Added some alerting rules

prometheus-only/alert.rules.yml

@@ -9,4 +9,4 @@ groups:
       severity: page
     annotations:
       summary: "Instance {{ $labels.instance }} down"
-      description: "{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 5 minutes."
+      description: "{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 30 seconds."

prometheus-only/prometheus.yml

@@ -4,7 +4,7 @@ global:
   # Attach these labels to any time series or alerts when communicating with
   # external systems (federation, remote storage, Alertmanager).
   external_labels:
-    monitor: 'codelab-monitor'
+    monitor: 'cosee-monitor'
 
 # A scrape configuration containing exactly one endpoint to scrape:
 # Here it's Prometheus itself.
@@ -15,7 +15,7 @@ scrape_configs:
     scrape_interval: 5s
 
     static_configs:
-      - targets: ['localhost:9090']
+      - targets: ['localhost:9090', 'exporter:9100']
 
 rule_files:
   - 'alert.rules.yml'
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