Observability with OpenTelemetry

wasmCloud is designed to support cloud native observability standards using OpenTelemetry (OTEL). OpenTelemetry is an open source project defining common APIs and standards for telemetry in cloud native systems. As of v1.0, wasmCloud emits traces, logs, and metrics as OTEL signals.

Data flow

A wasmCloud observability ecosystem must include an OTEL collector, a vendor-agnostic application from the OpenTelemetry project that processes and routes signals. The wasmCloud host emits signals to the OTEL collector, which passes the data on to observability systems such as Grafana.

The OTEL documentation provides detailed instructions on how to install and run the OTEL collector. Additionally, you can find a sample configuration for an OTEL collector in the wasmCloud observability ecosystem demo on GitHub.

While the OTEL collector is the recommended point of configuration for complex signal routing, there are a set of core configurations available at the level of a wasmCloud host. The host can be configured using environment variables or host config flags.

Configuration

Enable the wasmCloud host to emit all OTEL signals with the WASMCLOUD_OBSERVABILITY_ENABLED environment variable:

bash

WASMCLOUD_OBSERVABILITY_ENABLED="true"

By default, OTEL signals are exported on port 4318, the standard HTTP/OpenTelemetry Protocol (otlp) port. wasmCloud only supports the otlp format. The endpoint for all otlp exports may be overwritten with the OTEL_EXPORTER_OTLP_ENDPOINT environment variable:

bash

OTEL_EXPORTER_OTLP_ENDPOINT=http://my-custom-host:4318

It is also possible to enable and overwrite endpoints for only specific signals—see the pages for traces, logs, and metrics for more details.

While these options are typically passed as part of host configuration, you can launch a wasmCloud observability ecosystem locally by passing environment variables to wash up:

bash

WASMCLOUD_OBSERVABILITY_ENABLED="true" wash up

Launch a wasmCloud observability ecosystem

A set of sample configurations and Docker Compose files are available on GitHub. These samples can be used to launch an example wasmCloud observability ecosystem. Clone or download the wasmCloud repository:

bash

git clone https://github.com/wasmCloud/wasmCloud.git

Change directory to examples/docker:

bash

cd wasmcloud/examples/docker

Run the docker-compose-otel.yml file to launch...

• Grafana for dashboards
• The OTEL collector for ingesting OTLP signals from the wasmcloud host
• Tempo for processing traces and passing them to Grafana
• Loki for processing logs and passing them to Grafana
• Prometheus for metrics (wasmCloud metrics support still in development)

bash

docker compose -f docker-compose-otel.yml up

Make sure a wasmCloud host is running locally with OTEL signals enabled:

bash

WASMCLOUD_OBSERVABILITY_ENABLED="true" wash up

Now you can access Grafana's "Explore" interface at http://localhost:5050/explore.

Advanced options

Because wasmCloud's implementation of OpenTelemetry observability uses upstream OTEL libraries, a variety of advanced configuration options are available via environment variables defined in the upstream OTEL SDK and OTLP Exporter SDK.

For example, users have several options for trace sampling and log batch management. Not all upstream options are supported—for example, the wasmCloud host does not support changing format to gRPC.

Note

In cases where the system receives conflicting configurations for the same option via environment variable and command line argument, upstream OpenTelemetry libraries prioritize configurations set via environment variable. Refer to the OpenTelemetry documentation for more details.

Further reading

Signal-specific options on the wasmCloud host are detailed on the traces, logs, and metrics pages. For more information on OpenTelemetry, refer to the project documentation.