Citrix XenApp in the Cloud
With the current products and technology that Citrix can offer it is possible to create a multi customer private or public cloud for Citrix XenApp.
XenServer can be used as the virtualization platform for hosting all the components. XenServer will deliver the best performance when virtualizing Citrix XenApp workloads. With recent hardware based on Intel Nehalem CPU’s you can virtualize up to 8 Citrix XenApp x86/x64 servers that can deliver 500+ sessions per physical server.
Citrix Provisioning server can be used to create a small number of single images that will be used for all customers. The customer will have a fixed number of virtual XenApp servers available in a separated network segment/VLAN. The single Citrix Provisioning server images will receive all Citrix and Microsoft updates making it easy to update the Citrix XenApp servers for all customers.
Most likely there will be three master Citrix provisioning images for Citrix XenApp in the cloud:
– XenApp 5 FP3 on Windows Server 2003 x86
– XenApp 5 FP3 on Windows Server 2008 x86
– XenApp 6 on Windows server 2008 R2 x64
The XenApp 6 image can not be combined with XenApp 5 images in the same farm, t is not possible to have a mixed farm with Citrx XenApp 5 & 6
The applications that the customers want to use with their cloud XenApp servers will be offered virtualized with Citrix streaming, Microsoft App-V, VMWare ThinApp or any other 3rd party tooling. This is required to separate the applications from the re-usable master images that will be used for all customers
Unfortunately application that cannot be virtualized cannot be added to the Citrix XenApp cloud, these applications would require a dedicated XenApp servers.
For the customers it will not be important to know on what Citrix XenServer their Citrix XenApp server(s) are running. Citrix XenApp servers from multiple customers can be combined with the Citrix XenApp servers from other customers. Separation on the network layer will make sure that a customer can only access their own Citrix XenApp servers.
On the front end Citrix Netscaler VPX appliances running on Citrix XenServer can be used to control access. Security can be enhanced with a SMS/Texting password system that can SMS/Text a token to the end user’s mobile phone. This will allow secure access without the need to manage physical tokens.
The Citrix receiver will offer client software updates and a self-service application store (dazzle will be integrated in the Citrix receiver) allowing the customers to choose themselves what applications they want to have available in their Web interface (based on the virtual application they have added to their Citrix XenApp cloud).
Optionally storage for saving company documents can be added to the service.
Citrix Branch Repeater VPX appliances can also be added to the Citrix XenApp cloud design.
For redundancy the design will require a provisioning server farm, multiple web interfaces, multiple Netscaler VPX appliances and redundant storage.
Personally I would like to add the RES Workspace Manager (Powerfuse) to the design. The RES Workspace Manager can be used to easily secure the environment/desktop and keep user profiles small and fast with zero profile technology.
Most customers will probably require basic applications such as Adobe acrobat Reader and the default Internet Explorer add-ons to display the majority of the internet pages. The master images should contain this basic set of applications and add-ons + antivirus software.
For Microsoft Office the cloud supplier can offer default packages with virtualized Micrsoft Office applications that can be combined with the customers official license for their Citrix XenApp cloud
The cloud provider can charge the customer for the number of Citrix XenApp servers they need, for the number of virtual-applications the customer adds to their cloud or for the number of users that will connect.
Basic overview of the Citrix XenApp in the Cloud infrastructure:
Migrating Citrix XenApp enviroments to Citrix XenApp clouds offered by cloud providers or System Integrators can have many advantages.