Monitor With OpenTelemetry
FusionAuth is a Java application. You can use the OpenTelemetry project to instrument it. Doing so can assist troubleshooting performance issues and make it easier to run.
As of FusionAuth version 1.37.0, FusionAuth has switched to a lighter weight HTTP server backend. The java-http server does not have out of the box instrumentation from the opentelemetry-javaagent.jar. In versions 1.37.0 or later, you can not get request traces from FusionAuth.
See this open GitHub issue for more discussion and to upvote or comment.
FusionAuth has no custom tracing spans embedded, but it can be set up as an OpenTelemetry exporter. Doing so provides useful data about types of requests, database queries, and more.
Set Up the Exporter
Download the Java OpenTelemetry agent. Make it available to the FusionAuth instance. If you are using a zip/deb/rpm, put it in a directory. If using docker, mount the host directory to the container.
Set an environment variable OT_PATH to point to the directory.
Next, you need to configure FusionAuth to use the agent by passing the correct Java command line switches. There are a couple of ways to do this.
You can use Java system properties, environment variables, or edit the fusionauth.properties configuration file. See the configuration reference for more info. For this example, environment variables will be used.
Set this environment variable and make sure it is available when you start FusionAuth (in a startup script, .bashrc, etc.):
Enabling OpenTelemetry export
export FUSIONAUTH_APP_ADDITIONAL_JAVA_ARGS="-javaagent:$OT_PATH/opentelemetry-javaagent.jar"
Next, configure OpenTelemetry to point to your collector. Here’s an example of the environment variables to set to use HoneyComb as your collector. The specific variables needed will vary based on your chosen solution; please consult the collector’s documentation.
Configuring OpenTelemetry collector
# from https://docs.honeycomb.io/getting-data-in/opentelemetry/java-distro/#using-opentelemetry-without-the-honeycomb-distribution
export OTEL_EXPORTER_OTLP_ENDPOINT=https://api.honeycomb.io
export OTEL_EXPORTER_OTLP_HEADERS=x-honeycomb-team=$HONEYCOMB_API_KEY
export OTEL_TRACES_EXPORTER=otlp
export OTEL_SERVICE_NAME=fusionauth-test
export OTEL_TRACES_SAMPLER=traceidratio
export OTEL_TRACES_SAMPLER_ARG=0.5
export OTEL_RESOURCE_ATTRIBUTES=SampleRate=2
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_CLIENT_REQUEST=X-FusionAuth-TenantId
Start FusionAuth and enjoy your new insights.