zrok/docs/guides/metrics-and-limits/configuring-metrics.md

# Configuring Metrics

A fully configured, production-scale `zrok` service instance looks like this:

![zrok Metrics Architecture](images/metrics-architecture.png)

`zrok` metrics builds on top of the `fabric.usage` event type from OpenZiti. The OpenZiti controller has a number of way to emit events. The `zrok` controller has several ways to consume `fabric.usage` events. Smaller installations could be configured in these ways:

![zrok simplified metrics architecture](images/metrics-architecture-simple.png)

Environments that horizontally scale the `zrok` control plane with multiple controllers should use an AMQP-based queue to "fan out" the metrics workload across the entire control plane. Simpler installations that use a single `zrok` controller can collect `fabric.usage` events from the OpenZiti controller by "tailing" the events log file, or collecting them from the OpenZiti controller's websocket implementation.

## Configuring the OpenZiti Controller

Emitting `fabric.usage` events to a file is currently the most reliable mechanism to capture usage events into `zrok`. We're going to configure the OpenZiti controller to append `fabric.usage` events to a file, by adding this stanza to the OpenZiti controller configuration:

```yaml
events:
  jsonLogger:
    subscriptions:
      - type: fabric.usage
        version: 3
    handler:
      type: file
      format: json
      path: /tmp/fabric-usage.json
```

You'll want to adjust the `events/jsonLogger/handler/path` to wherever you would like to send these events for ingestion into `zrok`. There are additional OpenZiti options that control file rotation. Be sure to consult the OpenZiti docs to tune these settings to be appropriate for your environment.

By default the OpenZiti events infrastructure reports and batches events in 1 minute buckets. 1 minute is too large of an interval to provide a snappy `zrok` metrics experience. So, let's increase the frequency to every 5 seconds. Add this to the `network` stanza of your OpenZiti controller:

```yaml
network:
  intervalAgeThreshold: 5s 
  metricsReportInterval: 5s
```

And you'll want to add this stanza to the router configuration for every router on your OpenZiti network:

```yaml
metrics:
  reportInterval: 5s
  intervalAgeThreshold: 5s
```

Be sure to restart all of the components of your OpenZiti network after making these configuration changes.

## Configuring the zrok Metrics Bridge