This has been a relatively long process to figure out how best to configure a Jetty/eXist instance to run happily alongside others, on a test domain, and how to test that setup. This is what I've done:

• Install apache locally from the repos.
• Install mod_jk from the repos.
• Turn on SSL (sudo a2enmod ssl) and set up a self-signed cert (lots of docs on this available).
• Set up test domains in the local hosts file:

  127.0.0.1	localhost
  127.0.1.1	spud
  127.0.2.1	test-internal.hcmc.uvic.ca
  127.0.3.1	moeml-internal.hcmc.uvic.ca
  

• Set up virtual domains in Apache -- example sites-enabled/test.conf:

  <VirtualHost 127.0.2.1:80>
  	ServerAdmin webmaster@localhost
  	ServerName test-internal.hcmc.uvic.ca
  	ServerAlias test
  	ProxyRequests Off
  	<Proxy *>
  		Order deny,allow
  		Allow from all
  	</Proxy>
  	ProxyPreserveHost on
  	ProxyPass / http://test-internal.hcmc.uvic.ca:8080/ nocanon
          ProxyPassReverse / http://test-internal.hcmc.uvic.ca:8080
          AllowEncodedSlashes NoDecode
  </VirtualHost>
  
  <VirtualHost 127.0.2.1:443>
          ServerAdmin webmaster@localhost
          ServerName test-internal.hcmc.uvic.ca
          ServerAlias test
          SSLEngine on
          SSLCertificateFile /etc/ssl/certs/spud.crt
          SSLCertificateKeyFile /etc/ssl/private/spud.key
          ProxyRequests Off
          <Proxy *>
                  Order deny,allow
                  Allow from all
          </Proxy>
          ProxyPreserveHost on
          ProxyPass / http://test-internal.hcmc.uvic.ca:8080/ nocanon
          ProxyPassReverse / http://test-internal.hcmc.uvic.ca:8080
          AllowEncodedSlashes NoDecode
  </VirtualHost>
  

• In these four files in the Jetty instance:

  tools/jetty/etc/jetty-http.xml
  tools/jetty/etc/jetty-ssl.xml
  tools/jetty/etc/standalone-jetty-http.xml
  tools/jetty/etc/standalone-jetty-ssl.xml
  

  change the <Set name="host"> to <Set name="host">test-internal.hcmc.uvic.ca</Set>. (I think only the first two matter for our purposes, but it does no harm to change the others.)
• Start the Jetty instance, and restart apache. Access the jetty app on test-internal.hcmc.uvic.ca.

I still have to test this with a second Jetty running side-by-side on a different domain; I'll do that tomorrow.