diff --git a/modules/oms/systems.scm b/modules/oms/systems.scm
index 9739c64..65f6554 100644
--- a/modules/oms/systems.scm
+++ b/modules/oms/systems.scm
@@ -1,6 +1,7 @@
 (define-module (oms systems)
   #:use-module (gnu)
   #:use-module (gnu packages cups)
+  #:use-module (gnu services admin)
   #:use-module (gnu services base)
   #:use-module (gnu services cups)
   #:use-module (gnu services desktop)
@@ -94,3 +95,38 @@
                      (options "size=70%")
                      (create-mount-point? #t)))
              %base-file-systems))))
+
+(define-syntax-rule (define-system id os)
+  "Extend the operating system OS with unattended upgrades and define a varible
+ID with the extended system as it's value."
+  (define-public id
+    (let ((base os))
+      (operating-system
+        (inherit base)
+        (services
+         (append
+          (list (service unattended-upgrade-service-type
+                         (unattended-upgrade-configuration
+                           (channels
+                            #~(cons (channel
+                                      (name 'oms-tietokoneet)
+                                      (url "https://git.olarinmaensamoojat.fi/OMS/tietokoneet.git")
+                                      (branch "main")
+                                      (introduction
+                                       (make-channel-introduction
+                                        "a3665902d411cd473636a836c2efd707b3a25cfd"
+                                        (openpgp-fingerprint
+                                         "A0C9 1947 734F 076F 5F08 E9FF 257D 284A 2A1D 3A32"))))
+                                    %default-channels))
+                           (operating-system-expression
+                            #~(@ (oms systems) id)))))
+          (operating-system-user-services base)))))))
+
+(define-system oms-morn (base-operating-system "OMS-morn"))
+
+(define-system oms-celeb
+  (let ((base (base-operating-system "OMS-celeb")))
+    (operating-system
+      (inherit base)
+      (initrd-modules
+       (append '("vmd") (operating-system-initrd-modules base))))))