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mod_proxy_balancer requires the service of mod_proxy, and it provides load balancing for all the supported protocols.


mod_proxy_balancer has following scheduling algorithm

  • mod_lbmethod_byrequests
  • mod_lbmethod_bytraffic
  • mod_lbmethod_bybusyness
  • mod_lbmethod_heartbeat


Followings are the example of a balancer configuration:

<Proxy "balancer://mycluster">
    BalancerMember "http://192.168.1.50:80"
    BalancerMember "http://192.168.1.51:80"
</Proxy>
ProxyPass        "/test" "balancer://mycluster"
ProxyPassReverse "/test" "balancer://mycluster"

Followings are another example of balancer configuration:

<VirtualHost *:80>
        ServerName cdn.foo.net

        ProxyRequests   Off
        ProxyVia        Off
        ProxyPreserveHost       On

        <Proxy *>
                Require all granted
        </Proxy>

       <Proxy balancer://mycluster>
           BalancerMember http://192.168.10.7:80 route=1 connectiontimeout=1
           BalancerMember http://192.168.10.8:80 route=2 connectiontimeout=1

           ProxySet lbmethod=byrequests
           ProxySet stickysession=ROUTEID
       </Proxy>
       ProxyPass               "/"     "balancer://mycluster"
       ProxyPassReverse        "/"     "balancer://mycluster"

        DocumentRoot "/pub/cdn.qsok.com/"
        CustomLog /var/log/httpd/cdn.its-newid.net-access.log combined
        ErrorLog /var/log/httpd/cdn.its-newid.net-error.log
</VirtualHost>

If you encounter errors like below in case that you use PHP combined with Apache, you will need to use other configuration. Probably you may not able to get any session data from your client.

Below configuration will enable you to use your PHP codes as designed.

<VirtualHost *:80>
        ServerName cdn.foo.net

        ProxyRequests   Off
        ProxyVia        Off
        ProxyPreserveHost       On

        <Proxy *>
                Require all granted
        </Proxy>

        ProxyPass       /balancer-manager       !
        ProxyPass       /       balancer://mycluster/   stickysession=BALANCEID nofailover=On
        ProxyPassReverse        /       http://192.168.10.7:80
        ProxyPassReverse        /       http://192.168.10.8:80
       <Proxy balancer://mycluster>
           BalancerMember http://192.168.10.7:80   route=1 connectiontimeout=1
           BalancerMember http://192.168.10.8:80   route=2 connectiontimeout=1
           ProxySet lbmethod=byrequests
       </Proxy>

        <Location /balancer-manager>
                SetHandler balancer-manager
                Order deny,allow
                Allow from all
        </Location>

        DocumentRoot "/pub/cdn.qsok.com/"
        CustomLog /var/log/httpd/cdn.its-newid.net-access.log combined
        ErrorLog /var/log/httpd/cdn.its-newid.net-error.log
</VirtualHost>