Add validation on sshd-config changes

roles/common/tasks/main.yaml

@@ -108,6 +108,7 @@
     path: /etc/ssh/sshd_config
     regexp: "{{ item.regexp }}"
     line: "{{ item.line }}"
+    validate: "/usr/sbin/sshd -t -f %s"
   with_items:
     - regexp: '^#?Port'
       line: 'Port {{ ssh_port }}'