Use builtin autodiscovery of alertmanager

Change-Id: I36bdb3a4e90687d32724e5e248d5862567c36f83
Depends-On: I91e23f17858deb2ef937fcd42948641eb371474b

prometheus/files/prometheus.yml

@@ -5,6 +5,25 @@ global:
 {{ server.config.global | yaml(False) | indent(2, true) }}
 {%- endif %}
 
+{%- if server.get('config', {}).get('alertmanager') %}
+alerting:
+  alertmanagers:
+    {%- for name, alertmanager in server.config.alertmanager.iteritems() %}
+    {%- if alertmanager.get('enabled', True) %}
+    # {{ name }}
+    {%- if alertmanager.static_configs is defined %}
+    - static_configs:
+      - targets: {{ alertmanager.static_configs.get('target', [])|yaml }}
+    {%- elif alertmanager.dns_sd_configs is defined %}
+    - dns_sd_configs:
+      - names: {{ alertmanager.dns_sd_configs.get('domain', [])|yaml }}
+        type: {{ alertmanager.dns_sd_configs.type }}
+        port: {{ alertmanager.dns_sd_configs.port }}
+    {%- endif %}
+    {%- endif %}
+    {%- endfor %}
+{%- endif %}
+
 rule_files:
 - alerts.yml
 

tests/pillar/server.sls

@@ -68,6 +68,14 @@ prometheus:
         evaluation_interval: "1m"
         external_labels:
           region: 'region1'
+      alertmanager:
+        docker_swarm_alertmanager:
+          enabled: true
+          dns_sd_configs:
+            domain:
+              - tasks.monitoring_alertmanager
+            type: A
+            port: 9093
 docker:
   host:
     enabled: true