Jetty is throwing `Unknown module' error when running with --add-to-start - jetty

Question

I am trying to configure Jetty and facing this:
root#jans-dev:~/jetty-base# java -jar $JETTY_HOME/start.jar --add-to-start=http,deploy
ERROR : Unknown module='http'. List available with --list-modules
Usage: java -jar $JETTY_HOME/start.jar [options] [properties] [configs]
java -jar $JETTY_HOME/start.jar --help # for more information
Background:
Jetty 9.4 installed as root on an lxc container on Ubuntu using sudo apt install jetty9
Jetty service is running and I can access default landing page
Jetty home is set to export JETTY_HOME=/usr/share/jetty
Jetty base is set to export JETTY_BASE=/root/jetty-base
I have executed below command successfully before trying to add modules.
root#jans-dev:~/jetty-base# java -jar $JETTY_HOME/start.jar --create-startd
MKDIR : ${jetty.base}/start.d
INFO : Base directory was modified
Also, when I run --list-modules, it is coming up empty:
root#jans-dev:~/jetty-base# java -jar $JETTY_HOME/start.jar --list-modules
Available Modules:
==================
tags: [-internal]
Enabled Modules:
================
root#jans-dev:~/jetty-base#
I am not sure what am I missing here. How do I make modules available to Jetty? I have also checked this reference

Answer 1

Sounds like your linux distro has mangled the jetty distribution.
Does your /usr/share/jetty directory contain the directories etc/, lib/, and modules/? If not, then that's not a valid ${jetty-home}.
Perhaps your linux distribution put the jetty-home somewhere else?
But that would also be invalid, as the start.jar should be in the same directory as those other directories.
Example of what a proper ${jetty.home} looks like ...
$ ls -la jetty-home-9.4.44.v20210927
total 776
drwxr-xr-x 6 joakim joakim 4096 Sep 27 18:12 ./
drwxr-xr-x 74 joakim joakim 12288 Nov 2 15:32 ../
drwxr-xr-x 2 joakim joakim 4096 Oct 7 10:07 bin/
drwxr-xr-x 4 joakim joakim 4096 Oct 14 07:17 etc/
drwxr-xr-x 14 joakim joakim 4096 Oct 7 10:07 lib/
-rw-r--r-- 1 joakim joakim 30012 Sep 27 18:12 license-eplv10-aslv20.html
drwxr-xr-x 22 joakim joakim 4096 Oct 7 10:07 modules/
-rw-r--r-- 1 joakim joakim 6262 Sep 27 18:12 notice.html
-rw-r--r-- 1 joakim joakim 163958 Sep 27 18:10 start.jar
-rw-r--r-- 1 joakim joakim 550572 Sep 27 17:44 VERSION.txt
In the past, there were Linux Distributions that tried to put the various Jetty libs (The jar files in ${jetty.home}/lib/) in their distribution setup as separate dependencies, but that's not a valid setup for a modular Servlet/Web Container like Jetty. Most distributions have realized this and have reverted to a sane setup now.
The fastest fix for you is to remove this bad Jetty package from your linux distribution and just download and use the official tarball.
https://search.maven.org/artifact/org.eclipse.jetty/jetty-home
https://www.eclipse.org/jetty/download.php