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Load balancing with APACHE web server

This article provides steps that are needed to configure load balancer while setting up a clustered environment in a distributed network. However, this should not be considered a full and final configuration for a full-fledged production stable configuration. To make a production stable load balancing server, several configurations need to be done.

This is just an illustration of how the basic configuration can be carried out with limited resource availability.


  • Server 1: Exposed a web service or open for web requests.
  • Server 2: Expose a web service that is open for web request and also hosts a apache load balancer
  • Server 1 and 2 are running on a separate IPs
  • HTTP Port on Server 1: 8091
  • HTTP Port on Server 2: 8091
  • Apache HTTPD server port: 8090 setup on Server 2


  • Server 1 setup for hosting SOAP service exposed on mule server with following
    URI: http://<>:8091/hello?wsdl
  • Server 2 setup for hosting SOAP service exposed on mule server with following
    URI: http://<>:8091/hello?wsdl
  • Apache httpd server configured on Server 2

Sequence of operation

  • Create and run web service on Server 1
  • Create and run web service on Server 2
  • Install and configure HTTPD Server as LB instance
    • Configure httpd-proxy-balance.conf
    • Configure httpd.conf
  • Assert LB activity

Detailed Steps to setup LB

Create and run web service on Server 1(in this case it is on

  • Create a soap based mule web service as shown in the “Message Flow” diagram given below

Load balancing with APACHE web server
  • Following is the XML Configuration fie (Watch out that the service is exposed over
    <flow name="soap-web-serviceFlow1" doc:name="soap-web-serviceFlow1">
<http:inbound-endpoint address="http://localhost:8091/hello"
exchange-pattern="request-response" doc:name="HTTP">
<cxf:jaxws-service serviceClass="org.example.HelloWorld" />
<component class="org.example.HelloWorldImpl" doc:name="Java" />
  • Run the service with following configuration

Load balancing with APACHE web server
  • Add following run time parameter at VM arguments -Dmule.tcp.bindlocalhosttoalllocalinterfaces=true, this should look like

Load balancing with APACHE web server
  • With this, the service will be exposed

Create and run another web service on Server 2 (in this case it on

  •  Repeat the same steps similar to the ones done on Server 1
  • Finally the exposed web service should have a URI,

Now that we have 2 services running on 2 different servers, configuration of LB for these servers can be done.

Install and configure HTTPD Server as LB instance

  • Download and install apache httpd server. (If already exists, then skip to next step). This can be downloaded from
  • Configure httpd-proxy-balance.conf
    • Required to keep this file under ‘conf/extra/’ folder
    • httpd-proxy-balance.conf should look like
<IfModule mod_proxy_balancer.c>
ProxyRequests off
<Location /balancer-manager>
Set Handler balancer-manager
Order deny,allow
Allow from all
ProxyPass /balancer-manager !
ProxyPass / balancer://mycluster/ stickysession=SESSION_ID
<Proxy balancer://mycluster >
BalancerMember loadfactor=4 route=node1
BalancerMember loadfactor=6 route=node2
# Load Balancer Settings
# We will be configuring a simple Round
# Robin style load balancer. This means
# that all webheads take an equal share of
# of the load.
ProxySet lbmethod=byrequest
  • Configure httpd.conf
  • Make sure they are uncommented following modules

LoadModule lbmethod_byrequests_module modules/
LoadModule log_config_module modules/
LoadModule proxy_balancer_module modules/
LoadModule proxy_http_module modules/
LoadModule slotmem_shm_module modules/
LoadModule proxy_module modules/

  • Add this line

Include conf/extra/httpd-proxy-balancer.conf

  • Save and restart, httpd

Assert LB activity

  • Point at the browser, and access http://<>:8090/ In this case it is
  • This will take us to the exposed web service on a round robin basis and shares equal load between and

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