services: Add keepalived service.

* gnu/services/networking.scm (<keepalived-configuration>): New record.
(keepalived-shepherd-service): New procedure.
(keepalived-service-type): New variable.
* doc/guix.texi (Networking Services): Document this.

doc/guix.texi

@@ -55,7 +55,7 @@ Copyright @copyright{} 2017 Andy Wingo@*
 Copyright @copyright{} 2017, 2018, 2019, 2020 Arun Isaac@*
 Copyright @copyright{} 2017 nee@*
 Copyright @copyright{} 2018 Rutger Helling@*
-Copyright @copyright{} 2018 Oleg Pykhalov@*
+Copyright @copyright{} 2018, 2021 Oleg Pykhalov@*
 Copyright @copyright{} 2018 Mike Gerwitz@*
 Copyright @copyright{} 2018 Pierre-Antoine Rouby@*
 Copyright @copyright{} 2018, 2019 Gábor Boskovits@*
@@ -17207,6 +17207,58 @@ address, delete everything except these options:
 @end table
 @end deftp
 
+@cindex keepalived
+@deffn {Scheme Variable} keepalived-service-type
+This is the type for the @uref{https://www.keepalived.org/, Keepalived}
+routing software, @command{keepalived}.  Its value must be an
+@code{keepalived-configuration} record as in this example for master
+machine:
+
+@lisp
+(service keepalived-service-type
+         (keepalived-configuration
+           (config-file (local-file "keepalived-master.conf"))))
+@end lisp
+
+where @file{keepalived-master.conf}:
+
+@example
+vrrp_instance my-group @{
+  state MASTER
+  interface enp9s0
+  virtual_router_id 100
+  priority 100
+  unicast_peer @{ 10.0.0.2 @}
+  virtual_ipaddress @{
+    10.0.0.4/24
+  @}
+@}
+@end example
+
+and for backup machine:
+
+@lisp
+(service keepalived-service-type
+         (keepalived-configuration
+          (config-file (local-file "keepalived-backup.conf"))))
+@end lisp
+
+where @file{keepalived-backup.conf}:
+
+@example
+vrrp_instance my-group @{
+  state BACKUP
+  interface enp9s0
+  virtual_router_id 100
+  priority 99
+  unicast_peer @{ 10.0.0.3 @}
+  virtual_ipaddress @{
+    10.0.0.4/24
+  @}
+@}
+@end example
+@end deffn
+
 @node Unattended Upgrades
 @subsection Unattended Upgrades
 

gnu/services/networking.scm

@@ -14,6 +14,7 @@
 ;;; Copyright © 2019 Sou Bunnbu <iyzsong@member.fsf.org>
 ;;; Copyright © 2019 Alex Griffin <a@ajgrf.com>
 ;;; Copyright © 2020 Brice Waegeneire <brice@waegenei.re>
+;;; Copyright © 2021 Oleg Pykhalov <go.wigust@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -42,6 +43,7 @@
   #:use-module (gnu packages admin)
   #:use-module (gnu packages base)
   #:use-module (gnu packages bash)
+  #:use-module (gnu packages cluster)
   #:use-module (gnu packages connman)
   #:use-module (gnu packages freedesktop)
   #:use-module (gnu packages linux)
@@ -192,7 +194,11 @@
             yggdrasil-configuration-log-level
             yggdrasil-configuration-log-to
             yggdrasil-configuration-json-config
-            yggdrasil-configuration-package))
+            yggdrasil-configuration-package
+
+            keepalived-configuration
+            keepalived-configuration?
+            keepalived-service-type))
 
 ;;; Commentary:
 ;;;
@@ -1865,4 +1871,43 @@ See yggdrasil -genconf for config options.")
           (service-extension profile-service-type
                              (compose list yggdrasil-configuration-package))))))
 
+
+;;;
+;;; Keepalived
+;;;
+
+(define-record-type* <keepalived-configuration>
+  keepalived-configuration make-keepalived-configuration
+  keepalived-configuration?
+  (keepalived  keepalived-configuration-keepalived  ;<package>
+               (default keepalived))
+  (config-file keepalived-configuration-config-file ;file-like
+               (default #f)))
+
+(define keepalived-shepherd-service
+  (match-lambda
+    (($ <keepalived-configuration> keepalived config-file)
+     (list
+      (shepherd-service
+       (provision '(keepalived))
+       (documentation "Run keepalived.")
+       (requirement '(loopback))
+       (start #~(make-forkexec-constructor
+                 (list (string-append #$keepalived "/sbin/keepalived")
+                       "--dont-fork" "--log-console" "--log-detail"
+                       "--pid=/var/run/keepalived.pid"
+                       (string-append "--use-file=" #$config-file))
+                 #:pid-file "/var/run/keepalived.pid"
+                 #:log-file "/var/log/keepalived.log"))
+       (respawn? #f)
+       (stop #~(make-kill-destructor)))))))
+
+(define keepalived-service-type
+  (service-type (name 'keepalived)
+                (extensions (list (service-extension shepherd-root-service-type
+                                                     keepalived-shepherd-service)))
+                (description
+                 "Run @uref{https://www.keepalived.org/, Keepalived}
+routing software.")))
+
 ;;; networking.scm ends here