Open Telemetry

Chronicle exports telemetry signals through the OpenTelemetry Protocol (OTLP). Telemetry is always enabled and configured via standard OpenTelemetry environment variables.

Signals

Chronicle exports the following signals:

Signal	Description
Metrics	Application and infrastructure metrics (event sequences, observers, .NET runtime)
Traces	Distributed traces for Chronicle operations (gRPC, HTTP, Orleans)
Logs	Structured application logs

Configuration

Telemetry is configured using standard OpenTelemetry environment variables:

Variable	Default	Description
`OTEL_EXPORTER_OTLP_ENDPOINT`	none	OTLP receiver endpoint (e.g. `http://localhost:4317`)
`OTEL_EXPORTER_OTLP_PROTOCOL`	`grpc`	Export protocol: `grpc` or `http/protobuf`
`OTEL_EXPORTER_OTLP_HEADERS`	none	Additional headers (e.g. API keys for cloud backends)
`OTEL_SERVICE_NAME`	`Chronicle`	Service name reported to the telemetry backend

When OTEL_EXPORTER_OTLP_ENDPOINT is not set, Chronicle does not export telemetry but the instrumentation is still active.

Local development with .NET Aspire Dashboard

The Kernel ships with a docker-compose.yml that starts the .NET Aspire Dashboard as a lightweight all-in-one OTLP receiver and telemetry viewer.

aspire-dashboard:
  image: mcr.microsoft.com/dotnet/aspire-dashboard:latest
  environment:
    - DOTNET_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS=true
    - ALLOW_UNSECURED_TRANSPORT=true
  ports:
    - 18888:18888   # dashboard UI
    - 4317:18889    # OTLP/gRPC receiver

Start the services:

docker compose up -d

Then set the endpoint environment variable before starting the Kernel:

OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 dotnet run

Open the Aspire Dashboard at http://localhost:18888 to view metrics, traces, and logs.

Example: Prometheus and Grafana

For production-grade metric collection, connect Chronicle to a Prometheus-compatible OTLP receiver (for example the OpenTelemetry Collector):

OTEL_EXPORTER_OTLP_ENDPOINT=http://otel-collector:4317

Example: cloud observability backends

Most cloud observability backends (Datadog, Honeycomb, Grafana Cloud, Azure Monitor) accept OTLP. Set the endpoint and any required authentication headers:

OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp.example.com
OTEL_EXPORTER_OTLP_HEADERS=x-api-key=your-api-key

Metrics instrumented

Chronicle instruments the following meters:

Meter	Description
`Cratis.Chronicle`	Chronicle application metrics (events appended, observers, etc.)
`Microsoft.Orleans`	Orleans distributed actor framework metrics
`Grpc.AspNetCore.Server`	gRPC server request metrics
.NET runtime	GC, thread pool, and memory metrics from the .NET runtime

Traces instrumented

Chronicle traces the following activity sources:

Source	Description
`Cratis.Chronicle`	Chronicle internal operations
`Microsoft.Orleans.Runtime`	Orleans runtime activities
`Microsoft.Orleans.Application`	Orleans application activities
HTTP client	Outgoing HTTP requests
ASP.NET Core	Incoming HTTP and gRPC requests
gRPC client	Outgoing gRPC calls

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