This is not the latest version
This documentation is for Linkerd 1.x, an older version with some significant differences. You may want to see the Linkerd 2.x (current) documentation instead.

Telemetry

Linkerd also publishes machine-readable versions of its metrics in multiple formats. These metrics are designed to be polled by external metrics-collection utilities and sent to backends such as Prometheus, InfluxDB, and StatsD.

All of the collected metrics are available as JSON using the /admin/metrics.json endpoint. For instance if you have Linkerd running locally, you can run:

$ curl -s http://localhost:9990/admin/metrics.json?pretty=1 | head -n4
{
  "clnt/zipkin-tracer/available" : 1.0,
  "clnt/zipkin-tracer/cancelled_connects" : 0,
  "clnt/zipkin-tracer/closes" : 294,
  ...

Note that the pretty=1 param is only required for formatting.

To enable additional metrics endpoints, such as Prometheus, InfluxDB, or StatsD, have a look at the Telemetry section of the Linkerd config.

Prometheus

Linkerd provides a metrics endpoint, /admin/metrics/prometheus, specifically for exporting stats to Prometheus. To enable the Prometheus telemeter, add this to your Linkerd configuration file:

telemetry:
- kind: io.l5d.prometheus

You can configure Prometheus to collect stats automatically from your Linkerd instances by using that endpoint as part of your Prometheus scrape config. For instance:

global:
  scrape_interval: 15s
scrape_configs:
  - job_name: 'linkerd'
    metrics_path: /admin/metrics/prometheus
    static_configs:
    - targets:
      - '1.2.3.4:9990'
      - '2.3.4.5:9990'
      - '3.4.5.6:9990'

That configuration would scrape metrics from three separate Linkerd instances.

InfluxDB

Linkerd provides a metrics endpoint, /admin/metrics/influxdb, specifically for exporting stats in InfluxDB LINE protocol. You can configure Telegraf to automatically collect stats from your Linkerd instances. Have a look at the InfluxDB section of the linkerd-examples repo for a complete example.

StatsD

Linkerd supports pushing metrics to a StatsD backend. Simply add a StatsD config block to your Linkerd configuration file:

telemetry:
- kind: io.l5d.statsd
  experimental: true
  prefix: linkerd
  hostname: 127.0.0.1
  port: 8125
  gaugeIntervalMs: 10000
  sampleRate: 0.01