Updated documentation for recent jetty image changes

jetty/content.md

@@ -8,7 +8,7 @@ Jetty is a pure Java-based HTTP (Web) server and Java Servlet container. While W
 
 # How to use this image.
 
-Run the default Jetty server (`CMD ["jetty.sh", "run"]`):
+Run the default Jetty server (`CMD ["java","-Djava.io.tmpdir=/tmp/jetty","-jar","/usr/local/jetty/start.jar"]`):
 
 ```console
 $ docker run -d %%REPO%%:9
@@ -26,10 +26,10 @@ The default Jetty environment in the image is:
 
 	JETTY_HOME    =  /usr/local/jetty
 	JETTY_BASE    =  /var/lib/jetty
-	JETTY_CONF    =  /usr/local/jetty/etc/jetty.conf
-	JETTY_STATE   =  /run/jetty/jetty.state
-	JETTY_ARGS    =
-	JAVA_OPTIONS  =
+	JETTY_CONF    =  /usr/local/jetty/etc/jetty.conf # Deprecated
+	JETTY_STATE   =  /run/jetty/jetty.state          # Deprecated
+	JETTY_ARGS    =                                  # Deprecated
+	JAVA_OPTIONS  =                                  # Deprecated
 	TMPDIR        =  /tmp/jetty
 
 ## Deployment
@@ -38,6 +38,24 @@ Webapps can be [deployed](https://www.eclipse.org/jetty/documentation/current/qu
 
 For older EOL'd images based on Jetty 7 or Jetty 8, please follow the [legacy instructions](https://wiki.eclipse.org/Jetty/Howto/Deploy_Web_Applications) on the Eclipse Wiki and deploy under `/usr/local/jetty/webapps` instead of `/var/lib/jetty/webapps`.
 
+## Configuration
+
+The configuration of the jetty server can be reported by running with the --list-config option:
+```console
+$ docker run -d %%REPO%%:9 --list-config
+```
+Configuration such as parameters and additional modules may also be passed in via the command line. For example
+```console
+$ docker run -d %%REPO%%:9 --modules=jmx jetty.threadPool.maxThreads=500
+```
+To update the server configuration in a new docker image, the Dockerfile may enamble additional modules with RUN commands like:
+```
+WORKDIR $JETTY_BASE
+RUN java -jar "$JETTY_HOME/start.jar" --add-to-startd=jmx,http2
+```
+Modules may be configured in a Dockerfile by editing the properties in corresponding `/var/lib/jetty/start.d/*.mod` file or the module can be deactivated by
+removing that file.
+
 ## Read-only container
 
 To run `%%REPO%%` as a read-only container, have Docker create the `/tmp/jetty` and `/run/jetty` directories as volumes: