Configuring Site Selector

Before following the steps in this chapter, see Planning for Site Selector. This chapter explains how to create a basic configuration for the Site Selector component of Load Balancer.

Overview of configuration tasks

Note:
Before you begin the configuration steps in this table, ensure that your Site Selector machine and all server machines are connected to the network, have valid IP addresses, and are able to ping one another.
Table 13. Configuration tasks for the Site Selector component
Task Description Related information
Set up the Site Selector machine. Finding out about the requirements. Setting up the Site Selector machine
Set up machines to be load-balanced. Set up your load balancing configuration. Step 4. Define load balanced server machines

Methods of configuration

To create a basic configuration for the Site Selector component of Load Balancer, there are four basic methods of configuring the Site Selector component:

Command line

This is the most direct means of configuring Site Selector. The command parameter values must be entered in English characters. The only exceptions are host names (used, for example, in site name and server commands) and file names.

To start Site Selector from the command line:

  1. Issue the ssserver command from the command prompt. To stop the service, type: ssserver stop
    Note:
    For Windows systems, click Start > Settings (for Windows 2000) > Control Panel > Administrative Tools > Services. Right-click IBM® Site Selector and select Start. To stop the service, follow the same steps and select Stop.
  2. Next, issue Site Selector control commands you want in order to set up your configuration. The procedures in this manual assume use of the command line. The command is sscontrol. For more information about commands, see Command reference for Site Selector.

You can enter a minimized version of the sscontrol command parameters. You only need to enter the unique letters of the parameters. For example, to get help on the file save command, you can type sscontrol he f instead of sscontrol help file.

To start up the command line interface: issue sscontrol to receive an sscontrol command prompt.

To end the command line interface: issue exit or quit.

Note:
On Windows platform, the Dispatcher component's dsserver starts automatically. If you are using only Site Selector and not the Dispatcher component, you can stop dsserver from starting automatically as follows:
  1. From Windows Services, right-click IBM Dispatcher.
  2. Select Properties.
  3. In the Startup type field, select Manual.
  4. Click OK, and close the Services window.

Scripts

The commands for configuring Site Selector can be entered into a configuration script file and run together.

Note:
To quickly run the content of a script file (for example, myscript), use either of the following commands:

To save the current configuration into a script file (for example, savescript), run the following command:

sscontrol file save savescript

This command will save the configuration script file in the ...ibm/edge/lb/servers/configurations/ss directory.

GUI

For general instructions and an example of the GUI, see Figure 38.

To start the GUI, follow these steps

  1. Ensure ssserver is running. As root user or administrator, issue the following from a command prompt: ssserver
  2. Next, do one of the following:

In order to configure the Site Selector component from the GUI, you must first select Site Selector in the tree structure. After you connect to a host running ssserver, you can create site names containing servers, start the manager, and start advisors.

The GUI can be used to do anything that you would do with the sscontrol command. For example, to define a site name using the command line, you would enter sscontrol sitename add sitename command. To define a site name from the GUI, right-click Name Server, then in the pop-up menu, left-click Add Site Name. Enter the site name in the pop-up window, then click OK.

Pre-existing Site Selector configuration files can be loaded using the Load New Configuration (for completely replacing the current configuration) and Append to Current Configuration (for updating the current configuration) options presented in the Host pop-up menu. You should save your Site Selector configuration to a file periodically using the Save Configuration File As option also presented in the Host pop-up menu. The File menu located at the top of the GUI will allow you to save your current host connections to a file or restore connections in existing files across all the Load Balancer components.

To run a command from the GUI: highlight the Host node from the GUI tree and select Send command.... from the Host pop-up menu. In the command entry field, type the command that you want to run, for example: nameserver status. The results and history of the commands run in the current session appear in the window provided.

You can access Help by clicking the question mark icon in the upper right corner of the Load Balancer window.

For more information about using the GUI, see Appendix A. GUI: General instructions.

Configuration wizard

If you are using the configuration wizard, follow these steps:

  1. Start the ssserver on Site Selector:

  2. Start the wizard function of Site Selector, sswizard.

    You can launch this wizard from the command prompt by issuing the sswizard. Or, select the Configuration Wizard from the Site Selector component menu as presented in the GUI.

The Site Selector wizard guides you step-by-step through the process of creating a basic configuration for the Site Selector component. It asks you questions about your network and guides you as you setup a site name that enables Site Selector to load balance traffic between a group of servers.

Setting up the Site Selector machine

Before setting up the Site Selector machine, you must be the root user (for AIX, HP-UX, Linux, or Solaris systems) or the Administrator (for Windows systems).

You will need an unresolvable fully qualified hostname to use as a site name for a group of servers that you set up. The site name is the name that the clients use to access your site (such as www.yourcompany.com). Site Selector will load-balance traffic for this site name among the group of servers using DNS.

Step 1. Start the server function

To start the Site Selector server function, type ssserver on the command line.

Note:
A default configuration file (default.cfg) gets automatically loaded when starting ssserver. If you decide to save the configuration in default.cfg, then everything saved in this file is automatically loaded next time ssserver gets started.

Step 2. Start the Name Server

To start the Name Server, enter the sscontrol nameserver start command.

Optionally, start the Name Server using the bindaddress keyword to bind only to the specified address.

Step 3. Define a site name and set site name options

Site Selector will balance the requests sent for the site name to the corresponding servers configured to it.

The site name is an unresolvable host name that the client will request. The site name must be a fully qualified domain name (for example, www.dnsdownload.com). When a client requests this site name, one of the server IP addresses associated with the site name is returned.

To define a site name, issue the following command:

sscontrol sitename add sitename

To set site name options, issue the following command:

sscontrol sitename set sitename option value

For more information, see Command reference for Site Selector.

Step 4. Define load balanced server machines

The server machines are the machines running the applications that you want load balanced. The server is the symbolic name or dotted decimal address of the server machine. To define a server on the site name from step 3, issue the following command:

sscontrol server add sitename:server

You must define more than one server under a site name in order to perform load balancing.

Step 5. Start the manager function (optional)

The manager function enhances load balancing. Prior to starting the manager function, ensure that the metric server is installed in all the load-balanced machines.

To start the manager, issue the following command:

sscontrol manager start

Step 6. Start the advisor function (optional)

The advisors give the manager more information about the ability of the load balanced server machines to respond to requests. An advisor is specific to a protocol. The Load Balancer supplies many advisors. For example, to start the HTTP advisor for a specific site name, issue the following command:

sscontrol advisor start http sitename:port

Step 7. Define system metric (optional)

See Metric Server for information on using system metrics and Metric Server.

Step 8. Set site name proportions as required

If you start advisors, you may modify the proportion of importance given to advisor (port) information being included in the load balancing decisions. To set the site name proportions, issue the sscontrol sitename set sitename proportions command. For more information, see Proportion of importance given to status information.

Setting up server machines for load balancing

Use Metric Server with the Site Selector component. Refer to Metric Server for information on setting up Metric Server on all server machines that Site Selector is load balancing.