guix deploy: modinfo.sh doesn't exist error

[Dmitry Matveyev]

I'm trying to use guix deploy to install a Guix System at vultr.com
using a minimal iso image file of Guix System. So I do:

1. Create a minimal ISO image using guix system
2. Boot the ISO image on a remote server
3. Use guix deploy to install the system

I fail at step 3 with "modinfo.sh doesn't exist" error. Below is (1) the
end of the guix deploy command output and (2) my complete instruction of
what I do up to guix deploy command.

I use Guix version d6f1b9487da3e6f9c3ef49dea9c97c0408a25777 on Arch Linux.

The end of guix deploy command is:

================================================================================
building /gnu/store/m6vv3zqf792spnc9fmsnbbfah1cyjx35-grub.cfg.drv...
building 
/gnu/store/sw9rqrsdqlz5mqxji9wk7i7v30q6mgl2-install-bootloader.scm.drv...
building /gnu/store/nyb01ypw9wbhvk1yqzgpd1brydc15llq-remote-exp.scm.drv...
guix deploy: sending 3 store items (0 MiB) to '10.10.255.50'...

guix deploy: error: failed to deploy vm: failed to install bootloader on
'70.34.254.49':

%exception #<inferior-object #<&message message:
"'/gnu/store/ch9q9w5zbvgq8srr6dscq6hdf03pfqb4-grub-efi-2.06/sbin/grub-install
--boot-directory //boot --bootloader-id=Guix --efi-directory/boot/efi'
exited with status 1; output follows:\n\n
/gnu/store/ch9q9w5zbvgq8srr6dscq6hdf03pfqb4-grub-efi-2.06/sbin/grub-install:
error:
/gnu/store/ch9q9w5zbvgq8srr6dscq6hdf03pfqb4-grub-efi-2.06/lib/grub/i386-pc/modinfo.sh
doesn't exist. Please specify --target or --directory.\n">>
================================================================================


The complete instruction of my current deployment process:

================================================================================
# How to set up Guix System on VPS

## Preparation

We need to have basic things for setting up.

1. Set up DNS record for future HTTPS support, for example, on
   <https://porkbun.com>.

2. Register at the hosting provider site, for example, on <https://vultr.com>.

3. If not using the Guix System as your desktop operating system, install Guix
   on your system as a package manager
   <https://guix.gnu.org/manual/en/html_node/Installation.html>.

## Create and deploy the first image

1. Create a new directory for this deployment and `cd` there.

2. Generate ssh keys for authentication: run `ssh-keygen`, choose to store them
   in the current directory `./`.

3. Copy this to `base_vm.scm`

``` scm
(use-modules (gnu))
(use-service-modules networking ssh)
(use-package-modules bootloaders ssh)

(operating-system
 (host-name "vm")
 (locale "en_US.utf8")
 (timezone "Etc/UTC")
 (bootloader (bootloader-configuration
              (bootloader grub-bootloader)
              (targets '("/dev/vda"))
              (terminal-outputs '(console))))
 (file-systems (cons (file-system
                      (mount-point "/")
                      (device "/dev/vda1")
                      (type "ext4"))
                     %base-file-systems))
 (services
  (append (list (service dhcp-client-service-type)
                (service openssh-service-type
                         (openssh-configuration
                          (openssh openssh-sans-x)
                          (password-authentication? #f)
                          (permit-root-login #t)
                          (authorized-keys
                           ;; Authorise our SSH key.
                           `(("root" ,(local-file "id_rsa.pub")))))))
          %base-services)))
```

4. Use a minimal config in `base_vm.scm` to generate the base image of the
   operating system, this will take a while on the very first run. Note that you
   might need to change `--image-type` to something else like `qcow2` if the
   hosting provider only supports limited options. See all available formats
   with `guix system --list-image-types`.

```
guix system image --save-provenance --image-type=iso9660 base_vm.scm
```

At the very end there will be a path to the generated image such as

```
/gnu/store/6ab54m88rfbdankmacrgpcm9gzzbmi1v-image.iso
```

5. Upload this image to the hosting provider. In Vultr it is required to put it
   online, for example, to <https://dropbox.com> as it allows 2 GB free
   space. Only then it can be added as an iso image in a separate step.

