opensmtpd: configure root mail alias

And add a README.

roles/opensmtpd/README.md

@@ -0,0 +1,3 @@
+Install opensmtpd and configure it for sending local mail through a relay.
+
+The NetBox configuration context must define `mail_relay` with the relay hostname and `mail_root` with the email address where mail for root should be forwarded.

roles/opensmtpd/handlers/main.yml

@@ -1,5 +1,5 @@
 - name: restart smtpd
   service:
-    name: smtpd
+    name: "{% if ansible_os_family == 'Alpine' %}smtpd{% else %}opensmtpd{% endif %}"
     state: restarted
   when: "'handler' not in ansible_skip_tags"

roles/opensmtpd/tasks/main.yml

@@ -1,17 +1,40 @@
-# this role is currently for alpine linux only
-
 - name: Install mail server
   package:
     name: opensmtpd
 
+# Alpine puts its configuration in /etc/smtpd, Debian in /etc
+- when: ansible_os_family == 'Debian'
+  block:
+    - name: Create configuration directory
+      file:
+        path: /etc/smtpd
+        state: directory
+
+    - name: Link configuration
+      file:
+        path: "/etc/smtpd/{{ item }}"
+        src: "/etc/{{ item }}"
+        state: link
+      loop:
+        - smtpd.conf
+        - aliases
+      notify: restart smtpd
+
 - name: Configure mail server
   template:
     dest: /etc/smtpd/smtpd.conf
     src: smtpd.conf.j2
+    follow: true
   notify: restart smtpd
 
+- name: Configure root mail alias
+  lineinfile:
+    path: /etc/smtpd/aliases
+    regexp: "^#? *root:"
+    line: "root: {{ mail_root }}"
+
 - name: Enable mail server
   service:
-    name: smtpd
+    name: "{% if ansible_os_family == 'Alpine' %}smtpd{% else %}opensmtpd{% endif %}"
     enabled: yes
     state: started