Apache – How to enable mod_proxy_ajp for Apache 2.2.14

In versions prior to 2.4, you cannot change the MPM of the binary Apache2 installation at run-time.

You have to compile Apache with the desired MPM using the --with-mpm=MODULE NAME command line option to the config script. To change MPM, the binary must be rebuilt.

You can determine which MPM Apache2 is currently built with by executing apache2 -l or httpd -l on the command line.

Brief but very clear documentation on this:

http://httpd.apache.org/docs/2.2/mpm.html

In version 2.4, you can also build MPMs as dynamic modules which allows changing the MPM at run-time.

http://httpd.apache.org/docs/2.4/mpm.html#dynamic