As long as only one version of CF is running using apache as webserver everything is fine, it starts getting complicated when you decide to run e.g. 7 and 8 on one machine using one apache instance. Here you can find a solution how to set it up with different JRun ports which I did once as well (took me hours to find out all these stuff ;-)).
A very nice, quick and dirty solution I came accross some time ago is to use the power of mod_proxy - in this case you tell apache to forward all requests to a different port / URL whatever.
So I did the following:
- Set up CF 7
- Connect CF 7 to apache using the default way
- Set up CF 8 using the internal web server
- Enabled mod_proxy in apache (AddModule / LoadModule)
- Added the following lines in my virtual host configuration for a CF8 host:
ProxyPass / http://127.0.0.1:8500/