Status providers

Under Spring Boot

When using the autoconfiguration class, SystemdNotifyStatusProvider beans will also be searched in the application context and used to compose an extended status message that systemd will display when using the status verb.

Out of the box this module will show memory (heap/non-heap), classloader information, application startup sequence state and bean creation progress.

Additionally, if running with the embedded Tomcat container, status regarding Tomcat's connectors will also be displayed.

[root@machine ~]# systemctl status myservice.service
● myservice.service - My Spring Boot Service
   Loaded: loaded (/etc/systemd/system/myservice.service; disabled; vendor preset: disabled)
   Active: active (running) since Qui 2018-02-15 10:19:28 WET; 1h 24min ago
 Main PID: 11142 (java)
   Status: "Heap: 139.5 MiB/256 MiB, Non-heap: 62.7 MiB/64.1 MiB, Classes: 7915"
   CGroup: /system.slice/myservice.service
           └─11142 /opt/jdk17/bin/java -XX:+ExitOnOutOfMemoryError -jar /opt/myservice/myservice.jar

Regular Java application

After creating the Systemd instance to interface with the service supervisor, register any instance of SystemdNotifyStatusProvider with addStatusProviders.

The following table lists the provided implementations:

See the Startup progress page for more information regarding SystemdApplicationRunStatusProvider and SystemdApplicationContextStatusProvider.

See the Tomcat status page for more information regarding SystemdTomcatStatusProvider.

Custom status providers

You can create your own status information extending SystemdNotifyStatusProvider, and provide an instance of such custom classes to systemd

• if using your own managed instance of Systemd, by using addStatusProviders
• under Spring Boot, by registering it as a bean in any configuration class:

@Configuration
@ConditionalOnSystemD
public class MyConfiguration {
  
  @Bean
  MyStatusProvider myStatusProvider() {
    return new MyStatusProvider();
  }
}

In the example above, the configuration class does not need to be annotated with ConditionalOnSystemd, because these beans are harmless even when not running under systemd. However, this was these extra resources do not have to be built at all. Check the Conditionals page for more information.

Under Spring Boot you can also autowire the current instance of Systemd and programmatically manage it:

@Configuration
@ConditionalOnSystemD
public class MyConfiguration {
  
  @Autowire
  MyConfiguration(Systemd systemd) {
    // Force update current service status
    systemd.updateStatus();
  }
}

Out of the box, Systemd sends status updates to the supervisor daemon once every five seconds.