Index: etc/icinga2/conf.d/hosts.conf
--- etc/icinga2/conf.d/hosts.conf.orig
+++ etc/icinga2/conf.d/hosts.conf
@@ -24,7 +24,7 @@ object Host NodeName {
   address6 = "::1"
 
   /* Set custom variable `os` for hostgroup assignment in `groups.conf`. */
-  vars.os = "Linux"
+  vars.os = "OpenBSD"
 
   /* Define http vhost attributes for service apply rules in `services.conf`. */
   vars.http_vhosts["http"] = {
