recipe.rb

# Configuring Apache Multi-Processing Module
case node[:platform]
  when "centos","redhat","fedora","suse"

    binary_to_use = @node[:apache][:binary]
    if @node[:apache][:mpm] != 'prefork'
      binary_to_use << ".worker"
    end

    template "centos_sysconfig_httpd" do
      source "sysconfig_httpd.erb"
      mode "0644"
      variables({
        :sysconfig_httpd => binary_to_use
      })
      notifies :reload, resources(:service => "apache")
    end
  when "debian","ubuntu"
    package "apache2-mpm-prefork" do
      only_if do @node[:apache][:mpm] == 'prefork' end
    end

    package "apache2-mpm-worker" do
      only_if do @node[:apache][:mpm] != 'prefork' end
    end
end

sysconfig_httpd.erb

# Configuration file for the httpd service.

#
# The default processing model (MPM) is the process-based
# 'prefork' model.  A thread-based model, 'worker', is also
# available, but does not work with some modules (such as PHP).
# The service must be stopped before changing this variable.
#
#HTTPD=/usr/sbin/httpd.worker
HTTPD=<%= @sysconfig_httpd %>
#
# To pass additional options (for instance, -D definitions) to the
# httpd binary at startup, set OPTIONS here.
#
#OPTIONS=

#
# By default, the httpd process is started in the C locale; to
# change the locale in which the server runs, the HTTPD_LANG
# variable can be set.
#
#HTTPD_LANG=C