How do you implement health checks with Spring Boot Admin?

Table of Contents

• Introduction
  • Steps to Implement Health Checks with Spring Boot Admin
    • 1. Add Required Dependencies
    • 2. Enable Spring Boot Admin Server
    • 3. Enable Actuator in the Client Application
    • 4. Configure the Client Application to Register with the Admin Server
    • 5. Access Health Data in Spring Boot Admin
  • How Spring Boot Admin Displays Health Information
  • Custom Health Indicators
  • Security Considerations
• Conclusion

Introduction

In production environments, it's essential to monitor the health of your applications to ensure they are running smoothly and meet performance expectations. Spring Boot Admin integrates with Spring Boot Actuator to provide a simple way to monitor the health of applications. Spring Boot Actuator exposes several built-in health indicators that report the status of your application (e.g., whether it's up, down, or experiencing issues), and Spring Boot Admin aggregates this information into a centralized UI.

In this guide, we'll walk you through how to implement and configure health checks using Spring Boot Admin, how Spring Boot Admin integrates with Actuator to display health information, and how you can customize health checks for more detailed monitoring.

Steps to Implement Health Checks with Spring Boot Admin

To implement health checks with Spring Boot Admin, you need to use Spring Boot Actuator to expose the /health endpoint and configure Spring Boot Admin to visualize this health information. Below are the key steps involved in setting up health checks:

1. Add Required Dependencies

First, ensure that you include the required dependencies in both the Spring Boot Admin Server and the client application (which will be monitored).

• Admin Server: Add the Spring Boot Admin Server dependency in your admin server application.

Admin Server **pom.xml**:

• Client Application: The client application needs the Spring Boot Admin starter dependency, which will allow it to expose health data and register itself with the admin server.

Client Application **pom.xml**:

2. Enable Spring Boot Admin Server

In your Spring Boot Admin Server application, add the @EnableAdminServer annotation to enable the Admin Server functionality.

Admin Server Application (**AdminServerApplication.java**):

Once the server application is running, it will serve as the central hub for monitoring and managing client applications.

3. Enable Actuator in the Client Application

In the client application, you need to enable Spring Boot Actuator to expose the /health endpoint, which provides the health status of the application.

Add the spring-boot-starter-actuator dependency to the client application.

Client Application **pom.xml**:

Next, enable the health endpoint in application.properties or application.yml:

Client Application **application.properties**:

This configuration ensures that the /health endpoint is available and exposed by the Spring Boot Actuator. The health check will be automatically performed, and its results will be available at:

4. Configure the Client Application to Register with the Admin Server

You need to configure the client application to register with the Spring Boot Admin Server. This is done by specifying the URL of the Admin Server.

Add the following configuration to the client application’s application.properties:

This configuration makes the client application register itself with the Spring Boot Admin server running at http://localhost:8081.

5. Access Health Data in Spring Boot Admin

Once the client application is configured and running, Spring Boot Admin will automatically pick up the /health endpoint data from the client. The health status will be displayed on the Admin Server’s dashboard under the "Health" tab for each registered application.

1. Start both the Admin Server and client applications.
2. Visit the Admin Server’s web interface (usually accessible at http://localhost:8081).
3. From the dashboard, click on the registered client application to view detailed health information.

How Spring Boot Admin Displays Health Information

Spring Boot Admin integrates seamlessly with Spring Boot Actuator’s health check system. The /health endpoint in the client application returns a JSON response containing various health indicators. The most common statuses are:

• UP: The application is healthy and running without issues.
• DOWN: The application has issues (could be due to unavailable resources, services, etc.).
• OUT_OF_SERVICE: The application is in maintenance mode.
• UNKNOWN: The health status could not be determined.

For example, the /health endpoint might return the following JSON response:

Spring Boot Admin aggregates this health information and displays it in a user-friendly format on the dashboard.

• Health Overview: The "Health" tab on the Spring Boot Admin dashboard provides a simple overview of the application's health status. It will show whether the application is UP, DOWN, or in another state.
• Detailed Health Indicators: If you click into an individual application, you will be able to see the detailed health information, including the status of various components like disk space, database, message brokers, etc.

Custom Health Indicators

You can also create custom health checks for your application. For example, if you want to add a custom check for a third-party service, you can create a HealthIndicator bean.

Example: Custom Health Check for a Third-Party Service:

When this custom health check is added to your application, Spring Boot Admin will display it as part of the health information for the registered application.

Security Considerations

When exposing health data, especially in production, you may want to secure access to the /health endpoint to avoid exposing sensitive information. This can be done using Spring Security.

Here’s an example of securing the /health endpoint:

In **application.properties**:

This configuration ensures that detailed health information is shown only when the user is authorized. You can configure Spring Security to secure access to Actuator endpoints:

This ensures that sensitive health check information is secured and can only be accessed by authorized users.

Conclusion

Implementing health checks in Spring Boot Admin is a great way to monitor the health and performance of your applications in real time. By integrating Spring Boot Actuator and configuring Spring Boot Admin, you can easily track the health status of your applications and get insights into their operational state. Custom health checks further enhance your monitoring by allowing you to track specific application components or external dependencies. With its rich features and easy setup, Spring Boot Admin helps maintain the reliability of your Spring Boot applications in production environments.