LiveJournal requires mod_perl. It is widely used, so you might already have it on your machine. If not, you can find the official installation docs at http://perl.apache.org/docs/1.0/guide/install.html.
We've found that more people have success when mod_perl is statically linked (“compiled-in” to the Apache module), rather than using a DSO.  This is because it is difficult to build mod_perl reliably as a DSO.
Typically, if you already have a working Apache installation in
and would like to install mod_perl support, then installing the package
libapache-mod-perl should suit your needs. Otherwise,
you should install the package apache-perl.
The apache-perl package provides the advantage of easier
setup, because it is compiled with mod_perl support already.
If you want the LiveJournal code to run as a user other than
what your webserver runs as, then you'll need suEXEC support in
Apache. You are free to figure that out yourself. We will assume
your webserver is running as user
though it does not have to run as any specific user to work.
In fact, the LiveJournal code never writes to disk. So, as long
as it can write to the database (which is essential, obviously),
you can run the code as any user, including
of which are common in out-of-the-box configurations.
You can run the LiveJournal code inside or outside of a
<VirtualHost> section in Apache's
httpd.conf file. However, you are not able
(yet) to have two VirtualHosts running parallel copies of the
code. In the future we will fix that, but for now if you really
need two installations on the same machine, you will need to run
two sets of Apache processes, listening on different ports.
 Consult “ mod_perl Installation User Guide: When DSO Can Be Used” for more information.