Load Balancer using mod_proxy_balancer on Ubuntu

I am assuming you know where site-enabled and other folders are
enable modules and configuration following below

/etc/init.d/apache2 stop
sudo a2ensite mynewsite
sudo /etc/init.d/apache2 restart
a2dissite utility to disable sites

Go to /etc/apache2 

0.
sudo a2enmod proxy
sudo a2enmod proxy_http
sudo a2enmod proxy_ajp

1. Modify the config file from sites-enabled folder >nano 000-default and add the below configuration change the documentRoot to the location where you have unzipped the Tomcat I unzipped under /home/localadmin

NameVirtualHost *:80
<VirtualHost *:80>
 ServerName ubuntu
 DocumentRoot /home/localadmin/
 ProxyRequests Off

 <Proxy *>
 Order deny,allow
 Allow from all
 </Proxy>

 ProxyPass /balancer-manager !
 ProxyPass / balancer://mycluster/ stickysession=JSESSIONID nofailover=On
 ProxyPassReverse / http://localhost:8081/   ----three tomcat instance will be running on different ports change server.xml of tomcat to make that work also change the below ajp port in server.xml
 ProxyPassReverse / http://localhost:8082/
 ProxyPassReverse / http://localhost:8083/

 <Proxy balancer://mycluster>
# BalancerMember http://localhost:8081  route=a1
# BalancerMember http://localhost:8082  route=a
  BalancerMember ajp://localhost:8109 route=a1
  BalancerMember ajp://localhost:8209 route=a2
  BalancerMember ajp://localhost:8309 route=a3
  ProxySet lbmethod=byrequests
 </Proxy>

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

</VirtualHost>



2. Enable proxy in proxy.conf in mods-enabled folder

<IfModule mod_proxy.c>
        #turning ProxyRequests on and allowing proxying from all may allow
        #spammers to use your proxy to send email.

        ProxyRequests Off

        <Proxy *>
                AddDefaultCharset off
                Order deny,allow
                Deny from none
                #Allow from .example.com
        </Proxy>

        # Enable/disable the handling of HTTP/1.1 "Via:" headers.
        # ("Full" adds the server version; "Block" removes all outgoing Via: he$
        # Set to one of: Off | On | Full | Block

        ProxyVia On
</IfModule>

From terminal find your >servername this will return your server name
Tip: Restart apache and try the link below
using http://yourservername/balancer-manager