Improve routing between containers

Create user network nginx-internal
and use Docker's internal DNS server
to resolve containers by hostname.

roles/nginx/tasks/main.yml

@@ -58,10 +58,18 @@
     src: nginx.conf.j2
     dest: "{{ data_folder }}/nginx/nginx.conf"
     mode: '0755'
+- name: create nginx bridge network
+  docker_network:
+    name: nginx-internal
+    attachable: true
+    internal: true
+    state: present
 - name: run container
   docker_container:
     name: 'nginx'
     image: nginx
+    networks:
+      - name: nginx-internal
     volumes:
       - "{{ data_folder }}/nginx/nginx.conf:/etc/nginx/nginx.conf"
       - "{{ data_folder }}/nginx/{{ base_domain }}.key:/etc/nginx/{{ base_domain }}.key"