Extended documentation for applicaiton pid monitoring

Author: jkubrynski

spring-boot-docs/src/main/asciidoc/documentation-overview.adoc

@@ -119,7 +119,8 @@ When you're ready to push your Spring Boot application to production, we've got
 * *Monitoring:*
 <<production-ready-features.adoc#production-ready-metrics, Metrics>> |
 <<production-ready-features.adoc#production-ready-auditing, Auditing>> |
-<<production-ready-features.adoc#production-ready-tracing, Tracing>>
+<<production-ready-features.adoc#production-ready-tracing, Tracing>> |
+<<production-ready-features.adoc#production-ready-process-monitoring, Process>>
 
 == Advanced topics
 Lastly, we have a few topics for the more advanced user.

spring-boot-docs/src/main/asciidoc/production-ready-features.adoc

@@ -746,6 +746,34 @@ servlet containers support a uniform Java DSL for customizing the error handling
 
 
 
+[[production-ready-process-monitoring]]
+== Process monitoring
+In Spring Boot Actuator you can find `ApplicationPidListener` which creates file
+containing application PID (by default in application directory and file name is
+`application.pid`). It's not activated by default, but you can do it in two simple
+ways described below.
+
+
+
+[[production-ready-process-monitoring-configuration]]
+=== Extend configuration
+In `META-INF/spring.factories` file you have to activate the listener:
+[indent=0]
+----
+org.springframework.context.ApplicationListener=\
+org.springframework.boot.actuate.system.ApplicationPidListener
+----
+
+
+
+[[production-ready-process-monitoring-programmatically]]
+=== Programmatically
+You can also activate this listener by invoking `SpringApplication.addListeners(...)`
+method and passing `ApplicationPidListener` object. You can also customize file name
+and path through constructor.
+
+
+
 [[production-ready-whats-next]]
 == What to read next
 If you want to explore some of the concepts discussed in this chapter, you can take a