Today Citrix announced the Project Avalon Excalibur and Merlin Technology Previews to deliver Windows as a Cloud Service delivered across any network, to any device.

Project Avalon has a four tier architecture consisting of Self Service; Orchestration; Desktop and App Delivery and Cloud Infrastructure.

Other Citrix folks will give you the low down on the self service and orchestration tiers of Project Avalon; I am going to concentrate on how the Desktop and App Delivery tier integrates with the Cloud Infrastructure tier in order to enable Avalon to deliver Windows as a Cloud Service from any Cloud.

Cloud Infrastructure

Citrix CloudPlatform, powered by Apache CloudStack provides the latest and most advanced open source software platform to build highly scalable and reliable cloud computing environments. It can be used to power private on-premise clouds, and hosted clouds – either private or public.

Amazon Web Services is the originator and market leader in the public infrastructure as a service market. With data centres spread across the globe the Amazon cloud offers an almost infinitely elastic and flexible pay as you go infrastructure.

With the Merlin Technology Preview you will be able to leverage public and/or private cloud resources to provision VDI and server hosted desktops.

Desktop Optimized Clouds

Not every cloud is desktop ready! For the Merlin Technology Preview we require the cloud infrastructure to support all XenDesktop machine types including persistent (dedicated) and non-persistent (pooled) desktops, and provide support for personal vDisks.

In a multi-tenant environment we also require the cloud to provide shared networks for shared infrastructure, yet allow tenants flexibility in the level of isolation they have.

To better support Merlin we are also enhancing CloudStack to work on DaaS-optimized rack and blade chassis configurations with flexibility in allowing separation of VMs and their storage, whilst relying on CloudStack to optimise the placement of VMs to minimise ‘off rack’ traffic.

Desktop and App Delivery in the Cloud Era

Traditionally XenDesktop has been able to provision desktops in a range of hypervisor environments – Citrix XenServer, Microsoft SCVMM and VMware as well as on bare metal blades.

This works well in small scale environments, but at scale hypervisor pools need to be aggregated which gets complex.  In the Avalon architecture we achieve scale by delegating management of the hosting infrastructure to the Cloud Infrastructure tier, and enable XenDesktop to concentrate on its core function which is to provision and broker desktops and applications for end users.

The Merlin Technology Preview will add support for provisioning of VDI and hosted shared desktop workloads onto Citrix CloudPlatform and Amazon Web Services as illustrated by the following diagram.

This has been achieved by an internal re-architecture of the XenDesktop to make it aware of some cloud concepts that don’t exist in the hypervisor world and the addition of two new plugins to support the CloudStack and Amazon APIs.

The architecture revisions include an Open Cloud Plugin that implements a lot of the support necessary for Amazon like cloud APIs. This means that support for other Amazon like cloud APIs may be easily added to the system at a later date. Support for Microsoft Azure as a cloud infrastructure provider will be following soon. Which other cloud API would you like to see Avalon support?

The Merlin Technology Preview allows you to choose your Cloud Provider to give you the scale and the hosting characteristics you require – on-premise private clouds in your own data centre, hosted private clouds or public clouds from a Citrix CloudStack Service Provider and/or public cloud services from Amazon are all supported.

The process of creating a connection to your cloud infrastructure is just the same procedure you would use to connect to a local hypervisor – put in the URL of the cloud API and enter your credentials to connect to the cloud infrastructure. With a connection to cloud infrastructure you will need to specify which Availability Zone you wish to connect to rather than the cluster for a conventional multi-cluster hypervisor.

When provisioning workloads in the cloud the service designer just selects the Service Offering (or Instance Type in Amazon) required for the machine catalog, simplifying the process of consuming cloud infrastructure and creating a clear separation of roles within IT.

It is important to understand the flexibility of this architecture: the architecture of the integration between XenDesktop and the Cloud Infrastructure allows you to support different cloud infrastructure for different workload types.

Some desktops and workloads are best suited to execution in your private on-premise cloud; others can safely be run on public cloud infrastructure. The Avalon “any” cloud vision allows you to choose the cloud infrastructure best suited to your needs.