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Basic Principles of designing Citrix XenApp Environments Part 5

This article is part five of an article series about Citrix XenApp design decisions. The starting article can be found here.

Client Connections Architecture & Design


Often this part is not mentioned in the design and during the implementation many questions are arising on this topic. Be sure to discuss this part with the customer/organization thoroughly how the users will connect to the Citrix Farm.

Discuss the following topics:

  • Way of Access

Of course this situation is different in every organization and dependent of the client types. In scenarios where Published Applications are used really differs in comparison with Published Desktop. With Published Applications embedding the applications within the fat client system (start menu, desktop shortcuts) has more importance than a single link to the Published Desktop. Think about the decision between the Program Neighborhood Agent/ Citrix XenApp Client, Web Interface or another method. Also if the farm is reachable from external locations there should be determined how this should be accomplished and the requirements for such access with components in the DMZ. Think of the Citrix Secure Gateway (software), the Citrix Access Gateway or Citrix Advanced Access Control (called CAG advanced).

  • Type of ICA/XenApp clients

Beside the decision how the applications will be displayed to the user also the type of ICA/XenApp Client need to be described in the design. Will the organization install the full ICA client (nowadays called Citrix XenApp Plugin for Hosted Applications), the XenApp Client (PNA), (when using the Web Interface) the web client or the java client. After deciding the type of client also describes in the design how the client will be distributed. For example the PNA and XenApp Plug do not provide an automatic installation methodology by Citrix (also requires administrator rights on the device), so this should be deployed using a distribution tool. When using the Citrix Web Interface the web client or java client can be installed automatically on the client without administrator rights.

In most current situations you see that internal the full client or the PNA client will be installed using a distribution methodology also when the Web Interface is used as the method to display the applications to the end-user. For external access the web client is most used, because of better performance and display of the session in comparison with the java client. Current implementations are mainly based on the usage of the PNA client or the Web Interface for displaying the applications to the end-users. For external access the Citrix Access Gateway Advanced (Citrix Advanced Access Control) is the most used options, although Citrix still supports the Citrix Secure Gateway software product.

It also a good thing when to describe a small paragraph about the client it selves especially when using Thin Client. In big projects this will be a separate design document.

Monitoring Citrix Architecture & Design

Also Monitoring is one of the subjects, that is often not mentioned in designs. First need to be determined what need to be monitored and how alerts need to be send and what kind of reporting is needed. Personally I find monitoring one of the most important for troubleshooting and determine the growth of the infrastructure. With the old Resource Manager and the acquisition of EdgeSight Citrix has also products and/or components available for monitoring.

Discuss the following points and describe the decision points in the design:

  • Available Monitor Software

There are companies which already have a monitor software product in their infrastructure. Check if this version can be on the Citrix Servers and can monitor all the necessary information. Citrix also have connectors in (the old) Resource Manager which can port the logged information to the bigger third-party monitor products.

  • Need of alerting and reporting

Discuss the real needs for alerting and reporting. Setting up a monitor environment is just the first step. What should be done if the monitor software notices that a value is higher than normal? Which persons should be notified, when those persons should be notified and how they should be notified? Also check the needs for reports about the infrastructure. It is unnecessary to create a nice report about CPU and Memory utilization, while the manager actually (only) wants to know if the infrastructure was up and running from an end-user point of view.

  • Movement of Citrix Resource Manager to EdgeSight

Previous version of Citrix Presentation Server (Enterprise or higher) have the Resource Manage feature embedded. Although this was a useable feature, Citrix has moved this functionality to EdgeSight in XenApp 5. Consider this when writing a design for Citrix Presentation Server 4.5 that when upgrading is done this should be redesigned.

  • Resource Manager Roles and Counters

If using Citrix presentation Server 4.5 or earlier and you would like to deploy Resource Manager remember that 50 counters in the Resource Manager per server is the advised maximum. Also describe the placement of the Resource Manager Roles.  Read more about the resource manager in this article, written earlier on VanBragt.Net.

I strongly recommend creating a baseline with a normal user load on the servers. This baseline can be used to compare the load on the servers during troubleshooting issues or to extrapolate additional needed capacity. When there are no special products available just use the default Windows Performance Monitor.

Concerning monitoring determine in an early stage the real needs for alerting and reporting and mention the efforts (and costs) to create such reports. I normally use the monitoring software if this is already available or (when no product is available) the Resource Manager/EdgeSight functionality.

To be continued

This article will continue in a next article describing more Citrix XenApp design decisions.