machine: hetzner: Introduce the `make-hetzner-os' procedure.

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

2 files changed, 99 insertions, 51 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 67c81ebe836..9df177d13ae 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -49,7 +49,7 @@ Copyright @copyright{} 2017 humanitiesNerd@*
 Copyright @copyright{} 2017, 2021 Christine Lemmer-Webber@*
 Copyright @copyright{} 2017, 2018, 2019, 2020, 2021, 2022 Marius Bakke@*
 Copyright @copyright{} 2017, 2019, 2020, 2022 Hartmut Goebel@*
-Copyright @copyright{} 2017, 2019--2025 Maxim Cournoyer@*
+Copyright @copyright{} 2017, 2019--2026 Maxim Cournoyer@*
 Copyright @copyright{} 2017–2022 Tobias Geerinckx-Rice@*
 Copyright @copyright{} 2017 George Clemmer@*
 Copyright @copyright{} 2017 Andy Wingo@*
@@ -50528,36 +50528,36 @@ server.
 Once the server has been provisioned and SSH is available, deployment
 continues by delegating it to the @code{managed-host-environment-type}.
 
-Servers on the Hetzner Cloud service can be provisioned on the AArch64
-architecture using UEFI boot mode, or on the x86_64 architecture using
-BIOS boot mode.  The @code{(gnu machine hetzner)} module exports the
-@code{%hetzner-os-arm} and @code{%hetzner-os-x86} operating systems that
-are compatible with those two architectures, and can be used as a base
-for defining your custom operating system.
+Depending on their type, x86_64 or AArch64 servers on the Hetzner Cloud
+service can be provisioned using BIOS or UEFI boot mode.  The @code{(gnu
+machine hetzner)} module exports the @code{make-hetzner-os} procedure,
+which takes the server type string as an argument (e.g. @code{"cx23"})
+and returns a base @code{operating-system} definition compatible with
+it.
 
 The following example shows the definition of two machines that are
-deployed on the Hetzner Cloud service.  The first one uses the
-@code{%hetzner-os-arm} operating system to run a server with 16 shared
-vCPUs and 32 GB of RAM on the @code{aarch64} architecture, the second
-one uses the @code{%hetzner-os-x86} operating system on a server with 16
-shared vCPUs and 32 GB of RAM on the @code{x86_64} architecture.
+deployed on the Hetzner Cloud service.  The first one for an ARM server
+type that has 16 shared vCPUs and 32 GB of RAM, the second for an x86_64
+server type that has 16 shared vCPUs and 32 GB of RAM.
 
 @lisp
 (use-modules (gnu machine)
              (gnu machine hetzner))
 
-(list (machine
-       (operating-system %hetzner-os-arm)
-       (environment hetzner-environment-type)
-       (configuration (hetzner-configuration
-                       (server-type "cax41")
-                       (ssh-key "/home/charlie/.ssh/id_rsa"))))
-      (machine
-       (operating-system %hetzner-os-x86)
-       (environment hetzner-environment-type)
-       (configuration (hetzner-configuration
-                       (server-type "cpx51")
-                       (ssh-public-key "/home/charlie/.ssh/id_rsa.pub")))))
+(list (let ((server-type "cax41"))
+        (machine
+          (operating-system (make-hetzner-os server-type))
+          (environment hetzner-environment-type)
+          (configuration (hetzner-configuration
+                           (server-type server-type)
+                           (ssh-key "/home/charlie/.ssh/id_rsa")))))
+      (let ((server-type "cpx51"))
+        (machine
+          (operating-system (make-hetzner-os server-type))
+          (environment hetzner-environment-type)
+          (configuration (hetzner-configuration
+                           (server-type server-type)
+                           (ssh-public-key "/home/charlie/.ssh/id_rsa.pub"))))))
 @end lisp
 
 @vindex GUIX_HETZNER_API_TOKEN
diff --git a/gnu/machine/hetzner.scm b/gnu/machine/hetzner.scm
index 8795ff8e5ea..07e62d24e33 100644
--- a/gnu/machine/hetzner.scm
+++ b/gnu/machine/hetzner.scm
@@ -36,6 +36,7 @@
   #:use-module (gnu system)
   #:use-module (guix base32)
   #:use-module (guix colors)
+  #:use-module (guix deprecation)
   #:use-module (guix derivations)
   #:use-module (guix diagnostics)
   #:use-module (guix gexp)
@@ -66,8 +67,10 @@
   #:use-module (ssh session)
   #:use-module (ssh sftp)
   #:use-module (ssh shell)
-  #:export (%hetzner-os-arm
-            %hetzner-os-x86
+  #:export (%hetzner-os-arm             ;deprecated
+            %hetzner-os-x86             ;deprecated
+            make-hetzner-os
+
             deploy-hetzner
             hetzner-configuration
             hetzner-configuration-allow-downgrades?
@@ -98,7 +101,7 @@
 
 ;; Operating system for arm servers using UEFI boot mode.
 
-(define %hetzner-os-arm
+(define %hetzner-os-arm/efi
   (operating-system
     (host-name "guix-arm")
     (bootloader
@@ -128,9 +131,9 @@
 
 ;; Operating system for x86 servers using BIOS boot mode.
 
