All standalone playbook need iptables thus install it in shared.

Cleanup unused and not working packages installations (socat)

playbook/roles/standalone-shared/tasks/main.yml

 ---
   - include: debian9-gcc-4.9.yml
+ 
+  - name: Install iptables
+    apt:
+      pkg:
+        - iptables
+      state: present
 
   - name: Store domain for other scripts
     copy: content="{{ frontend_custom_domain }}" dest=/tmp/playbook-frontend-custom-domain mode=0644

playbook/wendelin-standalone-test.yml

@@ -11,5 +11,3 @@
     playbook_name: wendelin
   roles:
     - standalone-shared
-    - { role: package, package_name: socat, package_state: present }
-    - { role: package, package_name: iptables, package_state: present }