How to expose metrics from sdk and HostMetrics to the same port?

[JessicaJHee]

If possible I'm looking combine both metrics from the sdk and HostMetrics to be exposed at 9464/metrics

With this implementation I get: Error: MetricReader can not be bound to a MeterProvider again.

const prometheus = new PrometheusExporter();
const meterProvider = new MeterProvider({
  readers: [prometheus],
});

const sdk = new NodeSDK({
  metricReader: prometheus,
  instrumentations: [
    getNodeAutoInstrumentations(),
    new RuntimeNodeInstrumentation(),
  ],
});

sdk.start();

const hostMetrics = new HostMetrics({ meterProvider: meterProvider });
hostMetrics.start();

Is this possible? Thanks for the help in advance!

[pichlermarc]

Hi, you're adding the exporter to two different MeterProviders, which is not supported.

Specifically NodeSDK instantiates another instance of MeterProviderand tries to add the PrometheusExporter to the new one but it was already bound on the MeterProvider you created in L2-L4.

Doing this instead should work:

const prometheus = new PrometheusExporter();

const sdk = new NodeSDK({
  metricReader: prometheus,
  instrumentations: [
    getNodeAutoInstrumentations(),
    new RuntimeNodeInstrumentation(),
  ],
});

sdk.start();

import {metrics} from '@opentelemetry/api';

// important only get `MeterProvider` after `sdk.start()` otherwise it will be no-op.
const hostMetrics = new HostMetrics({ meterProvider: metrics.getMeterProvider() });
hostMetrics.start();

[JessicaJHee]

This worked perfectly, thank you so much for your help!