spring-boot-graceful-shutdown
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timpeeters
Spring Boot Graceful Shutdown
This project adds graceful shutdown behavior to Spring Boot.
:warning: As of Spring Boot 2.3+, use the native support inside Spring Boot to accomplish graceful shutdown: https://docs.spring.io/spring-boot/docs/current/reference/html/web.html#web.graceful-shutdown. Additionally, when deployed on Kubernetes, add a preStop command: https://docs.spring.io/spring-boot/docs/current/reference/html/deployment.html#deployment.cloud.kubernetes.container-lifecycle
Versions
Multiple branches are maintained to support multiple Spring Boot versions. The following tables show the relation between the Spring Boot version and the Spring Boot Graceful Shutdown version.
| Spring Boot | Spring Boot Graceful Shutdown | Branch |
|---|---|---|
| 1.5.x | 1.0.x | 1.0.x |
| 2.0.x | 2.0.x | 2.0.x |
| 2.1.x | 2.1.x | 2.1.x |
| 2.2.x | 2.2.x | master |
Flow
- The JVM receives the SIGTERM signal and starts shutting down the Spring container.
- A Spring EventListener listens for a ContextClosedEvent and is invoked once the shutdown is started.
- The EventListener updates a Spring Boot HealthIndicator and puts it "out of service".
- The context shutdown is delayed using a Thread.sleep to allow the load balancer to see the updated HealthIndicator status and stop forwarding requests to this instance.
- When the Thread.sleep is finished, the Tomcat container is gracefully shutdown. First by pausing the connector, no longer accepting new request. Next, by allowing the Tomcat thread pool a configurable amount of time to finish the active threads.
- Finally, the Spring context is closed.
Limitations
Currently this project only supports Tomcat as embedded web container for Spring Boot. Undertow and/or Jetty are not yet supported.
Installation
- Add the following Maven dependency:
<dependency>
<groupId>com.github.timpeeters</groupId>
<artifactId>spring-boot-graceful-shutdown</artifactId>
<version>X.X.X</version>
</dependency>
Configuration
| Key | Default value | Description |
|---|---|---|
| graceful.shutdown.enabled | false | Indicates whether graceful shutdown is enabled or not. |
| graceful.shutdown.timeout | 60s | The time to wait for active threads to finish before shutting down the Tomcat connector. |
| graceful.shutdown.wait | 30s | The time to return "out of service" on the health page before starting the graceful shutdown. |
It is important to specify the time unit, otherwise you end up with milliseconds.
Alternative implementations
We found several alternatives for graceful shutdown behavior in Spring Boot.
- https://github.com/SchweizerischeBundesbahnen/springboot-graceful-shutdown
- https://github.com/corentin59/spring-boot-graceful-shutdown
- https://github.com/gesellix/graceful-shutdown-spring-boot
References
- https://github.com/spring-projects/spring-boot/issues/4657
timpeeters