Agent

In the agent deployment pattern, telemetry signals can come from

• Applications instrumented with an OpenTelemetry SDK using the OpenTelemetry Protocol (OTLP)
• Collectors using the OTLP exporter

The signals are sent to a Collector instance that runs alongside the application or on the same host, such as a sidecar or DaemonSet.

Each client-side SDK or downstream Collector is configured with the address of a Collector instance:

1. In the application, the SDK is configured to send OTLP data to a Collector.
2. The Collector is configured to send telemetry data to one or more backends.

Example

In this example of the agent deployment pattern, begin by manually instrumenting a Java application to export metrics using the OpenTelemetry Java SDK, including the default OTEL_METRICS_EXPORTER value, otlp. Next, configure the OTLP exporter with the address of your Collector. For example:

export OTEL_EXPORTER_OTLP_ENDPOINT=http://collector.example.com:4318

Next, configure the Collector running at collector.example.com:4318 as follows:

• Traces
• Metrics
• Logs

receivers:
  otlp: # the OTLP receiver the app is sending traces to
    protocols:
      http:
        endpoint: 0.0.0.0:4318

exporters:
  otlp/jaeger: # Jaeger supports OTLP directly
    endpoint: https://jaeger.example.com:4317
    sending_queue:
      batch:

service:
  pipelines:
    traces/dev:
      receivers: [otlp]
      exporters: [otlp/jaeger]

receivers:
  otlp: # the OTLP receiver the app is sending metrics to
    protocols:
      http:
        endpoint: 0.0.0.0:4318

exporters:
  prometheusremotewrite: # the PRW exporter, to ingest metrics to backend
    endpoint: https://prw.example.com/v1/api/remote_write
    sending_queue:
      batch:

service:
  pipelines:
    metrics/prod:
      receivers: [otlp]
      exporters: [prometheusremotewrite]

receivers:
  otlp: # the OTLP receiver the app is sending logs to
    protocols:
      http:
        endpoint: 0.0.0.0:4318

exporters:
  file: # the File Exporter, to ingest logs to local file
    path: ./app42_example.log
    rotation:

service:
  pipelines:
    logs/dev:
      receivers: [otlp]
      exporters: [file]

To explore this pattern end to end, see the Java or Python examples.

Trade-offs

Here are the key pros and cons of using an agent collector:

Pros:

• Straightforward to get started
• Clear one-to-one mapping between application and Collector

Cons:

• Limited scalability for teams and infrastructure resources
• Inflexible for complex or evolving deployments