Tag Archives: apache2.4

Apache MaxClients and ServerLimit on Centos 7 and Ubuntu 14.04

In Apache 2.4 (which is in Centos 7 and Ubuntu 14.04 default) the mpm_worker MaxClients has been replaced with MaxRequestWorkers.

In Ubuntu 14.04 you can see the below in /etc/apache2/mods-enabled/mpm_prefork.conf

<IfModule mpm_prefork_module>
StartServers 5
MinSpareServers 5
MaxSpareServers 10
MaxRequestWorkers 150
MaxConnectionsPerChild 500
ServerLimit 300
</IfModule>

In Centos 7 however there is NO configuration for this, which means it’s at the default value of 256 unless set by the user. This also means that StartServers is set by default to 3, MinSpareServers is set to 5, and MaxSpareServers is 10.
To configure Centos and set some limits, you need to edit this file /etc/httpd/conf.modules.d/00-mpm.conf appending the above content.

Always verify with apachectl -t or  httpd -t if all is ok before reloading/restarting Apache.

NOTE1: ServerLimit is not in the default configurations for either Centos 7 or Ubuntu 14.04 which means that if you set MaxRequestWorkers above 256, you must remember to add ServerLimit!

NOTE2: MaxConnectionsPerChild set to 0 on Ubuntu 14.04, and 0 is also the default in Centos 7. This means that on both the Apache processes will not expire. This is going to be bad for users who like to set their php memory_limit to 1G!

Fullstatus Apache 2.4 Centos7

Apache on CentOS 7 doesn’t come with any configuration for enabling /server-status
The module does come by default though, so to get this going, all you need to do is:

$ cat >> /etc/httpd/conf.modules.d/01-status.conf << EOF
<Location /server-status>
SetHandler server-status
Require local
</Location>
EOF

$ systemctl reload httpd
$ apachectl fullstatus

Apache 2.4 + PHP-FPM Ubuntu 14.04 

apt-get install php5-mysql php5-fpm php5-gd php5-cli apache2-mpm-worker libapache2-mod-fastcgi

Create a php-fpm pool /etc/php5/fpm/pool.d/$USER.cnf

[$USER]
user = $USER
group = www-data
listen = 127.0.0.1:9000
listen.owner = www-data
listen.group = www-data

pm = dynamic
pm.max_children = 100
pm.start_servers = 35
pm.min_spare_servers = 15
pm.max_spare_servers = 35
php_value[session.save_handler] = files
php_value[session.save_path] = /var/lib/php/session/$USER
chdir = /

In Vhost:

ProxyPassMatch ^/(.*\.php(/.*)?)$ fcgi://127.0.0.1:9000/var/www/vhosts/MYDOMAIN.COM/public_html/$1

Enable/disable modules and restart services

a2dismod mpm_prefork php5 && a2enmod actions fastcgi alias mpm_event proxy_fcgi proxy

service php5-fpm restart
service apache2 restart

Don’t forget to enable “index.php” in your DirectoryIndex directive, if using PHP-FPM! Also, remove any PHP directives from Apache, and configure in PHP-FPM instead.