I'd like to be able to have multiple distributions, say Fedora and Debian, both sharing an Apache DocumentRoot. For example, I could have the same partition mounted to /var/www in both distributions. I can't find any examples of others doing this, so perhaps its unwise.
What are some negative consequences of doing this? Is there a different way to achieve the same goal?
As long as this is for the static files to save space you will be fine.
If you have programs under /var/www (e.g. using WSGIScriptAlias) I suggest you separate these out to physical locations outside of /var/www on a machine by machine basis. The distributions often differ in subtle ways that need to be reflected in your programs.
You will most likekly have to do such separation if the programs save data in some (sub-director) of the program location.
As you say, simply move your /var/www to a partition and mount this partition as /var/www on every distribution.
You may have permission issues if one distro runs apache under a different user/group to another, but that's a trivial fix in the apache conf file.
Also, if you do install Fedora (or any other distro running SELinux) and make changes within /var/www on a (for example) Debian distro then when you return to Fedora you may have SELinux issues to contend with.
