Review of installation manual draft

[Petter]

Hi,

During the last week on IRC a few of us have been putting together a 
proposal for updating the GuixSD installation instructions in the 
manual. It was initially intended to be a guide for how to install 
GuixSD with encrypted root to the Libreboot site; but as the steps are 
generic, and the GuixSD manual doesn't address this we thought we'd make 
a proposal here instead. The instructions for encrypted root are quite 
detailed, and to try and keep the entire installation manual in the same 
vein, other steps have been redone with detailed, step for step, 
instructions. Which will hopefully make it easier for less experienced 
users to get GuixSD up and running, with or without encryption.

First of all we'd like to know if there are any major issues/objections 
with this proposal, issues that would result in restructuring, or even 
that we drop it altogether. Better we know now before going into polish 
mode. We're also very interested in comments and suggestions to make it 
better of course.

Current issues:
 - typing in the mapped-devices field perfectly is error-prone, maybe 
put a commented out mapped-devices field in the example configuration 
instead and the manual will say to enable it for users opting for 
encryption.
 - it would be nice to print a list of available layouts for the 
loadkeys command. Please let me know if you know how to do this.
 - maybe elaborate on how to use cfdisk and/or similar tools

Ideas:
 - maybe it would be good to use a dedicated bare-bones config for (1) 
fully encrypted, (2) encrypted root without /boot, (3) encrypted /home, 
(4) unencrypted; to get people up and running quickly, then add desktop 
environment etc. in a post-installation document.

Thanks,
Petter

------------------current draft-------------------------------

7.1.3 Booting the installation image
Once you have successfully booted the image on the USB stick, you should 
end up with a root prompt. Several console TTYs are configured and can 
be used to run commands as root. TTY2 shows this documentation, 
browsable using the Info reader commands (see Help in Info: An 
Introduction).



7.1.3.1 Keyboard
The installation image uses the US Qwerty keyboard layout. To change you 
can use the "loadkeys" command with your preferred layout. Example 
<layout>: "dvorak".
# loadkeys <layout>



7.1.3.2 Network
Run this to see what your network interfaces are called:
# ifconfig -a

To configure the network run this command, substituting 
<network-interface> with the one you want to use. Example 
<network-interface>: "eno1".
# ifconfig <network-interface> up && dhclient <network-interface>

Try to ping a server to see if a connection was established. For 
example, gnu.org.
# ping -c 3 gnu.org

If ping fails with a `ping: unknown host` error, first check if there is 
an issue with your cable. If not, try to restart nscd.
# deco restart nscd





7.1.4 Preparing the disk
First you need to decide if you want encrypted root or not. If you're 
going for unencrypted skip to the next paragraph. For encrypted root you 
need to figure out if you can have /boot encrypted or not. For /boot to 
be encrypted you need boot firmware with an embedded boot loader, such 
as Coreboot/Libreboot. Otherwise you'll need to leave /boot unencrypted, 
in this case create a separate partition for it. 100 MB should be 
enough, make it type "Linux (83)".

Your main partition will be where you install root (/). If you're going 
to install a desktop this partition should be at least 15 GB. Make it 
use the rest of your disk (after potentially making a boot partition) if 
you don't know how large to make it. Make it type "Linux (83)"



7.1.4.1 Disk partitioning
Before proceeding with partitioning you need to be sure about the device 
name of the disk you're installing to. Example "/dev/sda"
For partitioning there are several tools available, cfdisk is one.
# cfdisk /dev/<disk>

If you went for unencrypted we'll refer to your root partition as 
"<your-root-partition>".
If you went for encrypted we'll refer to your encrypted root partition 
as "<your-encrypted-root-partition>". Any separate partition for /boot 
will be referred to as "<your-boot-partition>".
Typical value: "sda1".



7.1.4.2 Disk encryption
Skip this chapter if you're not doing encrypted root.

Encrypt the encrypted partition with LUKS, using your favorite 
cryptsetup invocation, for example:
# cryptsetup -v --cipher serpent-xts-plain64 --key-size 512 --hash 
whirlpool --use-random --verify-passphrase luksFormat 
/dev/<your-encrypted-root-partition>

Open the LUKS partition. You can verify its effect by doing "ls 
/dev/mapper" before and after this command, on success a "guixsd" file 
will appear.
# cryptsetup luksOpen /dev/<your-encrypted-root-partition> guixsd

We'll later refer to your mapped device (f.ex. "mapper/guixsd") as 
"<your-root-partition>".



