Query the API to find the latest Debian image to deploy the base system with.

* gnu/machine/hetzner/http.scm (null-or): New procedure.
(<hetzner-image>): New JSON record type.
(<hetzner-image-created-from>): Likewise.
(<hetzner-image-protection>): Likewise.
(%hetzner-default-server-image): Change simple variable to a memoized
procedure.
(hetzner-api-server-create): Adjust user accordingly.
(hetzner-api-images): New procedure.

Change-Id: I9544708c878971a2c776c80b9a4ee06078d5ce61

This fixes a regression introduced in commit a2ef2bcbfd7 ("machine: hetzner:
Allow connections using ssh-agent"), where having no ssh-key would cause the
early Hetzner provisioning to fail due to the lack of SSH authentication.

* gnu/machine/hetzner.scm (%hetzner-ssh-key-file): New parameter.
(<hetzner-configuration>) [ssh-public-key]: Compute default according to the
value of the private ssh-key field.  Introduce an indirection via...
(hetzner-configuration-ssh-public-key): ... this new procedure, to honor
%hetzner-ssh-key-file.
(hetzner-configuration-ssh-key): Likewise for the private ssh-key.
(hetzner-configuration-ssh-key-fingerprint): Rename to...
(public-key->fingerprint): ... this, taking just the public key as argument.
Update doc.
(hetzner-configuration-ssh-key-public): Rename to...
(public-key->string-with-type): ...this, for clarity, and accept just a
public-key object.  Update doc.
(hetzner-machine-ssh-key): Exit early with #f when no ssh key is provided.
(temporary-ssh-key-file): New procedure.
(hetzner-machine-ssh-key-create): Assert a public key is defined.  Adjust
calls to renamed procedures, and adjust for the `hetzner-api-server-create'
API change.
(hetzner-machine-enable-rescue-system): Refine doc and fix code path when
ssh-key is #f.
(hetzner-machine-rescue-install-os): Document.
(hetzner-machine-provision): Refine doc. Remove extraneous sleep and #:unwind
argument. Limit ssh-session dynamic scope to where it's needed.
(cleanup-temporary-ssh-key/maybe): New procedure.
(deploy-hetzner): Create and use a temporary SSH key when none is defined, and
clean it up when done or on errors.
* gnu/machine/hetzner/http.scm (hetzner-api-server-create): Make ssh-keys a
keyword argument, and fix execution when it's #f.
(hetzner-api-server-enable-rescue-system): Likewise.
* tests/machine/hetzner.scm ("deploy-machine-mock-with-unprovisioned-server"):
Adjust test.
* tests/machine/hetzner/http.scm (create-server)
("hetzner-api-server-create-unit")
("hetzner-api-server-enable-rescue-system-unit")
("hetzner-api-actions-integration")
("hetzner-api-server-enable-rescue-system-integration"): Likewise.
* doc/guix.texi (Invoking guix deploy): Precise what happens when 'ssh-key' is
 #f in hetzner-configuration, and suggest declaratively authorizing your SSH
key.

Change-Id: I812b348fb553f3b5aebd0bf66850c6ecb9e06653

* gnu/machine/hetzner.scm (<hetzner-configuration>)
[user]: New field.
(hetzner-machine-delegate): Use match-record to bind the field values; honor
user.
* doc/guix.texi (Invoking guix deploy): Document it.

Fixes: #8493
Change-Id: I026828c508ea936523fe864e2646ab9e3a1329c4

All the performance and general purpose newer x86 Hetzner server types like
the 'cpx22' now require an EFI bootloader, while older ones like the 'cx23'
still expect a BIOS bootloader.

Instead of exposing the user to errors when selecting the correct operating
system template to use, provide a procedure that takes returning one based on
the server type name.

* gnu/machine/hetzner.scm (%hetzner-os-arm): Rename to...
(%hetzner-os-arm/efi): ... this.  Adjust for variable name change.
(%hetzner-os-x86): Rename to...
(%hetzner-os-x86/bios): ... this.  Adjust for variable name change.
(%hetzner-os-x86/efi): New variable.
(server-type-name->arch, server-type-name->bootloader)
(make-hetzner-os): New procedures.
(%hetzner-os-x86, %hetzner-os-x86): Deprecate variables.
(hetzner-machine-bootstrap-os-form): Use the server type name to infer whether
the EFI or BIOS bootloader should be used, along the EFI partition.
* doc/guix.texi (Invoking guix deploy): Updated doc.

Fixes: #8523
Change-Id: I331a76e12bb3c19f5664dcbe4437a8d1cfe1d363

This reverts commit 3e1befe1d8e ("machine: hetzner: Fix deployment."),
adopting a simpler/correct alternative.

* gnu/machine/hetzner.scm (hetzner-machine-rescue-install-os): Bind mount
/gnu, not /gnu/store.

Change-Id: I09ffb4db8a39b4bcd5e7645aee63427c6bc969a0
Suggested-by: Rutherther <rutherther@ditigal.xyz>

Guix 1.5.0 supports dhcpcd-service-type; therefore, (assuming hetzner
already has a Guix 1.5.0 image), it should no longer be necessary to
use dhcp-client-service-type here.  This is one of the few remaining
users of dhcp-client-service-type changing this here will allow to
remove this deprecated service in a future pull request.

* gnu/machine/hetzner.scm (hetzner-machine-bootstrap-os-form): Use
dhcpcd-service-type.

Signed-off-by: Maxim Cournoyer <maxim@guixotic.coop>

 #f is to keep the failed provisioned server intact for debugging. The
documented default is #t, so adjust the code accordingly.

* gnu/machine/hetzner.scm (<hetzner-configuration>)
[delete?]: Change default to #t to match documentation.

Change-Id: Iabee105cbf5f5e31e8a8f5cb5db99439a168f174

* gnu/machine/hetzner.scm (hetzner)
[hetzner-machine-rescue-install-os]: Fix deployment.

Reported-by: Sylvain Bellemare (https://codeberg.org/gluonix)
Fixes: #6585
Change-Id: Ie16ee541ad5b81d5014b825ad0e35deddd2e497e
Signed-off-by: Maxim Cournoyer <maxim@guixotic.coop>

* gnu/machine/hetzner.scm (operating-system-authorize): Refer to ‘services’
instead of calling ‘operating-system-user-services’.
* gnu/services/virtualization.scm (secret-service-operating-system): Likewise.
* gnu/tests.scm (operating-system-with-console-syslog): Likewise.
* gnu/tests/avahi.scm (%avahi-os): Likewise.
* gnu/tests/base.scm (%test-guix-daemon-unprivileged): Likewise.
* gnu/tests/nfs.scm (%nfs-os): Likewise.
(run-nfs-full-test): Likewise.
* gnu/system/vm.scm (virtualized-operating-system): Refer to ‘initrd-modules’
instead of calling ‘operating-system-initrd-modules’.

Change-Id: I00c5f5c1e171b174bf0ca709b2dbd13a2fe161b5

* gnu/machine/hetzner.scm (hetzner-machine-rescue-install-packages): Install
uidmap package too.

Change-Id: I86f638bc65d42cb4e26381cd91140cd92bc90b18
Signed-off-by: Ludovic Courtès <ludo@gnu.org>