Integrate arangodb-exporter

[ewoutp]

In order to export arangodb metrics to Prometheus, the operator should be extended to run an arangodb-exporter sidecar container for every arangod(agent|dbserver|coordinator|single) Pod.

This involves:

• Adding an option to the DeploymentSpec to turn on/off exporting metrics
• If enabled, add a container running arangodb-exporter for every arangod pod.
  Follow the template spec in the Deployment example below.
• Add a Service that selects all exporters of the deployment.
• Add a ServiceMonitor that adds the arangodb-exporters as target in Prometheus.

See arangodb-helper/arangodb-exporter#4 for using the exporter with the Prometheus Operator.

Below is an example of (manually) running the exporter for 1 agent (that was deployed by the operator).

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: arangodb-export-agent1
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: arangodb-exporter
    spec:
      containers:
      - name: exporter
        image: arangodb/arangodb-exporter:0.1.3
        ports:
        - name: metrics
          containerPort: 9101
        args:
        - --arangodb.endpoint=ssl://example-simple-cluster-agent-0mmwt80z.example-simple-cluster-int.default.svc:8529
        - --arangodb.jwtsecret=$(ARANGOD_JWT_SECRET)
        - --ssl.keyfile=/secrets/tls/tls.keyfile
        env:
        - name: ARANGOD_JWT_SECRET
          valueFrom:
            secretKeyRef:
              key: token
              name: example-simple-cluster-jwt
        volumeMounts:
        - mountPath: /secrets/tls
          name: tls-keyfile
      volumes:
      - name: tls-keyfile
        secret:
          defaultMode: 420
          secretName: example-simple-cluster-agent-0mmwt80z-tls-keyfile

---

kind: Service
apiVersion: v1
metadata:
  name: arangodb-exporters-service
  labels:
    app: arangodb-exporter
spec:
  selector:
    app: arangodb-exporter
  ports:
  - name: metrics
    port: 9101

---

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: arangodb-exporter
  namespace: monitoring
  labels:
    team: frontend
    prometheus: kube-prometheus
spec:
  namespaceSelector:
    matchNames:
    - default
  selector:
    matchLabels:
      app: arangodb-exporter
  endpoints:
  - port: metrics
    scheme: https
    tlsConfig:
      insecureSkipVerify: true