6. Choose options for the virtual server, select the uploaded image and
   instantiate the system.

7. Try logging in with ssh, for example:

```
ssh -i id_rsa root@10.10.142.48
```

8. If booted from iso on Vultr, it is necessary to partition the disk too:

``` shell
fdisk /dev/vda

# Create new GPT table
g

# Create partition for /boot, set size to 300 MB and change its type to UEFI
n
+300M
t
uefi

# Create partition for root partition for all the remaining space
n
# Press Enter many times
t
2
# This is "Linux root (x86-64)
4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709

# Check that everything is good
p

# Write partitions and quit
w
```

9. If everything is successful, quit with Ctrl+D.

10. Generate Guix signing keys with `sudo guix archive --generate-key`, now they
    are available at `/etc/guix`.

11. Save this template to `first_deploy.scm`:

```scm
(use-modules (gnu) (guix))
(use-service-modules networking ssh admin)
(use-package-modules bootloaders ssh)

(define os
  (operating-system
    (host-name "vm")
    (locale "en_US.utf8")
    (timezone "Etc/UTC")
    (bootloader (bootloader-configuration
                 (bootloader grub-efi-bootloader)
                 (targets '("/boot/efi"))))
    (file-systems (append
                   (list (file-system
                          (device "/dev/vda2")
                          (mount-point "/")
                          (type "ext4"))
                         (file-system
                          (device "/dev/vda1")
                          (mount-point "/boot/efi")
                          (type "vfat")))
                   %base-file-systems))
    (services
     (append
      (list (service openssh-service-type
                     (openssh-configuration
                      (openssh openssh-sans-x)
                      (password-authentication? #f)
                      (permit-root-login #t)
                      (authorized-keys
                       `(("root" ,(local-file "id_rsa.pub"))))))
            (service dhcp-client-service-type)
            (service unattended-upgrade-service-type))
      (modify-services %base-services
                       ;; The server must trust the Guix packages you build. If 
you add the signing-key
                       ;; manually it will be overridden on next `guix deploy` 
giving
                       ;; "error: unauthorized public key". This automatically 
adds the signing-key.
                       (guix-service-type config =>
                                          (guix-configuration
                                           (inherit config)
                                           (authorized-keys
                                            (append (list (local-file 
"/etc/guix/signing-key.pub"))
                                                    
%default-authorized-guix-keys)))))))))

(list (machine
       (operating-system os)
       (environment managed-host-environment-type)
       (configuration (machine-ssh-configuration
                       (host-name "71.41.243.84")
                       (system "x86_64-linux")
                       ;; Update this after seeing an error running `guix 
deploy`.
                       (host-key "ssh-ed25519 
AAAAC3N123456789mZwG+Y8Xk+XN123456789GNJ1RU3BkuUU")
                       (user "root")
                       ;; Use this key to communicate with the machine.
                       (identity "id_rsa")))))
```

12. Try deploying with `guix deploy first_deploy.scm`, you will see an error 
that
    host key doesn't match, it is expected, update it in the machine
    configuration accordingly:

```
(host-key "ssh-ed25519 AAAAC3N123456789mZwG+Y8Xk+XN123456789GNJ1RU3BkuUU")
```

13. Re-run `guix deploy first_deploy.scm` to finally install the system. Note
    that you may need to run it several times in case it fails because of errors
    such as "Throw to key `guile-ssh-error' with args `("channel-open-session"
    "Channel openingfailure: channel 67 error (2) open failed" #<input-output:
    channel (closed) 7f96971b8760> #f)'" - this is probably a transient error,
    see discussion at <https://issues.guix.gnu.org/56709>.

## References

- <https://guix.gnu.org/blog/2019/managing-servers-with-gnu-guix-a-tutorial/> -
  blog post on Guix
- <https://othacehe.org/hosting-a-blog-using-only-scheme.html> - deploying a
  blog
- <https://stumbles.id.au/getting-started-with-guix-deploy.html> - deploying on
  Digital Ocean Guix->Guix
- <https://wiki.pantherx.org/Installation-digital-ocean/> - deploying on Digital
  Debian->Guix
- <https://paste.sr.ht/~akagi/04c11305b19b1b25d0e61a88f6892057dee01b67> -
  example config
================================================================================

Best,
Dmitry.