Spring Boot Admin – Spring Boot Admin 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).

Configuration Options

Property name	Description	Default value
spring.boot.admin.server.enabled	Enables the Spring Boot Admin Server.	`true`
spring.boot.admin.context-path	The context-path prefixes the path where the Admin Server’s statics assets and API should be served. Relative to the Dispatcher-Servlet.
spring.boot.admin.monitor.status-interval	Time interval to check the status of instances.	10,000ms
spring.boot.admin.monitor.status-max-backoff	The maximal backoff for status check retries (retry after error has exponential backoff, minimum backoff is 1 second).	60,000ms
spring.boot.admin.monitor.status-lifetime	Lifetime of status. The status won’t be updated as long the last status isn’t expired.	10,000ms
spring.boot.admin.monitor.info-interval	Time interval to check the info of instances.	1m
spring.boot.admin.monitor.info-max-backoff	The maximal backoff for info check retries (retry after error has exponential backoff, minimum backoff is 1 second).	10m
spring.boot.admin.monitor.info-lifetime	Lifetime of info. The info won’t be updated as long the last info isn’t expired.	1m
spring.boot.admin.monitor.default-timeout	Default timeout when making requests. Individual values for specific endpoints can be overridden using `spring.boot.admin.monitor.timeout.*`.	10,000
spring.boot.admin.monitor.timeout.*	Key-Value-Pairs with the timeout per endpointId. Defaults to default-timeout.
spring.boot.admin.monitor.default-retries	Default number of retries for failed requests. Modifying requests (`PUT`, `POST`, `PATCH`, `DELETE`) are never retried. Individual values for specific endpoints can be overridden using `spring.boot.admin.monitor.retries.*`.	0
spring.boot.admin.monitor.retries.*	Key-Value-Pairs with the number of retries per endpointId. Defaults to default-retries. Modifying requests (`PUT`, `POST`, `PATCH`, `DELETE`) are never retried.
spring.boot.admin.metadata-keys-to-sanitize	Metadata values for the keys matching these regex patterns will be sanitized in all json output. Starting from Spring Boot 3, all actuator values are masked by default. Take a look at the Spring Boot documentation in order to configure unsanitizing of values (Sanitize Sensitive Values).	`".password$", ".secret$", ".key$", ".token$", ".credentials.", ".*vcap_services$"`
spring.boot.admin.probed-endpoints	For Spring Boot 1.x client applications SBA probes for the specified endpoints using an OPTIONS request. If the path differs from the id you can specify this as id:path (e.g. health:ping)..	`"health", "env", "metrics", "httptrace:trace", "threaddump:dump", "jolokia", "info", "logfile", "refresh", "flyway", "liquibase", "heapdump", "loggers", "auditevents"`
spring.boot.admin.instance-auth.enabled	Enable pulling credentials from spring configuration properties	`true`
spring.boot.admin.instance-auth.default-user-name	A default user name used to authenticate to registered services. The `spring.boot.admin.instance-auth.enabled` property must be `true`.	`null`
spring.boot.admin.instance-auth.default-password	A default user password used to authenticate to registered services. The `spring.boot.admin.instance-auth.enabled` property must be `true`.	`null`
spring.boot.admin.instance-auth.service-map.*.user-name	A user name used to authenticate to the registered service with the specified name. The `spring.boot.admin.instance-auth.enabled` property must be `true`.
spring.boot.admin.instance-auth.service-map.*.user-password	A user password used to authenticate to the registered service with the specified name. The `spring.boot.admin.instance-auth.enabled` property must be `true`.
spring.boot.admin.instance-proxy.ignored-headers	Headers not to be forwarded when making requests to clients.	`"Cookie", "Set-Cookie", "Authorization"`
spring.boot.admin.ui.public-url	Base url to use to build the base href in the ui.	If running behind a reverse proxy (using path rewriting) this can be used to make correct self references. If the host/port is omitted it will be inferred from the request.
spring.boot.admin.ui.brand	Brand to be shown in the navbar.	`"<img src="assets/img/icon-spring-boot-admin.svg"><span>Spring Boot Admin</span>"`
spring.boot.admin.ui.title	Page-Title to be shown.	`"Spring Boot Admin"`
spring.boot.admin.ui.login-icon	Icon used as image on login page.	`"assets/img/icon-spring-boot-admin.svg"`
spring.boot.admin.ui.favicon	Icon used as default favicon and icon for desktop notifications.	`"assets/img/favicon.png"`
spring.boot.admin.ui.favicon-danger	Icon used as favicon when one or more service is down and for desktop notifications.	`"assets/img/favicon-danger.png"`
spring.boot.admin.ui.remember-me-enabled	Switch to show/hide the remember-me checkbox on the login page.	`true`
spring.boot.admin.ui.poll-timer.cache	Polling duration in ms to fetch new cache data.	`2500`
spring.boot.admin.ui.poll-timer.datasource	Polling duration in ms to fetch new datasource data.	`2500`
spring.boot.admin.ui.poll-timer.gc	Polling duration in ms to fetch new gc data.	`2500`
spring.boot.admin.ui.poll-timer.process	Polling duration in ms to fetch new process data.	`2500`
spring.boot.admin.ui.poll-timer.memory	Polling duration in ms to fetch new memory data.	`2500`
spring.boot.admin.ui.poll-timer.threads	Polling duration in ms to fetch new threads data.	`2500`
spring.boot.admin.ui.poll-timer.logfile	Polling duration in ms to fetch new logfile data.	`1000`
spring.boot.admin.ui.enable-toasts	Allows to enable toast notifications.	`false`

