target root file system is mounted under /mnt):

guix system init /mnt/etc/config.scm /mnt

This copies all the necessary files and installs GRUB on /dev/sdX, unless you pass the --no-bootloader option. For more information, see Invoking guix system. This command may trigger downloads or builds of missing packages, which can take some time.

Once that command has completed—and hopefully succeeded!—you can run reboot and boot into the new system. The root password in the new system is initially empty; other users’ passwords need to be initialized by running the passwd command as root, unless your configuration specifies otherwise (see user account passwords). See After System Installation, for what’s next!