Spring Boot Actuator

What Is Actuator?

Spring Boot Actuator provides production-ready features for monitoring and managing your application. Actuator exposes endpoints to view health, metrics, info, and more.

Adding the Dependency

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

Once added, restart the application. Many new endpoints become available at /actuator.

Active Endpoints

By default, only two endpoints are active:

Access via browser or curl:

curl http://localhost:8080/actuator/health

{
  "status": "UP"
}

Enabling All Endpoints

# application.properties
management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always

Now all endpoints are active. Check the full list:

curl http://localhost:8080/actuator

{
  "_links": {
    "self": { "href": "/actuator", "templated": false },
    "health": { "href": "/actuator/health" },
    "info": { "href": "/actuator/info" },
    "beans": { "href": "/actuator/beans" },
    "metrics": { "href": "/actuator/metrics" },
    "env": { "href": "/actuator/env" },
    "mappings": { "href": "/actuator/mappings" }
  }
}

Important Endpoints

Health Check

management.endpoint.health.show-details=always
management.health.db.enabled=true
management.health.diskspace.enabled=true

curl http://localhost:8080/actuator/health

{
  "status": "UP",
  "components": {
    "db": { "status": "UP", "details": { "database": "H2" } },
    "diskSpace": { "status": "UP" }
  }
}

Info Endpoint

Add info in application.properties:

info.app.name=My Spring Boot App
info.app.version=1.0.0
info.app.description=Spring Boot tutorial application
info.app.author=Luthfi

curl http://localhost:8080/actuator/info

{
  "app": {
    "name": "My Spring Boot App",
    "version": "1.0.0",
    "description": "Spring Boot tutorial application",
    "author": "Luthfi"
  }
}

Metrics Endpoint

# All metrics
curl http://localhost:8080/actuator/metrics

# A specific metric
curl http://localhost:8080/actuator/metrics/jvm.memory.used

# HTTP request metrics
curl http://localhost:8080/actuator/metrics/http.server.requests

Environment Endpoint

curl http://localhost:8080/actuator/env

Shows all environment properties, including system properties and application properties.

Exposure Configuration

Exposing Specific Endpoints

# Only expose certain endpoints
management.endpoints.web.exposure.include=health,info,metrics

Exposing via JMX

management.endpoints.jmx.exposure.include=health,info

Custom Base Path

# Replace /actuator with /manage
management.endpoints.web.base-path=/manage

Disabling an Endpoint

# Disable the env endpoint
management.endpoint.env.enabled=false

Custom Health Indicator

Create a custom health check for a specific component:

@Component
public class ExternalApiHealthIndicator implements HealthIndicator {

    private final ExternalApiService apiService;

    public ExternalApiHealthIndicator(ExternalApiService apiService) {
        this.apiService = apiService;
    }

    @Override
    public Health health() {
        try {
            boolean isUp = apiService.checkConnection();
            if (isUp) {
                return Health.up()
                    .withDetail("external-api", "Connected")
                    .build();
            } else {
                return Health.down()
                    .withDetail("external-api", "Not responding")
                    .build();
            }
        } catch (Exception e) {
            return Health.down()
                .withDetail("external-api", e.getMessage())
                .build();
        }
    }
}

@Component
public class DiskSpaceHealthIndicator implements HealthIndicator {

    @Override
    public Health health() {
        File root = new File("/");
        long freeGB = root.getFreeSpace() / (1024 * 1024 * 1024);

        if (freeGB < 1) {
            return Health.down()
                .withDetail("free-space", freeGB + " GB")
                .build();
        }
        return Health.up()
            .withDetail("free-space", freeGB + " GB")
            .build();
    }
}

Production Configuration

# Production config
management.endpoints.web.exposure.include=health,info,metrics
management.endpoint.health.show-details=when-authorized
management.health.db.enabled=true
management.health.livenessstate.enabled=true
management.health.readinessstate.enabled=true

# Info from git
info.git.mode=full
info.git.branch=main

Monitoring with Micrometer

Actuator uses Micrometer for metrics. Integrating with monitoring systems:

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

# Prometheus endpoint
management.endpoints.web.exposure.include=health,info,prometheus
management.metrics.tags.application=myapp

# Prometheus metrics
curl http://localhost:8080/actuator/prometheus

Actuator helps you monitor the application in production. In the next chapter, we'll learn about Spring Security to protect the application.