Function Autoscaler Observability

The function autoscaler emits structured logs, Prometheus metrics that explain dependency health statuses and scaling decisions, and OpenTelemetry spans for outbound calls to its dependencies. The Prometheus exporter serves metrics on the address configured in server.metrics.exporters. The local settings file at crates/server/resources/settings-local.yaml uses 0.0.0.0:41338.

Job and namespace labels follow the standard NVCF naming convention for the cluster that runs the function autoscaler.

Metric reference

Tracing

The function autoscaler emits OpenTelemetry spans for outbound calls to the timeseries database and the NVCF API, with the OTLP endpoint and span filter configurable under server.tracing.

Logging

The function autoscaler writes structured logs to stdout. Set log filter directives in the server.envfilter_directive configuration field. The format follows the tracing_subscriber env filter syntax (Rust ecosystem standard):

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server:
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  envfilter_directive: "server=info,rs_autoscaler=debug,rs_autoscaler::cassandra=warn,info"

The same syntax applies to server.tracing.logging_envfilter_directive if you separate logging and tracing filters.

Useful target prefixes:

See also

• Function Autoscaler Operations for common symptoms tied to these metrics and log lines.
• Architecture for the components that emit each signal.
• Configure Autoscaling for setting per-function scaling bounds and policy via the NVCF API.