Exporter Filterproxy

A proxy that can proxy and filter other Prometheus exporters. It is intended to expose a subset of metrics of an exporter, for example to expose kube-state-metrics that only relate to a specific namespace.

Quick Start

You can run the exporter-filterproxy using docker-compose or in kubernetes using kind.

Docker Compose

To test the exporter-filterproxy in docker and exposing static targets you can run:

make docker-compose-up

You can now access sample metrics at http://localhost:8082/node and filter these metrics using parameters. To only access metrics related to CPU 2, access http://localhost:8082/node?cpu=2.

Further there is a Prometheus at http://localhost:9090/ that only accesses node metrics that are related to CPU 2.

KinD

To test the exporter-filterproxy in Kubernetes using the Kubernetes service discovery you can run:

make kind

This will start a local kind cluster and deploy a exporter-filterproxy that proxies the metrics of the CoreDNS service, as well as a Prometheus instance.

Once the cluster started you can expose the test Prometheus using port-forward

kubectl port-forward svc/prometheus 9090

You should see two discovered targets through the exporter-filterproxy when you open http://localhost:9090/targets

Configuration

The filterproxy is configured through a YAML file, where you can configure one or more upstream endpoints of Prometheus exporters.

Field	Description
addr	On what address the filterproxy will listen on
endpoints	A map of upstream Prometheus exporters that will be proxied
endpoints.<exporter>.path	On what path the exporter <exporter> will be proxied
endpoints.<exporter>.target	The address where to query the exporter <exporter> exposes metrics
endpoints.<exporter>.kubernetes_target	Configuration to expose a Kubernetes service
endpoints.<exporter>.kubernetes_target.name	The name of the Kubernetes service
endpoints.<exporter>.kubernetes_target.namespace	The namespace of the Kubernetes service
endpoints.<exporter>.kubernetes_target.port	The port on which metrics are exposed on
endpoints.<exporter>.kubernetes_target.path	The path the exporter exposes the metrics on
endpoints.<exporter>.kubernetes_target.scheme	What scheme the exporter uses to expose metrics (http or https)
endpoints.<exporter>.refresh_interval	If set the proxy will only refresh the metrics every refresh interval instead of forwarding every request
endpoints.<exporter>.insecure_skip_verify	Whether the proxy should skip verifying the exporters certificate
endpoints.<exporter>.auth	How to authenticate to the exporter. This either has type: Bearer and the bearer token needs to be specified in the token field, or it can have type: Kubernetes, in which case the proxy will authenticate using the service account of the pod it is running in (will only work when running in Kubernetes)

The following example configuration will run the filterproxy on port 8082. It will expose a kube-state-metrics exporter running at kube.example.com on at the path kube-state-metrics and will authenticate to it by putting the bearer token foobar in the authorization header. The TLS certificate will not be verified and the metrics will be refreshed every 5 seconds.

It will also expose node-exporter metrics running at node.example.com at the path /node.

addr: :8082
endpoints:
  kube_state_metrics:
    path: /kube-state-metrics
    target: https://kube.example.com:8077/metrics
    refresh_interval: 5s
    insecure_skip_verify: true
    auth:
      type: Bearer
      token: foobar
  node:
    path: /node
    target: http://node.example.com:9100/metrics
    refresh_interval: 7s

Development

Run tests

To run tests simply run

make test