Set up the Server

Running Behind a Front-end Proxy Server

In case the Spring Boot Admin server is running behind a reverse proxy, it may be requried to configure the public url where the server is reachable via (spring.boot.admin.ui.public-url). In addition, when the reverse proxy terminates the https connection, it may be necessary to configure server.forward-headers-strategy=native (also see Spring Boot Reference Guide).

Spring Cloud Discovery

The Spring Boot Admin Server can use Spring Clouds DiscoveryClient to discover applications. The advantage is that the clients don’t have to include the spring-boot-admin-starter-client. You just have to add a DiscoveryClient implementation to your admin server - everything else is done by AutoConfiguration.

Static Configuration using SimpleDiscoveryClient

Spring Cloud provides a SimpleDiscoveryClient. It allows you to specify client applications via static configuration:

pom.xml

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

application.yml

spring:
  cloud:
    discovery:
      client:
        simple:
          instances:
            test:
              - uri: http://instance1.intern:8080
                metadata:
                  management.context-path: /actuator
              - uri: http://instance2.intern:8080
                metadata:
                  management.context-path: /actuator

Other DiscoveryClients

Spring Boot Admin supports all other implementations of Spring Cloud’s DiscoveryClient (Eureka, Zookeeper, Consul, Kubernetes, …​). You need to add it to the Spring Boot Admin Server and configure it properly. An example setup using Eureka is shown above.

Converting ServiceInstances

The information from the service registry are converted by the ServiceInstanceConverter. Spring Boot Admin ships with a default and Eureka converter implementation. The correct one is selected by AutoConfiguration.

tip

You can modify how the information from the registry is used to register the application by using SBA Server configuration options and instance metadata. The values from the metadata takes precedence over the server config. If the plenty of options don’t fit your needs you can provide your own ServiceInstanceConverter.

tip

When using Eureka, the healthCheckUrl known to Eureka is used for health-checking, which can be set on your client using eureka.instance.healthCheckUrl.

Discovery configuration options

Property	Description
spring.boot.admin.discovery.enabled	Enable Spring Cloud Discovery support. Type:  java.lang.Boolean Default:  "true"
spring.boot.admin.discovery.services	Set of serviceIds that has to match to be registered as application. Supports simple patterns (e.g. "foo*", "*foo", "foo*bar"). Default value is everything Type:  java.util.Set<java.lang.String>
spring.boot.admin.discovery.ignored-services	Set of serviceIds to be ignored and not to be registered as application. Supports simple patterns (e.g. "foo*", "*foo", "foo*bar"). Type:  java.util.Set<java.lang.String>
spring.boot.admin.discovery.instances-metadata	Map of metadata that has to be matched by service instance that is to be registered. (e.g. "discoverable=true") Type:  java.util.Map<java.lang.String,java.lang.String>
spring.boot.admin.discovery.ignored-instances-metadata	Map of metadata that has to be matched by service instance that is to be ignored. (e.g. "discoverable=false") Type:  java.util.Map<java.lang.String,java.lang.String>
spring.boot.admin.discovery.converter.health-endpoint-path	Default path of the health-endpoint to be used for the health-url of the discovered service. Type:  java.lang.String Default:  "health"
spring.boot.admin.discovery.converter.health-endpoint-path	Default path of the health-endpoint to be used for the health-url of the discovered service. Type:  java.lang.String Default:  "health"
spring.boot.admin.discovery.converter.health-endpoint-path	Default path of the health-endpoint to be used for the health-url of the discovered service. Type:  java.lang.String Default:  "health"
spring.boot.admin.discovery.converter.management-context-path	Default context-path to be appended to the url of the discovered service for the management-url. Type:  java.lang.String Default:  "/actuator"
spring.boot.admin.discovery.converter.management-context-path	Default context-path to be appended to the url of the discovered service for the management-url. Type:  java.lang.String Default:  "/actuator"
spring.boot.admin.discovery.converter.management-context-path	Default context-path to be appended to the url of the discovered service for the management-url. Type:  java.lang.String Default:  "/actuator"

CloudFoundry

If you are deploying your applications to CloudFoundry then vcap.application.application_id and vcap.application.instance_index must be added to the metadata for proper registration of applications with Spring Boot Admin Server. Here is a sample configuration for Eureka:

application.yml

eureka:
  instance:
    hostname: ${vcap.application.uris[0]}
    nonSecurePort: 80
    metadata-map:
      applicationId: ${vcap.application.application_id}
      instanceId: ${vcap.application.instance_index}

Clustering

Spring Boot Admin Server supports cluster replication via Hazelcast. It is automatically enabled when a HazelcastConfig- or HazelcastInstance-Bean is present. You can also configure the Hazelcast instance to be persistent, to keep the status over restarts. Also have a look at the Spring Boot support for Hazelcast.

1. Add Hazelcast to your dependencies:

pom.xml

<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>hazelcast</artifactId>
</dependency>

2. Instantiate a HazelcastConfig:

HazelcastConfig.java

@Bean
public Config hazelcastConfig() {
    // This map is used to store the events.
    // It should be configured to reliably hold all the data,
    // Spring Boot Admin will compact the events, if there are too many
    MapConfig eventStoreMap = new MapConfig(DEFAULT_NAME_EVENT_STORE_MAP).setInMemoryFormat(InMemoryFormat.OBJECT)
        .setBackupCount(1)
        .setMergePolicyConfig(new MergePolicyConfig(PutIfAbsentMergePolicy.class.getName(), 100));
    // This map is used to deduplicate the notifications.
    // If data in this map gets lost it should not be a big issue as it will atmost
    // lead to
    // the same notification to be sent by multiple instances
    MapConfig sentNotificationsMap = new MapConfig(DEFAULT_NAME_SENT_NOTIFICATIONS_MAP)
        .setInMemoryFormat(InMemoryFormat.OBJECT)
        .setBackupCount(1)
        .setEvictionConfig(
                new EvictionConfig().setEvictionPolicy(EvictionPolicy.LRU).setMaxSizePolicy(MaxSizePolicy.PER_NODE))
        .setMergePolicyConfig(new MergePolicyConfig(PutIfAbsentMergePolicy.class.getName(), 100));
    Config config = new Config();
    config.addMapConfig(eventStoreMap);
    config.addMapConfig(sentNotificationsMap);
    config.setProperty("hazelcast.jmx", "true");
    // WARNING: This setups a local cluster, you change it to fit your needs.
    config.getNetworkConfig().getJoin().getMulticastConfig().setEnabled(false);
    TcpIpConfig tcpIpConfig = config.getNetworkConfig().getJoin().getTcpIpConfig();
    tcpIpConfig.setEnabled(true);
    tcpIpConfig.setMembers(singletonList("127.0.0.1"));
    return config;
}

Hazelcast configuration options

Property	Description
spring.boot.admin.hazelcast.enabled	Enable Hazelcast support. Type:  java.lang.Boolean Default:  "true"
spring.boot.admin.hazelcast.event-store	Name of backing Hazelcast-Map for storing the instance events. Type:  java.lang.String Default:  "spring-boot-admin-application-store"
spring.boot.admin.hazelcast.sent-notifications	Name of backing Hazelcast-Map for storing the sent notifications. Type:  java.lang.String Default:  "spring-boot-admin-sent-notifications"