---
title: "Monitor controller | Grafana Agent documentation"
description: "Learn how to monitor controller metrics"
---

# How to monitor controller

The Grafana Agent Flow [component controller](/docs/agent/v0.43/flow/concepts/component_controller/) exposes Prometheus metrics which you can use to investigate the controller state.

Metrics for the controller are exposed at the `/metrics` HTTP endpoint of the Grafana Agent Flow HTTP server, which defaults to listening on `http://localhost:12345`.

> The documentation for the \[`grafana-agent run`]\[grafana-agent run] command describes how to modify the address Grafana Agent Flow listens on for HTTP traffic.

The controller exposes the following metrics:

- `agent_component_controller_evaluating` (Gauge): Set to `1` whenever the component controller is currently evaluating components. This value may be misrepresented depending on how fast evaluations complete or how often evaluations occur.
- `agent_component_controller_running_components` (Gauge): The current number of running components by health. The health is represented in the `health_type` label.
- `agent_component_evaluation_seconds` (Histogram): The time it takes to evaluate components after one of their dependencies is updated.
- `agent_component_dependencies_wait_seconds` (Histogram): Time spent by components waiting to be evaluated after one of their dependencies is updated.
- `agent_component_evaluation_queue_size` (Gauge): The current number of component evaluations waiting to be performed.