Spring Boot Admin: Complete Setup Guide for Service Monitoring & Alerting

Introduction

Spring Boot Admin is used for managing and monitoring Spring Boot applications. It can monitor service health, online status, and JVM metrics. The tool consists of a server ( spring-boot-admin-server) and a client ( spring-boot-admin-client) communicating via HTTP. In monolithic projects, each application must integrate the client to be monitored. In Spring Cloud projects, the server pulls application information directly from the service registry, so individual microservices do not need the client dependency.

Display application monitoring status

Application online/offline monitoring

View JVM and thread information

Visualize and download log files

Dynamically change log levels

Track HTTP request traces

Server Setup

1. Dependencies

<!--Used to check system monitoring-->
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</artifactId>
  </dependency>
  <!--Spring Boot Admin Server monitoring server-->
  <dependency>
      <groupId>de.codecentric</groupId>
      <artifactId>spring-boot-admin-starter-server</artifactId>
      <version>2.3.1</version>
  </dependency>
  <!--Add security protection to prevent unauthorized access-->
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-security</artifactId>
  </dependency>

2. Enable Admin Server

Add @EnableAdminServer on the main application class.

3. Security Configuration

import de.codecentric.boot.admin.server.config.AdminServerProperties;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.web.authentication.SavedRequestAwareAuthenticationSuccessHandler;
import org.springframework.security.web.csrf.CookieCsrfTokenRepository;

@Configuration
public class SecuritySecureConfig extends WebSecurityConfigurerAdapter {

    private final String adminContextPath;

    public SecuritySecureConfig(AdminServerProperties adminServerProperties) {
        this.adminContextPath = adminServerProperties.getContextPath();
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        // Login success handler
        SavedRequestAwareAuthenticationSuccessHandler successHandler = new SavedRequestAwareAuthenticationSuccessHandler();
        successHandler.setTargetUrlParameter("redirectTo");
        successHandler.setDefaultTargetUrl(adminContextPath + "/");

        http.authorizeRequests()
                // Allow static resources
                .antMatchers(adminContextPath + "/assets/**").permitAll()
                // Allow login page
                .antMatchers(adminContextPath + "/login", "/css/**", "/js/**", "/image/*").permitAll()
                // All other requests require authentication
                .anyRequest().authenticated()
                .and()
                // Custom login page
                .formLogin().loginPage(adminContextPath + "/login").successHandler(successHandler).and()
                // Custom logout
                .logout().logoutUrl(adminContextPath + "/logout").and()
                .httpBasic().and()
                .csrf()
                .csrfTokenRepository(CookieCsrfTokenRepository.withHttpOnlyFalse())
                .ignoringAntMatchers(
                        "/instances",
                        "/actuator/**"
                );
    }
}

4. YAML Configuration

server:
  port: 9111
spring:
  boot:
    admin:
      ui:
        title: HMB Service Monitoring Center
      client:
        instance:
          metadata:
            tags:
              environment: local
      # Endpoints to probe on clients
      probed-endpoints: health,env,metrics,httptrace:trace,threaddump:dump,jolokia,info,logfile,refresh,flyway,liquibase,heapdump,loggers,auditevents
      monitor: # Monitoring request timeout
        default-timeout: 20000
  security: # Set username/password
    user:
      name: admin
      password: admin
# Detailed endpoint monitoring info
management:  
  trace:
    http:
      enabled: true
  endpoints:
    web:
      exposure:
        include: "*"
  endpoint:
    health:
      show-details: always

5. Custom Status Change Notifier

Implement a notifier to send alerts when service status changes. The example builds a message with service name, URL, status, details, and timestamp, then returns a Mono<Void> where the actual notification logic (e.g., SMS) would be placed.

import de.codecentric.boot.admin.server.domain.entities.Instance;
import de.codecentric.boot.admin.server.domain.entities.InstanceRepository;
import de.codecentric.boot.admin.server.domain.events.InstanceEvent;
import de.codecentric.boot.admin.server.notify.AbstractStatusChangeNotifier;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;

@Component
public class WarnNotifier extends AbstractStatusChangeNotifier {
    public WarnNotifier(InstanceRepository repository) {
        super(repository);
    }

    @Override
    protected Mono<Void> doNotify(InstanceEvent event, Instance instance) {
        // Service name
        String serviceName = instance.getRegistration().getName();
        // Service URL
        String serviceUrl = instance.getRegistration().getServiceUrl();
        // Service status
        String status = instance.getStatusInfo().getStatus();
        // Details
        Map<String, Object> details = instance.getStatusInfo().getDetails();
        // Current time
        Date date = new Date();
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String format = simpleDateFormat.format(date);
        // Build message
        StringBuilder str = new StringBuilder();
        str.append("Service Name: [" + serviceName + "] 
");
        str.append("Service Status: [" + status + "] 
");
        str.append("Address: [" + serviceUrl + "]
");
        str.append("Time: " + format + "
");

        return Mono.fromRunnable(() -> {
            // Write your notification method here
            // e.g., send SMS when service goes offline
        });
    }
}

Client Setup

1. Dependencies

<dependency>
      <groupId>de.codecentric</groupId>
      <artifactId>spring-boot-admin-starter-client</artifactId>
      <version>2.3.1</version>
  </dependency>
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</artifactId>
  </dependency>

2. YAML Configuration

server:
  port: 9222

spring:
  application:
    name: client
  boot:
    admin:
      client: # Spring Boot Admin client config
        url: http://localhost:9111 # Server connection address
        username: admin # Server username
        password: admin # Server password
        instance:
          prefer-ip: true # Register with IP

# Detailed endpoint monitoring info
management:
  trace:
    http:
      enabled: true
  endpoints:
    web:
      exposure:
        include: "*"
  endpoint:
    health:
      show-details: always
    logfile: # Log file (only if you want to view logs online)
      external-file: ./logs/client-info.log # Log file path

After starting the client, it registers with the server. The UI shows the application list; clicking an instance reveals JVM metrics, thread dumps, HTTP traces, and logs. Logs can be viewed and downloaded directly in the browser.

Microservices Integration with Nacos

Server Configuration

Add the Nacos discovery dependency:

<!-- Nacos registry configuration-->
  <dependency>
      <groupId>com.alibaba.cloud</groupId>
      <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
      <version>2.2.5.RELEASE</version>
  </dependency>

Configure the Nacos server address in YAML:

spring:
  cloud: 
    nacos: 
      discovery:
        server-addr: localhost:8848
        # namespace: # Must match your services' namespace

Client Configuration

Microservice clients do not need the spring-boot-admin-starter-client dependency; the admin server discovers them via the service registry. If a service has a context-path, add metadata so the monitor can reach the actuator endpoints:

spring:
  cloud:
    nacos:
      discovery:
        metadata:  # Monitor context-path config
          management:
            context-path: ${server.servlet.context-path}/actuator

Custom Alerting for Cluster Health

Problem: The default status change notifier only provides the current service's status. In a clustered or multi-instance deployment, you may also want to know the health of other instances of the same service or other services.

Solution: Before sending an alert, call the health check endpoints of other services (e.g., http://localhost:7050/attendance/actuator/nacos-discovery). A successful response means the service is up; an error indicates it is down. Extract the relevant information and include it in the notification.

Result: The alert message now contains the current service status, remaining healthy instances of that service, and the count of other healthy services.