Spring Boot admin is an application that facilitates monitoring and managing of Spring Boot applications. The latest version of the Spring Boot admin application is not yet compatible with Spring 2.0.0. For the purpose of examples showcased in this section, we have used the Spring Boot 1.5.11 snapshot. The Spring Boot admin version is 1.5.4.
The Spring Boot client applications register themselves with the Spring Boot admin application via HTTP. It is also possible that admin applications discover client applications using the Spring Cloud Eureka discovery service. The Spring Boot admin user interface is built in AngularJS over Actuator endpoints.
That should be enough for the introduction part as examples will provide more insight. Let's build the Spring Boot admin server first.
spring-boot-admin-server is the dependency for building the admin server application. The Spring Boot admin application can have multiple Spring Boot applications registered, so, it becomes necessary for the Spring Boot admin application to be secure. That is the reason we have added the Spring Security starter project dependency. We will incorporate basic authentication for the purpose of this application, but it is not a limitation. We can add advanced security mechanisms, such as OAuth, for securing applications. The following is the POM file for the Spring Boot admin server:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.spring.admin</groupId>
<artifactId>admin-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>admin-server</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.11.BUILD-SNAPSHOT</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-server</artifactId>
<version>1.5.4</version>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-server-ui</artifactId>
<version>1.5.4</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-server-ui-login</artifactId>
<version>1.5.4</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</project>
The application.properties file is where we define the security credentials for accessing the admin application. The following is the contents of the application.properties file:
security.user.name=admin
security.user.password=admin
@EnableAdminServer is provided by the Spring Boot admin server dependency. It indicates that the application works as a Spring Boot admin application. The following is the code for the Spring Boot application main class:
package com.spring.admin.adminserver;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import de.codecentric.boot.admin.config.EnableAdminServer;
@SpringBootApplication
@EnableAdminServer
public class AdminServerApplication {
public static void main(String[] args) {
SpringApplication.run(AdminServerApplication.class, args);
}
}
The next step is to build a sample application that will be registered with the Spring Boot admin application. The following is the POM file:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.11.BUILD-SNAPSHOT</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<spring-boot-admin.version>1.5.7</spring-boot-admin.version>
</properties>
<dependencies>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
</project>
We have to define the following properties:
- spring.boot.admin.url: The URL points to the Spring Boot admin application.
- spring.boot.admin.username: It is necessary for the admin client to access the admin application using security credentials. This property specifies the username for the admin application.
- spring.boot.admin.password: This property specifies the password for the admin application.
- management.security.enabled: This property denotes whether security is enabled for the client application or not.
- security.user.name: This property defines the username for accessing the client application.
- security.user.password: This property specifies the password for accessing the client application.
The following is the application.properties file:
spring.boot.admin.url=http://localhost:8080
server.port=8181
spring.boot.admin.username=admin
spring.boot.admin.password=admin
management.endpoints.web.exposure.include=*
security.user.name=user
security.user.password=password
management.security.enabled=false
The following is the code for the simple Spring Boot application class:
package com.spring.admin.client.bootadminclient;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class BootAdminClientApplication {
public static void main(String[] args) {
SpringApplication.run(BootAdminClientApplication.class, args);
}
}
It is also possible to add customization to default web security configurations provided by Spring Security. The following is an example that demonstrates allowing all requests for authorization:
package com.spring.admin.client.bootadminclient;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
@Configuration
public class SecurityPermitAllConfig extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http.authorizeRequests().anyRequest().permitAll().
and().csrf().disable();
}
}
At this point, we are ready to start both the Spring Boot admin and client applications. When we navigate to the Spring Boot admin application URL, the following screen is shown with a list of all the registered applications:
Clicking on the Details button on the right side of the application name will bring up an interface similar to the one shown here. The Details tab shows the health of the application, memory and JVM statistics, and garbage collector details:
The Logging tab for the application details and displays a list of all the configured loggers. It is possible to change the log level. The following is the interface for Logging:
That's all for the Spring Boot admin application. It provides a production-grade interface and details for monitoring Spring Boot applications. The next section provides performance tuning for Spring Boot applications.