About
jetty.base is the jetty configuration directory.
This is where the etc, webapps and start files will be looked for.
If not found in jetty.base, they are looked for in jetty.home.
A Jetty base directory allows the configuration and web applications of a server instance to be stored separately from the Jetty distribution, so that upgrades can be done with minimal disruption.
It defines the location of a specific implementation of a Jetty server, its configuration, logs and web applications (typically start.d/*.ini files, logs and webapps).
The Jetty - Getting started (Hello World) a fully-functioning Jetty Base complete with numerous web applications demonstrating different Jetty functionality.
Articles Related
Set
Set as property
jetty.base=[directory]
or env variable JETTY_BASE