Product Documentation

Use Case 13: Configuring XenApp for Load Balancing

Jun 08, 2015

For efficient delivery of applications, you can integrate the NetScaler appliance with Citrix XenApp and use the NetScaler load balancing feature to distribute the load across the XenApp server farms. The following figure is a topology diagram of such a setup.

Figure 1. Load Balancing of XenApp
Load Balancing of XenApp

The Web Interface servers provide secure access to XenApp application resources through the user's Web browser. The Web Interface client presents to the users all the resources, such as applications, content, and desktops that are made available in the XenApp server farms. Users can access the published resources through a standard Web browser or through the Citrix online plug-in.

The Web browser on the user's device sends information to the Web server, which communicates with the servers on the server farm to provide the user with access to the resources.

The Web Interface and the XML Broker are complementary services. The Web Interface provides users with access to applications, and the XML Broker evaluates the user's permissions to determine which applications appear in the Web Interface.

The XML service is installed on all the servers in the server farm. The XML service specified in the Web Interface functions as an XML broker. On the basis of the user credentials passed by the Web Interface server, the XML Broker server sends a list of applications accessible to the user.

In large enterprises where multiple Web Interface servers and XML Broker servers are deployed, Citrix recommends load balancing these servers by using NetScaler. Configure one virtual server to load balance all of the Web Interface servers and another for all of the XML Broker servers. The load balancing method and other features can be configured on the virtual server as required.

Note: Although you can use the HTTP protocol, Citrix recommends that you use SSL for communication between the client and the NetScaler. You can use the HTTP protocol for communication between the NetScaler and the WI servers even though you use the SSL protocol for communication with the client.

The configuration utility provides a wizard for setting up basic load balancing for XenApp.

Through this wizard, you can configure Web Interface servers and a virtual server for them, and XML Broker servers and a virtual server for them. You can also specify the site through which the status of Web Interface servers can be monitored and the software application used to monitor the status of the XML Broker servers.

When you complete the wizard, a basic load balancing setup is configured on the NetScaler. The specified virtual servers are created and bound to the services specified as Web Interface services and XML Broker services. Each virtual server is configured with the default load balancing method, and the default features are enabled. A monitor is created and bound to each virtual server.

The wizard creates a basic setup with default values for options such as the load balancing method, policies, persistence, and advanced settings. You can change any of the values if necessary.

To configure load balancing for XenApp by using the configuration utility

Click XenApp and XenDesktop, and follow the instructions in the wizard.