by Matthias Pfützner
Published March 2013 (reprinted from eStep blog
Part 8 - Oracle Enterprise Manager Ops Center as a Management Tool for Virtualization
Part 7 - The Role of Oracle Virtual Desktop Infrastructure in a Virtualization Strategy
Part 6 - Oracle VM VirtualBox - Personal Desktop Virtualization
Part 5 - Network Virtualization and Network Resource Management
Part 4 - Resource Management as an Enabling Technology for Virtualization
Part 3 - The Role of Oracle Solaris Zones and Linux Containers in a Virtualization Strategy
Part 2 - The Role of Oracle VM Server for x86 in a Virtualization Strategy
Part 1 - The Role of Oracle VM Server for SPARC in a Virtualization Strategy
Now that we've finished the overview of individual virtualization technologies from Oracle using hypervisors and operating system features, it's time to look at the desktop virtualization product known as Oracle Virtual Desktop Infrastructure.
Note: For an introduction to the different levels and types of virtualization technology, see the first article in this series.
Before diving deeper, let's define what a virtual desktop infrastructure (VDI) is. Wikipedia once provided the following definition (which we deem better than its current definition, which is Microsoft Windows–centric):
"Desktop virtualization involves encapsulating and delivering either access to an entire information system environment or the environment itself to a remote client device. The client device may use an entirely different hardware architecture from that used by the projected desktop environment, and may also be based upon an entirely different operating system. The desktop virtualization model allows the use of virtual machines to let multiple network subscribers maintain individualized desktops on a single, centrally located computer or server. The central machine may operate at a residence, business, or data center. Users may be geographically scattered, but all must be connected to the central machine by a local area network, a wide area network, or the public Internet."
Or, here's a short definition:
"Virtual desktop infrastructure (VDI) is the practice of hosting a desktop operating system within a virtual machine (VM) running on a hosted, centralized or remote server."
To help our understanding, let's put this concept into a picture:
Figure 1. Visual Representation of a VDI
In order to achieve such an environment, multiple pieces are needed:
Oracle has all the pieces, and some of them have already been described in previous articles in this series. But users want choice, so it is also possible to use non-Oracle products with Oracle Virtual Desktop Infrastructure.
Before we describe these parts in more detail, Figure 2 shows an overview of Oracle Virtual Desktop Infrastructure taken from the product documentation.
Figure 2. Overview of Oracle Virtual Desktop Infrastructure
Lets start with the end-user devices:
Some fifteen years ago, Sun created the Sun Ray, which now is in its third generation (Oracle's Sun Ray 3 Series Clients) and is also available as a software-only product (Oracle Virtual Desktop Client) that can be run on the iPad, Mac OS, Windows, and Linux. With Oracle Virtual Desktop Client, a broad variety of end-user devices are possible, ranging from "zero admin devices" (such as the physical Sun Ray itself), to classical desktop systems running software to access the VDI desktop, to mobile devices such as the iPad, allowing instant access to a user's desktop anywhere on this planet.
Moving from the end-user devices closer to the data center, let's look at the network part of the infrastructure:
As mentioned above, desktop virtualization needs an encoding tool on the server side; the Sun Ray Software is the corresponding counterpart for the client devices. The protocol used is Appliance Link Protocol (ALP), which is a Sun Ray–specific protocol. ALP is particularly well suited for wide area networks, so massively centralized infrastructures can be built in large global enterprises.
Moving again closer to the "desktop run in a data center," let's look at the virtualization components:
Somehow the desktop operating systems need to be virtualized. This can be done via a variety of so-called desktop providers/connectors, one of which is Oracle VM VirtualBox, which was described in the previous article in this series. Providers/connectors for Citrix XenDesktop, VMware vSphere, VMware View, Microsoft Hyper-V Server 2008, or Microsoft Remote Desktop Services 2008 also exist.
Moving away from the underlying enabling technologies, let's look at the management component:
Because VDI setups are accessed by thousands of users and host thousands of individual desktops, access management needs to be done for all the possible mappings between users and their sessions/desktops. This is handled by the desktop broker, which is an integral part of Oracle Virtual Desktop Infrastructure that allows connection to an enterprise database containing access information—for example Active Directory or LDAP—and stores its internal information in a MySQL database. This allows for easy management and migration of already existing corporate desktop infrastructures into an Oracle Virtual Desktop Infrastructure environment.
Then there is the storage space:
Here, the setup and provisioning of new user desktops needs to be managed because all the desktops are stored in the desktop operating system disk images. This layer also uses other Oracle technologies to speed up the process, for example, cloning of existing desktop "golden images" via storage subsystem methods. The cheapest VDI solution, then, would be a single x86 server with a bunch of internal disks. But setups consisting of many x86 servers with external storage, such Oracle's Sun ZFS Storage Appliances, are also possible.
Oracle Virtual Desktop Infrastructure is a complete VDI solution that makes intelligent reuse of already existing technologies to provide virtualized desktops to end users.
Matthias Pfützner worked at Sun Microsystems and Oracle from 1998 until 2012. During his 14 years in the Professional Services and Presales groups at Sun and Oracle, he supported technologies such as clustering, provisioning, systems management, virtualization, and cloud computing for customers such as Deutsche Bank, Deutsche Telekom, Vodafone, and Daimler Chrysler. As one of approximately a hundred worldwide Principal Field Technologists at Sun and Oracle, he helped define and shape these technologies, influenced IT businesses around the world, and gave many presentations at conferences and customer meetings.
Matthias would like to thank Uwe Strahlendorf and Detlef Drewanz for the invaluable feedback they provided for this article.
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