Build a Load Balancer network

Figure 1 shows a basic Load Balancer network with three locally attached workstations using the Dispatcher component's MAC forwarding method to load balance Web traffic between two Web servers. The configuration is similar when load balancing any other TCP or stateless UDP application traffic.

Figure 1. Load Balancer demonstration network
A graphic showing a Client, Internet cloud, a machine, and two locally-attached servers with addresses identified.
Note: This configuration can be completed using only two workstations with Dispatcher located on one of the web server workstations. This represents a collocated configuration.

Workflow

To build a Load Balancer network, perform these procedures in the following order:
  1. Review required computer systems and software.
  2. Configure the network.
  3. Configure the Dispatcher.
  4. Test the Load Balancer network.

Review required computer systems and software

The following computer systems and software components are needed:

  • Computer system to act as the Dispatcher. This system requires one actual IP address and one address to be load balanced.
  • Two computer systems to act as Web servers. Each Web server requires one IP address.

Configure the network

  1. Set up your workstations so that they are on the same LAN segment. Ensure that network traffic among the three machines does not have to pass through any routers or bridges.
  2. Configure the network adapters of the three workstations. For this example, assume you have the following network configuration:
    Workstation Name IP Address
    1 server1.company.com 9.67.67.101
    2 server2.company.com 9.67.67.102
    3 server3.company.com 9.67.67.103
    Netmask = 255.255.255.0
    Each of the workstations contains only one standard Ethernet network interface card.
  3. Ensure that server1.company.com can ping both server2.company.com and server3.company.com.
  4. Ensure that server2.company.com and server3.company.com can ping server1.company.com.
  5. Ensure that content is identical on the two Web servers (Server 2 and Server 3). This can be done by replicating data on both workstations, by using a shared file system such as NFS, AFS®, or DFS, or by any other means appropriate for your site.
  6. Ensure that Web servers on server2.company.com and server3.company.com are operational. Use a Web browser to request pages directly from http://server2.company.com and http://server3.company.com.
  7. Obtain another valid IP address for this LAN segment. This is the address you provide to clients who wish to access your site. For this example, the information is as follows: 
    Name= www.company.com
IP=9.67.67.104
  8. Configure the two Web server workstations to accept traffic for www.company.com.
    Add an alias for www.company.com to the loopback interface on server2.company.com and server3.company.com.
    • [AIX] For AIX®:

      ifconfig lo0 alias www.company.com netmask 255.255.255.255

    • [Solaris] For Solaris:

      ifconfig lo0:1 plumb www.company.com netmask 255.255.255.255

  9. Delete any extra route that might have been created as a result of aliasing the loopback interface.

    You have now completed all configuration steps that are required on the two Web server workstations.

Configure the Dispatcher

With Dispatcher, you can create a configuration by using the command line or the graphical user interface (GUI).

Note: The parameter values must be typed in English characters. The only exceptions are parameter values for host names and file names.

Configuring using the command line

If you are using the command line, follow these steps:
  1. Start the dsserver on Dispatcher:
    • [AIX] [HP-UX] [Linux] [Solaris] Run the following command as root user: dsserver
    • [Windows] dsserver runs as a service that starts automatically.
  2. Start the executor function of Dispatcher: 
    dscontrol executor start
  3. Add the cluster address to the Dispatcher configuration: 
    dscontrol cluster add www.company.com
  4. Add the http protocol port to the Dispatcher configuration: 
    dscontrol port add www.company.com:80
  5. Add each of the Web servers to the Dispatcher configuration: 
    dscontrol server add www.company.com:80:server2.company.com
    dscontrol server add www.company.com:80:server3.company.com
  6. Configure the workstation to accept traffic for the cluster address: 
    dscontrol executor configure www.company.com
  7. Start the manager function of Dispatcher: 
    dscontrol manager start

    Dispatcher now does load balancing based on server performance.

  8. Start the advisor function of Dispatcher: 
    dscontrol advisor start http 80

    Dispatcher now ensures that client requests are not sent to a failed Web server.

Your basic configuration with locally attached servers is now complete.

Configuring using the graphical user interface (GUI)

To start the GUI, follow these steps:
  1. Ensure that the dsserver process is running:
    • [AIX] [HP-UX] [Linux] [Solaris] Run the following command as root: 
      dsserver
    • [Windows] dsserver runs as a service that starts automatically.
  2. Next, do one of the following:
    • [AIX] [HP-UX] [Linux] [Solaris] Type lbadmin.
    • [Windows] Click Start > Programs > IBM® WebSphere® > Edge Components > IBM Load Balancer for IPv4 and IPv6 > Load Balancer for IPv4 and IPv6.

Test the Load Balancer network

  1. From a Web browser, go to location http://www.company.com to verify that a page appears.
  2. Reload the page in the Web browser.
  3. Issue the following command: dscontrol server report www.company.com:80:. Verify that the total connections column of the two servers adds up to 2.

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Timestamp icon Last updated: March 23, 2018 0:18
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