extend existing certificate list instead of overwriting it. Ansible realy needs a deep merge...

tasks/main.yml

@@ -1,4 +1,14 @@
 ---
+- set_fact:
+    nginx_certs: "{{ nginx.vhosts|nginx_vhosts_to_certificates }}"
+    inventory_certs: "{{ certificates.certs|d({}) }}"
+
+- include_role:
+    name: certificates
+  vars:
+    certificates:
+      certs: "{{ {}|combine(nginx_certs, inventory_certs, recursive=True) }}"
+
 - name: install nginx
   apt: pkg=nginx
   notify: