No apache MPM package installed error

In looking at the documentation at http://httpd.apache.org, I found that the virtual host is a core option. MPM is a process/thread management issue within the apache web server. Having or not having MPM should not be a determining factor in the support of virtual hosts.

My guess therefore is that there are directives contained within your httpd.conf file are not consistent with the type of MPM modules are compiled into the apache server. For instance, you might be using the prefork MPM but the directives in the httpd.conf file would contain something like ThreadsperChild which is not appropriate. This could be the source of your error message.

The Apache documentation further indicates that depending on the platform, there is a default MPM always selected by the configure process you go through. In Linux it is prefork.

sudo apt-get install apache2

Seems the latest debian upgrade broke this again, so here's a quick fix for anyone coming to this from google for the latest repeat of this issue:

apt-get install apache2-mpm-prefork
cd /etc/apache2/mods-enabled
ln -s ../mods-available/mpm_prefork.* ./
/etc/init.d/apache2 restart

(prefix with sudo as appropriate if you're not root)

If you compiled it from source on Linux the default prefork mpm should have been installed. You should be able to list all modules including mpm's by running httpd -l. See the MPM documentation for more details