This tool watches a volume mounted configmap directory and kubernetes events for services with annotations labeled "nordstrom.net/alerts/prometheus" for Prometheus alerting rules. If they are found they are validated and placed into two files (one for annotations and one for configmaps) then the passed enpoint is hit.

Parameters

• -cmrules - Takes a filename where you would like the configmap rules to be written
• -svrules - Takes a filename where you would like the service annotation rules to be written
• -map - Path where the configmap is mounted
• -endpoint - Endpoint to make a bodyless POST request to (Prometheus uses /-/reload)

All of these parameters will by default use the following envriomental variables:

• cmrules defaults to 'CM_RULES_LOCATION'
• svrules defaults to 'SV_RULES_LOCATION'
• map defaults to 'CONFIG_MAP_LOCATION'
• endpoint defaults to 'PROMETHEUS_RELOAD_ENDPOINT'

for example:

./PrometheusRuleLoader -cmrules ./cmrules.rules -svrules ./svrules.rules -map ./config -endpoint http://prometheus.cluster.local/-/reload

Service Annotations

The annotation supports either a json string or a json array. The annotation must have the key "nordstrom.net/alerts/prometheus"

Examples:

---
apiVersion: v1
kind: Service
metadata:
  name: fakeservice
  namespace: default
  labels:
    app: fake
  annotations: 
    nordstrom.net/prometheusAlerts: |
      - ALERT TooManyFoosTooFast
        IF sum(rate(fooCounter[1m])) > 1
        FOR 1m
        LABELS { severity = "critical" }
        ANNOTATIONS {
          description = "Rate of foo very high ({{ $value }})."
        }
      - ALERT TooManyLogsTooFast
        IF sum(rate(logCounter[1m])) > 1
        FOR 1m
        LABELS { severity = "warning" }
        ANNOTATIONS {
          description = "Rate of log very high ({{ $value }})."
        }
spec:
  ports:
    - name: foo
      port: 80
  selector:
    app: foo

Other Notes

Every rule is verified and only ones that pass are added to the configuration files. If you see a rule failing to pass you can use the promtool that ships with prometheus to verify it.