Modified backup task to use the 'copy' module instead of 'shell' by p…

…assing the 'remote_src' option. This helps to enforce a desired state model and reduces ambiguity on success/failure.

tasks/main.yml

@@ -5,9 +5,11 @@
 - name: Enable Postfix
   service: name=postfix state=started enabled=yes
 
-- name: Backup configuration
-  shell: cp /etc/postfix/main.cf /etc/postfix/main.cf.{{ postfix_backup_multiple | ternary("`date -Iseconds`", "backup") }}
-  when: postfix_backup or postfix_backup_multiple
+- name: Backup configuration using copy
+  copy:
+    remote_src: yes
+    src: /etc/postfix/main.cf
+    dest: /etc/postfix/main.cf.{{ postfix_backup_multiple | ternary( lookup('pipe','date -Iseconds') , "backup") }}
 
 - name: Add header 1 to configuration file
   lineinfile: