Error starting apache, httpd: Configuration error: More than one MPM loaded

Question

I get the following when I try to start the apache server, I built the 2.4.6 version and have placed in a local location.

[apacheas@twproxy1 bin]$ ./apachectl -k start
AH00534: httpd: Configuration error: More than one MPM loaded.

Based on some information provided on some sites, I tries to list down the modules available (not sure!) as below.

[apacheas@twproxy1 bin]$ ./httpd -l

Compiled in modules:
  core.c
  mod_so.c
  http_core.c
  event.c

What could be going wrong?

This is related to the recent Heart Bleed bug in openssl -- for which we were advised to upgrade both apache and openssl version. We did all, but stuck with the above problem/

Answer 1

Check all your enabled mods inside mods-enabled directory. If you already enabled mpm_prefork, you should disable the worker module.

sudo a2dismod worker

sudo service apache2 restart

Answer 2

Look in: /etc/httpd/conf.modules.d

You'll find a file called: 00-mpm.conf

You can uncomment only one out of those 3 lines:

LoadModule mpm_prefork_module modules/mod_mpm_prefork.so
#LoadModule mpm_worker_module modules/mod_mpm_worker.so
#LoadModule mpm_event_module modules/mod_mpm_event.so

More informations here : https://httpd.apache.org/docs/2.4/mpm.html