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.

	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`.

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

Table 1. Instance metadata options
Key	Value	Default value
user.name user.password	Credentials being used to access the endpoints.
management.scheme	The scheme is substituted in the service URL and will be used for accessing the actuator endpoints.
management.address	The address is substituted in the service URL and will be used for accessing the actuator endpoints.
management.port	The port is substituted in the service URL and will be used for accessing the actuator endpoints.
management.context-path	The path is appended to the service URL and will be used for accessing the actuator endpoints.	`${spring.boot.admin.discovery.converter.management-context-path}`
health.path	The path is appended to the service URL and will be used for the health-checking. Ignored by the `EurekaServiceInstanceConverter`.	`${spring.boot.admin.discovery.converter.health-endpoint}`
group	The group is used to group services in the UI by the group name instead of application name.

Table 2. Discovery configuration options
Property name	Description	Default value
spring.boot.admin.discovery.enabled	Enables the DiscoveryClient-support for the admin server.	`true`
spring.boot.admin.discovery.converter.management-context-path	Will be appended to the service-url of the discovered service when the management-url is converted by the `DefaultServiceInstanceConverter`.	`/actuator`
spring.boot.admin.discovery.converter.health-endpoint-path	Will be appended to the management-url of the discovered service when the health-url is converted by the `DefaultServiceInstanceConverter`.	`"health"`
spring.boot.admin.discovery.ignored-services	This services will be ignored when using discovery and not registered as application. Supports simple patterns (e.g. "foo", "bar", "foobar").
spring.boot.admin.discovery.services	This services will be included when using discovery and registered as application. Supports simple patterns (e.g. "foo", "bar", "foobar").	`"*"`
spring.boot.admin.discovery.ignored-instances-metadata	Instances of services will be ignored if they contain at least one metadata item that matches this list. (e.g. "discoverable=false")
spring.boot.admin.discovery.instances-metadata	Instances of services will be included if they contain at least one metadata item that matches this list. (e.g. "discoverable=true")

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.

Add Hazelcast to your dependencies:

pom.xml

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

Instantiate a HazelcastConfig:

@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;
}

Table 3. Hazelcast configuration options
Property name	Description	Default value
spring.boot.admin.hazelcast.enabled	Enables the Hazelcast support	`true`
spring.boot.admin.hazelcast.event-store	Name of the Hazelcast-map to store the events	`"spring-boot-admin-event-store"`
spring.boot.admin.hazelcast.sent-notifications	Name of the Hazelcast-map used to deduplicate the notifications.	`"spring-boot-admin-sent-notifications"`