Actuator endpoints overview in Spring Boot

Introduction

Actuator endpoints help you see how your Spring Boot app is doing. They give easy info about health, metrics, and more.

You want to check if your app is running well without digging into code.

You need to monitor app performance and resource usage.

You want to see detailed info about app configuration and environment.

You want to track app health in production automatically.

You want to expose info for external monitoring tools.

Syntax

Spring Boot

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

# Example to enable all endpoints
management.endpoints.web.exposure.include=*

You configure which endpoints are available via application.properties or application.yml.

Common endpoints include /actuator/health, /actuator/info, /actuator/metrics.

Examples

This enables only the health and info endpoints to be accessible over HTTP.

Spring Boot

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

This exposes all available actuator endpoints.

Spring Boot

management.endpoints.web.exposure.include=*

Use this command to check the health endpoint output from your running app.

Spring Boot

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

Sample Program

This is a simple Spring Boot app with actuator endpoints enabled for health and info. When you visit the health endpoint, it shows if the app is up.

Spring Boot

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

# application.properties
management.endpoints.web.exposure.include=health,info

# After running, access http://localhost:8080/actuator/health

# Expected JSON response:
# {
#   "status": "UP"
# }

Important Notes

By default, only the health and info endpoints are enabled and exposed.

Some endpoints may require authentication in production for security.

You can customize actuator endpoints to add your own checks or info.

Summary

Actuator endpoints give you quick info about your Spring Boot app's health and status.

You enable and expose them via configuration properties.

Common endpoints include health, info, and metrics.

Practice

1. What is the main purpose of Spring Boot Actuator endpoints?

easy

A. To handle user authentication and authorization

B. To serve static web content like images and CSS

C. To manage database connections automatically

D. To provide information about the application's health and status

Solution

1. Step 1: Understand Actuator endpoints role

   Actuator endpoints are designed to give quick info about the app's health and status.

2. Step 2: Compare with other options

   Authentication, database management, and static content serving are not the main roles of Actuator.

3. Final Answer:

   To provide information about the application's health and status -> Option D

4. Quick Check:

   Actuator endpoints = app health info [OK]

Hint: Remember: Actuator = app health and metrics info [OK]

Common Mistakes:

• Confusing Actuator with security features
• Thinking Actuator manages database connections
• Assuming Actuator serves static files

2. Which property enables the exposure of all Actuator endpoints in Spring Boot?

easy

A. management.endpoints.web.exposure.include=*

B. spring.boot.actuator.enabled=true

C. management.endpoint.health.enabled=true

D. server.port=8080

Solution

1. Step 1: Identify property to expose endpoints

   The property management.endpoints.web.exposure.include=* exposes all Actuator endpoints.

2. Step 2: Check other options

   spring.boot.actuator.enabled is not a valid property; health endpoint enabling is specific, and server.port sets the server port.

3. Final Answer:

   management.endpoints.web.exposure.include=* -> Option A

4. Quick Check:

   Expose all endpoints = management.endpoints.web.exposure.include=* [OK]

Hint: Use '*' in exposure.include to enable all endpoints [OK]

Common Mistakes:

• Using incorrect property names
• Confusing enabling endpoints with enabling server
• Trying to enable endpoints individually without exposure property

3. Given the following configuration:

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

Which endpoints will be accessible via HTTP?

medium

A. Only /health and /info endpoints

B. All Actuator endpoints

C. No endpoints are accessible

D. Only /metrics endpoint

Solution

1. Step 1: Read the exposure.include property

   The property lists health and info, so only these endpoints are exposed.

2. Step 2: Understand what exposure.include controls

   It controls which endpoints are accessible via HTTP; others remain hidden.

3. Final Answer:

   Only /health and /info endpoints -> Option A

4. Quick Check:

   Exposure include = health,info means only those endpoints [OK]

Hint: Check exposure.include list to know accessible endpoints [OK]

Common Mistakes:

• Assuming all endpoints are exposed by default
• Confusing exposure.include with enabling endpoints
• Thinking metrics endpoint is included without listing it

4. You configured management.endpoints.web.exposure.include=health,metrics but the /metrics endpoint returns 404. What is the likely cause?

medium

A. The metrics endpoint is disabled by default and needs explicit enabling

B. The health endpoint is conflicting with metrics

C. The application is missing the actuator dependency

D. The server port is incorrect

Solution

1. Step 1: Check if actuator dependency is present

   Without the actuator library, endpoints like /metrics won't exist, causing 404.

2. Step 2: Verify other options

   Metrics endpoint is enabled by exposure.include; health does not conflict; server port affects access but not endpoint existence.

3. Final Answer:

   The application is missing the actuator dependency -> Option C

4. Quick Check:

   Missing actuator dependency = 404 on endpoints [OK]

Hint: Always add actuator dependency to use Actuator endpoints [OK]

Common Mistakes:

• Assuming endpoints work without actuator dependency
• Blaming port or conflicts instead of missing library
• Thinking exposure.include enables endpoints without actuator

5. You want to monitor your Spring Boot app's health, info, and metrics endpoints but only expose health and info publicly. How do you configure this securely?

hard

A. Set management.endpoints.web.exposure.include=health,info,metrics and disable security

B. Set management.endpoints.web.exposure.include=health,info and secure /metrics with authentication

C. Expose all endpoints with * and rely on firewall rules

D. Disable all endpoints except metrics

Solution

1. Step 1: Expose only health and info endpoints publicly

   Use management.endpoints.web.exposure.include=health,info to expose only those endpoints.

2. Step 2: Secure metrics endpoint separately

   Keep metrics endpoint enabled internally and protect it with authentication or network rules.

3. Final Answer:

   Set management.endpoints.web.exposure.include=health,info and secure /metrics with authentication -> Option B

4. Quick Check:

   Expose only needed endpoints publicly, secure others [OK]

Hint: Expose only needed endpoints publicly; secure sensitive ones [OK]

Common Mistakes:

• Exposing all endpoints without security
• Disabling security to simplify access
• Exposing metrics publicly without protection