7.1.4.3 Filesystem and mount
Make a filesystem, f.ex. ext4. For unencrypted root you can use the "-L" 
flag, with a string argument, to create a label for later reference.
# mkfs.ext4 /dev/<your-root-partition>

Mount it under /mnt
# mount /dev/<your-root-partition> /mnt

Run this command to make /gnu/store copy-on-write, such that packages 
added to it during the installation phase will be written to the target 
disk rather than kept in memory.
# deco start cow-store /mnt

Create the /etc on your mounted partition
# mkdir /mnt/etc





7.1.5 Preparing the configuration file
Now we're going to prepare the configuration file. There are two example 
configuration files available in the live image, located in 
/etc/configuration.
"bare-bones.scm" is a minimal configuration with no X11 display server.
"desktop.scm" will install some desktop environments.
Even if you want a desktop eventually you can start with 
"bare-bones.scm"; and once you're able to boot properly add X11 and 
desktop environments etc. to your configuration and reconfigure your 
system. This will save you time if you run into problems and need to 
install GuixSD again.
# cp /etc/configuration/bare-bones.scm /mnt/etc/config.scm

Now we'll open and modify the configuration file. The live image comes 
with two text editors: GNU nano (see GNU nano Manual), and GNU Zile, an 
Emacs clone. Open your configuration file with one of them.
# zile /mnt/etc/config.scm

We'll do the updates in turn from top to bottom. you'll recognize some 
of the crypto steps from earlier, but note that previously we've been 
setting up the partition for the installation. These steps gives 
instructions to be used when booting the system.

Adjust "host-name", "timezone" and "locale" to your wishes. If you're 
going to change locale you should check what is available and exactly 
how it is typed; close the editor or change virtual console 
(Ctrl-Alt-F#), and run the command "locale -a".

Update "device" in the bootloader field to "/dev/<disk>". This will 
instruct the installation to install GRUB to the MBR of your disk. This 
is fine even if you're going to use the boot loader in your boot 
firmware, it will just be unused in this case.



7.1.5.1 Special configuration for encrypted root
Skip this chapter if you're doing unencrypted root.

For encrypted root setups we need to add some lines to the configuration 
with instructions on how do decrypt your partition during boot. Add the 
"mapped-devices" field below to your your operating-system declaration.
(If that last sentence didn't make much sense: Insert the code snippet 
below between the lines (bootloader ...) and (file-systems ...))
Make sure to update the following fields:
"source", the device name of your encrypted partition. Example 
"/dev/sda1"
"target", a name you make up that will appear in /dev/mapper/ after 
decryption. We'll later refer to this as "<target-name>". Example 
"guixsd".
   (mapped-devices (list (mapped-device
     (source "/dev/<your-encrypted-partition>")
     (target "<target-name>")
     (type luks-device-mapping))))

Moving on to the file-systems field, update these two fields:
"device", set this value to "/dev/mapper/<target-name>". Example 
"/dev/mapper/guixsd"
"title", change this value to "'device". (Makes the "device" field be 
interpreted as a file name rather than a partition label name)

*****TODO: Unencrypted /boot*****



7.1.5.2 Special configuration for unencrypted root
Skip this chapter if you're doing encrypted root.

In the file-systems field, update this field:
"device", set this value to the label you made when you created the 
filesystem. Example "my-root"



7.1.5.3 Finishing up the configuration
And finally, update the values in the "users" field.
"name", the username.
"comment", you can set this to the name of the user.
"home-directory", set this to "/home/<username>".

This concludes the updates to the configuration file and the preparation 
for installation.





7.1.6 Installation
What remains now is to actually install the system. First run this 
command to get up to speed with the project's progress since this 
installer was created.
# guix pull

Then run this command to initialize the system based on the 
configuration file you've prepared.
# guix system init /mnt/etc/config.scm /mnt

This will copy all the necessary files, and install GRUB on /dev/<disk>, 
unless you pass the --no-grub 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).

Join us on #guix on the Freenode IRC network or on address@hidden to 
share your experience—good or not so good.





ADDENDUM #1
Manual steps to boot your fully encrypted system from an embedded GRUB.
Press "c" in GRUB to enter command mode.

First find the partition here which corresponds to your /dev/<disk> from 
earlier. For example "/dev/sda1" on GPT will be "ahci0,gpt1"
# ls

Now decrypt it, <grub-partition> is the partition you found in the 
previous step. Don't use quotes.
# cryptomount <grub-partition>

Load GuixSD's GRUB configuration file
# configfile (crypto0)/boot/grub/grub.cfg





ADDENDUM #2
When you're ready to update the GRUB configuration file in your boot 
firmware you can base them off of these examples. Values to update:
"cryptomount" (there's one in both menu entries).
"--root" flag, to point to "/dev/<your-root-partition>". Example 
"/dev/mapper/guixsd".

menuentry "GuixSD (current)" {
  cryptomount <grub-partition>
  set root=(crypto0)
  set guix_system=/var/guix/profiles/system
  linux  ${guix_system}/kernel/bzImage --root=/dev/<your-root-partition> 
--system=${guix_system} --load=${guix_system}/boot
  initrd ${guix_system}/initrd
}

menuentry "GuixSD fallback" {
  cryptomount <grub-partition>
  configfile (crypto0)/boot/grub/grub.cfg
}