Agent

The agent collector deployment pattern consists of applications — instrumented with an OpenTelemetry SDK using OpenTelemetry protocol (OTLP) — or other collectors (using the OTLP exporter) that send telemetry signals to a collector instance running with the application or on the same host as the application (such as a sidecar or a daemonset).

Each client-side SDK or downstream collector is configured with a collector location:

1. In the app, 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

A concrete example of the agent collector deployment pattern could look as follows: you manually instrument, say, a Java application to export metrics using the OpenTelemetry Java SDK. In the context of the app, you would set the OTEL_METRICS_EXPORTER to otlp (which is the default value) and configure the OTLP exporter with the address of your collector, for example (in Bash or zsh shell):

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

The collector serving at collector.example.com:4318 would then be configured like so:

• Traces
• Metrics
• Logs

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

processors:
  batch:

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

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

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

processors:
  batch:

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

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

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

processors:
  batch:

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

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

If you want to try it out for yourself, you can have a look at the end-to-end Java or Python examples.

Tradeoffs

Pros:

• Simple to get started
• Clear 1:1 mapping between application and collector

Cons:

• Scalability (human and load-wise)
• Inflexible