Jetty allows for deploying an arbitrary context or web application by monitoring a directory for changes. If a web application or a context descriptor is added to the directory, Jetty’s DeploymentManager (DM) deploys a new context. If a context descriptor is touched or updated, the DM stops, reconfigures, and redeploys its context. If a context is removed, the DM stops it and removes it from the server.

This behavior can be controlled by configuring WebAppProvider properties.

The default location for this configuration is in the ${jetty.home}/etc/jetty-deploy.xml file. To modify it as part of the Jetty distribution, first enable the deploy module. Once it is enabled, you can edit these properties in either the $JETTY_BASE/start.d/deploy.ini or $JETTY_BASE/start.ini file, depending on how your implementation is configured.

<?xml version="1.0"?>
# ---------------------------------------
# Module: deploy
# Enables webapplication deployment from the webapps directory.
# ---------------------------------------
--module=deploy

# Monitored directory name (relative to $jetty.base)
# jetty.deploy.monitoredDir=webapps
# - OR -
# Monitored directory path (fully qualified)
# jetty.deploy.monitoredPath=/var/www/webapps

# Defaults Descriptor for all deployed webapps
# jetty.deploy.defaultsDescriptorPath=${jetty.base}/etc/webdefault.xml

# Monitored directory scan period (seconds)
# jetty.deploy.scanInterval=1

# Whether to extract *.war files
# jetty.deploy.extractWars=true

See Understanding the Default WebAppProvider for more configuration details.

See also Deployment Architecture for detailed conceptual information.