exporter-merger

⚠️ We archived this project because we don't use it anymore and in the meantime some other solutions for the problem described in prometheus/prometheus#3756 became available.

Merges Prometheus metrics from multiple sources.

Development Status exporter-merger is in an early development phase. Expect incompatible changes and abandoment at any time.

But Why?!

prometheus/prometheus#3756

Usage

exporter-merger needs a configuration file. Currently, nothing but URLs are accepted:

exporters:
- url: http://localhost:9100/metrics
- url: http://localhost:9101/metrics

To start the exporter:

exporter-merger --config-path merger.yaml --listen-port 8080

Environment variables

Alternatively configuration can be passed via environment variables, here is relevant part of exporter-merger -h output:

      --listen-port int      Listen port for the HTTP server. (ENV:MERGER_PORT) (default 8080)
      --url stringSlice      URL to scrape. Can be speficied multiple times. (ENV:MERGER_URLS,space-seperated)

Kubernetes

The exporter-merger is supposed to run as a sidecar. Here is an example config with nginx-exporter:

apiVersion: apps/v1
kind: Deployment

metadata:
  name: my-nginx
  labels:
    app: my-nginx

spec:
  selector:
    matchLabels:
      app: my-nginx

  template:
    metadata:
      name: my-nginx
      labels:
        app: my-nginx
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "8080"

    spec:
      containers:
      - name: "nginx"
        image: "my-nginx" # nginx image with modified config file

        volumeMounts:
        - name: mtail
          mountPath: /var/log/nginx/mtail

      - name: nginx-exporter
        image: quay.io/rebuy/nginx-exporter:v1.1.0
        ports:
        - containerPort: 9397
        env:
        - name: NGINX_ACCESS_LOGS
          value: /var/log/nginx/mtail/access.log
        - name: NGINX_STATUS_URI
          value: http://localhost:8888/nginx_status
        volumeMounts:
        - name: mtail
          mountPath: /var/log/nginx/mtail

      - name: exporter-merger
        image: quay.io/rebuy/exporter-merger:v0.2.0
        ports:
        - containerPort: 8080
        env:
        # space-separated list of URLs
        - name: MERGER_URLS
          value: http://localhost:9000/prometheus/metrics http://localhost:9397/metrics
        # default exposed port, change only if need other than default 8080
        # - name: MERGER_PORT
        #   value: 8080

Planned Features

• Allow transforming of metrics from backend exporters.
  • eg add a prefix to the metric names
  • eg add labels to the metrics
• Allow dynamic adding of exporters.