Document a warning about embedded Tomcat and tmpwatch on CentOS

Closes gh-5009

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

@@ -2252,6 +2252,13 @@ Spring Boot includes support for embedded Tomcat, Jetty, and Undertow servers. M
 developers will simply use the appropriate '`Starter`' to obtain a fully configured
 instance. By default the embedded server will listen for HTTP requests on port `8080`.
 
+WARNING: If you choose to use Tomcat on CentOS be aware that, by default, a temporary
+directory is used to store compiled JSPs, file uploads etc. This directory may be
+deleted by `tmpwatch` while your application is running leading to failures. To avoid
+this, you may want to customize your `tmpwatch` configuration so that `tomcat.*`
+directories are not deleted, or configure `server.tomcat.basedir` so that embedded Tomcat
+uses a different location.
+
 
 
 [[boot-features-embedded-container-servlets-filters-listeners]]