Monitoring is essential for maintaining healthy, reliable Spring Boot applications. Without effective monitoring, you risk missing critical issues, performance bottlenecks, or security threats until they become major problems.

Spring Boot Actuator provides powerful, built-in tools for tracking application health, metrics, and runtime behavior. By using Actuator, you gain real-time insights into your application's status, making it easier to detect issues, optimize performance, and ensure smooth operation. In this chapter, you will learn how to leverage Spring Boot Actuator to monitor your applications efficiently and proactively.

What is Spring Boot Actuator?

Spring Boot Actuator is a built-in module that helps you monitor and manage your Spring Boot application. It provides useful endpoints that let you check the application's health, view metrics, and gather operational information without writing extra code.

Purpose of Spring Boot Actuator

• Expose runtime information about your application;
• Allow you to monitor application health and performance;
• Enable easy integration with monitoring tools and dashboards.

Key Endpoints

When you add Spring Boot Actuator, several endpoints become available. The most commonly used are:

• /actuator/health: Shows the health status of your application, such as "UP" or "DOWN";
• /actuator/metrics: Displays metrics like memory usage, CPU load, and request counts.

You can access these endpoints using a web browser or tools like curl.

Adding Actuator to Your Project

Add the following dependency to your pom.xml if you use Maven:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

Or to your build.gradle if you use Gradle:

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
}

Enabling Endpoints

By default, only a few endpoints are enabled. To expose more, add this to your application.properties:

management.endpoints.web.exposure.include=health,metrics

This setting makes /actuator/health and /actuator/metrics available over HTTP.

Example Usage

Start your Spring Boot application. Then open a browser and go to:

• http://localhost:8080/actuator/health — You will see a response like { "status": "UP" }.
• http://localhost:8080/actuator/metrics — You will see a list of available metrics.

Spring Boot Actuator makes it easy to monitor your application’s health and performance. You can enable endpoints, access real-time information, and integrate with monitoring tools—all with minimal setup.