by Theresa Miller
Interested in taking advantage of some of the new technical advantages of XenDesktop 7.6? Not sure what these advantages might be, then here is a link to an article that covers that topic. After understanding the benefits, is your team ready to start thinking about what it means to design your XenDesktop 7.6 environment? Here are some of the architectural considerations that should be thought about before moving into an implementation.
When architecting XenDesktop 7.6 there are several major components that your environment will require. The Virtual Desktop Agent, Delivery Controllers and your SQL Database. Your organization will also need to implement a web-based front-end and application servers to get your environment up and running. This article will cover each of these components and the things that your team should be considering when deciding how to design you XenDesktop environment.
The VDA is a lightweight agent that must be installed and present on any virtual machines that users connect to. This includes Citrix servers and any desktop workstations that users may want to connect to through Citrix Receiver. The purpose of this agent is to allow the machine to register with the Delivery Controllers which we will touch on more in the next section of the write-up. The VDA Agent also manages the HDX connection between the machines and the user devices. HDX enhancements allow graphically intensive applications to function within Citrix sessions.
VDA can be installed on the following desktop and server operating systems.
- Workstation – Win 7SP1, 8 and 8.1
- Server – Windows 2008 R2 SP1, 2012 and 2012 R2
The delivery controllers essentially replace the original XML broker and Zone Data Collectors that came with XenApp 6.5 and older. The delivery controllers typically live in your data center and distribute applications and desktops, authenticates user access, and broker’s connections between users and target resources. There should be at least two of these in your environment and depending on the size of the organization it may be important to have more. Here is an article that can provide some additional insight into the decision behind how many Delivery Controllers you deployment needs.
Also here is a list of the primary Delivery Controller Services.
- Active Directory Identity Service
- Machine Creation Service
- Citrix Environment Test Service
- Host Service
- Monitoring Service
- Broker Service
- Configuration Service
- Configuration Logging Service
- Delegated Admin Service
Be sure that these services are running at all times for the best uptime of your XenDesktop 7.6 environment.
Your XenDesktop environment will require a database that stores your Citrix site configuration, configuration logging and monitoring data. Your environment will require persistent database availability so in order to ensure the best uptime for your environment it may be worthwhile to implement SQL mirroring or clustering of this database. Also if segregation of data in the database is of interest the Citrix Site, Configuration Logging and monitoring scheme can be saved to separate databases. Regardless of the design implemented these databases should be backed up routinely.
Web Interface or StoreFront?
A lot of organizations that choose Citrix have previously deployed Web Interface for web-based access to their Citrix farms. Citrix has gone back and forth many times in the last several years as it relates to their support stance of this product, but has now committed to StoreFront as a replacement for Web Interface. Web Interface is end-of life on August 24, 2014, but they have an optional extended support option that will run through January 14, of 2020. Depending on your support contract it may be time to make the move. Also more information about support can be found here. http://www.citrix.com/support/product-lifecycle/milestones/xendesktop.html
That being said here are some of the benefits of StoreFront and in some ways will resemble what we have previously used in Web Interface. Store Front presents the user their customized list of applications within either a web browser or through Citrix Receiver. It can be secured using SSL or 2 factor authentication. Any new integrations that typically would have been developed for Web Interface are now only being implemented in StoreFront. If your organization will plan to implement XenMobile for securing corporate data on mobile devices then Store Front is required. So, Citrix is making it quite evident that organizations should be considering this as a replacement sooner rather than later.
For application servers the recommendation is simple. Deploy n+1 for your applications which means always have at least one more server that you will need. Always make sure if one of the servers goes down that there is at least one extra server available that has the resources to take on that extra capacity. If it’s a large scale application then it might make sense to have multiple extra servers for redundancy and maintenance purposes. Another way to think about this is to size to scale and add 25% more capacity than you expect to need.
Citrix has a nice sizing tool that can help with determining what the design of your Citrix environment might be. It is called Project Accelerator and can help your organization get started with designing XenDesktop 7.x & 5.6, XenApp 6.5, XenApp 7.x. Here is a link http://project.citrix.com/
Thoughtful planning of these various aspects will get your team started with a successful XenDesktop deployment.