add unbound-exporter setup tasks and some docs

deploy.yaml

@@ -59,6 +59,19 @@
       loop:
         - local-data.conf
         - noc.conf
+
+    # Unbound exporter installed with go as the unbound_exporter user using:
+    # go install github.com/letsencrypt/unbound_exporter@latest
+    # to /home/unbound_exporter/go/unbound_exporter
+    - name: deploy unbound exporter service
+      ansible.builtin.copy:
+        src: "resources/resolv-dns/files/unbound-exporter.service"
+        dest: "/etc/systemd/system/unbound-exporter.service"
+        owner: root
+        group: root
+        mode: "0644"
+      become: true
+      notify: Restart Unbound exporter service
       
   handlers:
     - name: Restart Unbound
@@ -66,3 +79,10 @@
         name: unbound
         state: restarted
       become: true
+
+    - name: Restart Unbound exporter service
+      ansible.builtin.systemd_service:
+        name: unbound-exporter
+        state: restarted
+        daemon_reload: true
+      become: true

resources/resolv-dns/files/unbound-exporter.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=Prometheus exporter for Unbound metrics, written in Go with pluggable metric collectors. The metrics exporter converts Unbound metric names to Prometheus metric names and labels by using a set of regular expressions.
+Documentation=https://github.com/letsencrypt/unbound_exporter
+After=network.target
+
+[Service]
+Type=simple
+ExecStart=/home/unbound_exporter/go/bin/unbound_exporter \
+    -unbound.ca "" \
+    -unbound.cert "" \
+    -unbound.key "" \
+    -unbound.host "unix:///run/unbound.ctl"
+User=unbound_exporter
+Group=unbound
+
+[Install]
+WantedBy=multi-user.target