Make use of host_vars for postfix.

host_vars/boeing.adm.crans.org

@@ -0,0 +1,7 @@
+postfix:
+  primary: false
+  secondary: true
+  public: true
+  dkim: true
+  mailman: false
+  titanic: true

host_vars/sputnik.adm.crans.org.yml

@@ -0,0 +1,7 @@
+postfix:
+  primary: false
+  secondary: true
+  public: true
+  dkim: true
+  mailman: false
+  titanic: false

network.yml

@@ -190,28 +190,3 @@
       remote_as: 8218
   roles:
     - quagga-ipv6
-
-# Deploy postfix on mail servers
-- hosts: titanic.adm.crans.org
-  vars:
-    postfix:
-      primary: false
-      secondary: true
-      public: true
-      dkim: true
-      mailman: false
-      titanic: true
-  roles:
-    - postfix
-
-- hosts: sputnik.adm.crans.org
-  vars:
-    postfix:
-      primary: false
-      secondary: true
-      public: true
-      dkim: true
-      mailman: false
-      titanic: false
-  roles:
-    - postfix

postfix.yml

@@ -0,0 +1,6 @@
+#!/usr/bin/env ansible-playbook
+# Postfix playbook
+---
+- hosts: sputnik.adm.crans.org, boeing.adm.crans.org
+  roles:
+    - postfix