-(define %hetzner-os-x86
+(define %hetzner-os-x86/bios
   (operating-system
-    (inherit %hetzner-os-arm)
+    (inherit %hetzner-os-arm/efi)
     (host-name "guix-x86")
     (bootloader
      (bootloader-configuration
@@ -146,6 +149,51 @@
              (type "ext4"))
            %base-file-systems))))
 
+(define %hetzner-os-x86/efi
+  (operating-system
+    (inherit %hetzner-os-arm/efi)
+    (host-name "guix-x86")
+    (initrd-modules
+     (cons "virtio_scsi" %base-initrd-modules))))
+
+(define (server-type-name->arch type-name)
+  "Return a symbol corresponding to the server type architecture, e.g.
+@code{'x86} or @code{'arm}."
+  (cond
+    ((string-prefix-ci? "cax" type-name)
+     'arm)
+    (else
+     'x86)))
+
+(define (server-type-name->bootloader type-name)
+  "Return a symbol corresponding to the bootloader type, e.g.
+@code{'efi} or @code{'bios}."
+  (if (eq? 'arm (server-type-name->arch type-name))
+      'efi
+      (cond
+       ((string-prefix-ci? "cx" type-name)
+        'bios)                          ;old, cost-optimized x86 servers
+       (else
+        'efi))))           ;newer, regular performance/general purpose servers
+
+(define* (make-hetzner-os server-type-name)
+  "Return an operating server customized for SERVER-TYPE-NAME, a string like
+\"cx23\" or \"cax11\", denoting the Hetzner virtual server type."
+  (match (server-type-name->arch server-type-name)
+    ('arm %hetzner-os-arm/efi)
+    ('x86
+     (match (server-type-name->bootloader server-type-name)
+       ('bios %hetzner-os-x86/bios)
+       ('efi %hetzner-os-x86/efi)))))
+
+(define-deprecated %hetzner-os-x86
+  make-hetzner-os
+  %hetzner-os-x86/bios)
+
+(define-deprecated %hetzner-os-arm
+  make-hetzner-os
+  %hetzner-os-arm/efi)
+
 (define (operating-system-authorize os)
   "Authorize the OS with the public signing key of the current machine."
   (if (file-exists? %public-key-file)
@@ -363,43 +411,43 @@ Available locations:~%~%~a~%~%For more details, see: ~a")
   "Return the form to bootstrap an operating system on SERVER."
   (let* ((os (machine-operating-system machine))
          (system (hetzner-server-system server))
+         (type-name (hetzner-server-type-name (hetzner-server-type server)))
          (arm? (equal? "arm" (hetzner-server-architecture server)))
          (x86? (equal? "x86" (hetzner-server-architecture server)))
+         (efi? (equal? 'efi (server-type-name->bootloader type-name)))
          (root-fs-type (operating-system-root-file-system-type os)))
     `(operating-system
        (host-name ,(operating-system-host-name os))
        (timezone "Etc/UTC")
        (bootloader (bootloader-configuration
-                    (bootloader ,(cond (arm? 'grub-efi-bootloader)
-                                       (x86? 'grub-bootloader)))
-                    (targets ,(cond (arm? '(list "/boot/efi"))
-                                    (x86? '(list "/dev/sda"))))
-                    (terminal-outputs '(console))))
+                     (bootloader ,(if efi?
+                                      'grub-efi-bootloader
+                                      'grub-bootloader))
+                     (targets ,(if efi?
+                                   '(list "/boot/efi")
+                                   '(list "/dev/sda")))
+                     (terminal-outputs '(console))))
        (initrd-modules (append
                         ,(cond (arm? '(list "sd_mod" "virtio_scsi"))
                                (x86? '(list "virtio_scsi")))
                         %base-initrd-modules))
-       (file-systems ,(cond
-                       (arm? `(cons* (file-system
-                                       (mount-point "/")
-                                       (device "/dev/sda1")
-                                       (type ,root-fs-type))
-                                     (file-system
-                                       (mount-point "/boot/efi")
-                                       (device "/dev/sda15")
-                                       (type "vfat"))
-                                     %base-file-systems))
-                       (x86? `(cons* (file-system
-                                       (mount-point "/")
-                                       (device "/dev/sda1")
-                                       (type ,root-fs-type))
-                                     %base-file-systems))))
+       (file-systems (cons* (file-system
+                              (mount-point "/")
+                              (device "/dev/sda1")
+                              (type ,root-fs-type))
+                            ,@(if efi?
+                                  '((file-system
+                                      (mount-point "/boot/efi")
+                                      (device "/dev/sda15")
+                                      (type "vfat")))
+                                  '())
+                            %base-file-systems))
        (services
         (cons* (service dhcpcd-service-type)
                (service openssh-service-type
                         (openssh-configuration
-                         (openssh openssh-sans-x)
-                         (permit-root-login 'prohibit-password)))
+                          (openssh openssh-sans-x)
+                          (permit-root-login 'prohibit-password)))
                %base-services)))))
 
 (define (rexec-verbose session cmd)