mdsh.com/wiki

On Ubuntu (at least with 10.04 LTS) Tomcat is very easy to install
sudo apt-get install tomcat6 libtcnative-1
It is nicely setup with CATALINA_HOME=/usr/share/tomcat6 and
CATALINA_BASE=/var/lib/tomcat6
That's great - but I like my config files to live on the same NFS mount as the web sites, which gets mounted onto /usr/local/sites.

The config files live in
$CATALINA_BASE/conf which in Ubunto would therefore be
/var/lib/tomcat6/conf

But since that folder is actually just a sym-link to
/etc/tomcat6 it is very easy to swap Ubuntu's default location for my preferred location...
sudo service tomcat6 stop
cd /var/lib/tomcat6/
sudo rm conf
sudo ln -sf /usr/local/sites/etc/tomcat/conf/ conf
sudo service tomcat6 start
We haven't lost anything - it's easy to put the sym link back to its default location if needed.

Ubuntu:Tomcat is mentioned on: Tomcat | Linux