How do you configure Prometheus metrics in a Spring Boot application?

Table of Contents

• Introduction
• Steps to Configure Prometheus Metrics in a Spring Boot Application
  • 1. Add Dependencies for Prometheus and Spring Boot Actuator
    • Add Dependencies in pom.xml (Maven)
    • Add Dependencies in build.gradle (Gradle)
  • 2. Enable Prometheus Metrics in Spring Boot
    • Configure application.properties
    • Configure application.yml
  • 3. Expose Prometheus Metrics via /actuator/prometheus
  • 4. Configure Prometheus to Scrape Metrics
    • Configure prometheus.yml
  • 5. Visualize Metrics with Grafana (Optional)
    • Set Up Grafana:
    • Create Grafana Dashboards:
  • 6. Monitor and Analyze Metrics
• Conclusion

Introduction

Prometheus is a popular open-source monitoring and alerting system designed for reliability and scalability. When integrated with Spring Boot, it can provide detailed insights into the health and performance of your application. By configuring Prometheus metrics in a Spring Boot application, you can expose important metrics like system health, resource usage, request handling, and more. In this guide, we will walk you through the steps to configure Prometheus metrics in a Spring Boot application using the Spring Boot Actuator and Prometheus integration.

Steps to Configure Prometheus Metrics in a Spring Boot Application

1. Add Dependencies for Prometheus and Spring Boot Actuator

To begin integrating Prometheus with Spring Boot, you need to add the necessary dependencies in your project.

Add Dependencies in pom.xml (Maven)

Add Dependencies in build.gradle (Gradle)

These dependencies include Spring Boot Actuator (which exposes various built-in metrics) and Micrometer (which integrates with Prometheus to expose the metrics in a format that Prometheus can scrape).

2. Enable Prometheus Metrics in Spring Boot

Next, you need to enable the Prometheus metrics export and configure Spring Boot to expose the metrics in the correct format.

Configure application.properties

Configure application.yml

This configuration tells Spring Boot to expose the prometheus endpoint and enables the export of metrics in the Prometheus format.

3. Expose Prometheus Metrics via /actuator/prometheus

Once the above dependencies and configuration are in place, Spring Boot will expose metrics on the /actuator/prometheus endpoint. Prometheus will scrape this endpoint to collect metrics from your application.

For example, when your Spring Boot application is running on localhost:8080, you can access Prometheus-formatted metrics at:

This endpoint will expose various default metrics, including:

• HTTP request metrics (e.g., request counts, response times)
• JVM metrics (e.g., memory usage, garbage collection stats)
• System metrics (e.g., CPU usage, disk usage)

4. Configure Prometheus to Scrape Metrics

Now that your Spring Boot application exposes the Prometheus metrics, you need to configure Prometheus to scrape them.

Configure prometheus.yml

Modify the Prometheus configuration file (prometheus.yml) to scrape the metrics from your Spring Boot application. Add the following configuration to the scrape_configs section:

In this configuration:

• job_name: The name of the job (e.g., spring-boot-app).
• metrics_path: The endpoint where Prometheus will fetch metrics (/actuator/prometheus).
• targets: The target URL where Prometheus will scrape the metrics from (e.g., localhost:8080).

5. Visualize Metrics with Grafana (Optional)

To visualize the metrics collected by Prometheus, you can use Grafana, a popular open-source dashboarding tool.

Set Up Grafana:

1. Install Grafana from the official website.
2. Launch Grafana and open it in your browser (usually at http://localhost:3000).
3. Add Prometheus as a data source:
   • Navigate to Configuration -> Data Sources.
   • Select Prometheus as the data source.
   • Set the URL to http://localhost:9090 (or wherever Prometheus is running).
4. Save and test the connection.

Create Grafana Dashboards:

1. In Grafana, you can create custom dashboards to visualize the metrics Prometheus collects, such as HTTP request counts, response times, CPU usage, and more.
2. Alternatively, you can use pre-built Grafana dashboards for Prometheus metrics.

6. Monitor and Analyze Metrics

Once everything is set up, you can monitor your Spring Boot application’s performance, resource usage, and overall health using the Prometheus and Grafana integration. Prometheus will periodically scrape the metrics, and Grafana will display them in real-time, helping you identify any issues or trends.

Conclusion

Configuring Prometheus metrics in a Spring Boot application is a straightforward process that involves adding the necessary dependencies, enabling the Prometheus endpoint, and configuring Prometheus to scrape the metrics. By using Spring Boot Actuator and Micrometer, you can easily expose various system and application metrics, which Prometheus can collect and store. For more advanced use cases, you can integrate Grafana for visualizing the data. This setup provides a powerful monitoring solution to track your application's performance, identify bottlenecks, and ensure its reliability.