Reaper exposes all its metrics in a Prometheus-ready format under the /prometheusMetrics endpoint on the admin port.

It’s fairly straightforward to configure Prometheus to grab them. The config can look something like:

  - job_name: 'reaper'
    metrics_path: '/prometheusMetrics'
    scrape_interval: 5s
      - targets: ['host.docker.internal:8081']
  • The host.docker.internal tells a Prometheus instance running inside a docker container to connect to the host’s 8081 port where Raper runs from a JAR.