Spring Boot provides built-in support for monitoring your application's health and performance, but relying only on internal tools can limit your visibility. External monitoring tools help you track critical metrics, detect issues early, and gain insights across multiple systems. By integrating your Spring Boot application with external monitoring solutions, you ensure better reliability, faster troubleshooting, and more effective performance optimization. In this chapter, you will learn how to connect your application to popular external monitoring tools and understand the benefits they bring to your production environment.

Connecting Spring Boot to Prometheus and Grafana

Spring Boot makes it easy to connect your application to powerful external monitoring tools. Prometheus is a popular monitoring system that collects and stores metrics, while Grafana provides dashboards for visualizing those metrics. Together, they help you track your application's health and performance.

Why Use Prometheus and Grafana?

• Collect detailed metrics about your application's behavior;
• Visualize trends and patterns over time;
• Get alerts when something goes wrong.

Enabling Metrics in Spring Boot

Spring Boot uses Micrometer to expose metrics in a format that Prometheus understands. To get started, add the following dependency to your pom.xml:

<dependency>
  <groupId>io.micrometer</groupId>
  <artifactId>micrometer-registry-prometheus</artifactId>
</dependency>

If you use Gradle, add this to your build.gradle:

dependencies {
  implementation 'io.micrometer:micrometer-registry-prometheus'
}

Exposing Metrics Endpoint

Spring Boot automatically exposes a /actuator/prometheus endpoint for Prometheus to scrape. Make sure the endpoint is enabled in your application.properties:

management.endpoints.web.exposure.include=prometheus

Start your application and visit http://localhost:8080/actuator/prometheus. You should see a text page with metrics data.

Configuring Prometheus to Scrape Metrics

In your Prometheus configuration file (prometheus.yml), add your application's metrics endpoint as a scrape target:

scrape_configs:
  - job_name: 'spring-boot-app'
    static_configs:
      - targets: ['localhost:8080']

Restart Prometheus. It will now collect metrics from your Spring Boot application.

Visualizing Metrics in Grafana

• Add Prometheus as a data source in Grafana;
• Create a new dashboard and select metrics from your Spring Boot application;
• Use charts and graphs to monitor key metrics, such as http_server_requests_seconds_count.

You can now monitor your Spring Boot application in real time using Prometheus and Grafana. This setup helps you quickly spot issues and keep your application running smoothly.

Visualizing Prometheus Metrics in Grafana

Prometheus collects and stores your application's metrics, but you need a tool like Grafana to visualize and analyze this data. Grafana is a popular dashboard platform that connects to Prometheus and displays your metrics using charts and graphs. Follow these steps to get started:

1. Install Grafana;
2. Start Grafana and open the web interface (usually at http://localhost:3000);
3. Log in using the default username and password (admin/admin);
4. Add Prometheus as a data source:
   • Click "Add data source" from the main menu;
   • Select "Prometheus" from the list;
   • Enter your Prometheus server URL (for example, http://localhost:9090);
   • Click "Save & Test" to confirm the connection;
5. Create a new dashboard:
   • Click the "+" icon and select "Dashboard";
   • Add a new panel;
   • In the panel editor, enter a Prometheus query (such as http_server_requests_seconds_count or any metric your Spring application exports);
   • Choose the visualization type (graph, gauge, table, etc.);
   • Click "Apply" to add the panel to your dashboard;
6. Repeat to add more panels for other metrics;
7. Save your dashboard for future use.

You can now monitor your Spring application's metrics in real time with Grafana's interactive dashboards. This setup helps you quickly spot trends, track performance, and catch issues early.