Life in a virtual world
By Peter Worlock
Peter Worlock finds out what virtualisation can do for your businesses.
HardCopy Issue: 49 | Found In: Virtualisation | Published: 14/09/2010 | Last Revision: 14/10/2010
Like the teen obsession with vampires, IT’s appetite for virtualisation is apparently limitless. A recent report from researcher IDC suggested that by the end of last year, 20 per cent of new servers shipped in western Europe were virtualised. The same report also revealed that commercial virtualisation software was running on more than 70 per cent of new server hardware.
But while server virtualisation is the Big Daddy of the market, the industry has moved rapidly to extend the benefits of virtualisation to other areas, including storage, network, desktop and application virtualisation. When you review the promised payoffs, it isn’t hard to see the appeal of all things virtual.
Virtual appeal
The initial impetus towards virtualisation arose from the widespread under-use of server hardware. With the average standalone server reaching just 30 per cent utilisation, IT managers spotted the opportunity to optimise workloads, improve efficiency and save money at the same time. Virtualisation allows you to run 10 or 20 or even more virtual servers on just a handful of machines with commensurate savings in power consumption, cooling requirements, maintenance and so forth.
But the benefits stretch far beyond the financial. The ease with which you can create ad-hoc virtual machines (VMs), and move them from server to server as required, makes for greater reliability, greater application availability and easier disaster recovery.
Disaster recovery is a particular benefit of virtualisation. The virtualised environment lets you take snapshots of servers, desktops and other resources and store them remotely. In the event of disaster, those images can be restored from a backup centre with little or no loss of service.
Similar benefits accrue from desktop virtualisation, allowing you to consolidate resources and simplify management and maintenance. Desktop virtualisation allows you to store an entire desktop environment on a central server from where it can be accessed by remote client. This gives multiple users access to a standard set of applications and resources, while IT enjoys greatly simplified installation and maintenance. Costs can be lower because the client machines can be much simpler and less powerful, while security is enhanced through central file storage, and by denying users the ability to install unapproved software.
At the next level down is the ability to virtualise the applications themselves. By encapsulating the application software, together with any necessary ancillary code such as device drivers and DLLs, you can create applications that can be run in isolation from the rest of the IT environment. Advantages include the ability to run legacy software on new and potentially incompatible hardware and operating systems, avoiding conflicts with other software, and providing users with a standard, tightly-controlled software suite that cannot be modified. Users also have the ability to create a software toolkit that can be encapsulated on a USB key or other storage device and then run from any computer – including public terminals – without the need to modify the host system in any way.
Virtual Solutions
The core component of any server virtualisation environment is the hypervisor, the essential software that sits between the underlying physical hardware and the operating system and applications. The leading players in the market are VMware with its ESX and ESXi, and Microsoft with Hyper-V Server, although rival systems are available from Citrix, Virtual Iron and Sun.
Virtualisation made simple: This image is just a part of a Microsoft poster illustrating the Hyper-V architecture.
However, the hypervisor itself is just one part of the picture as it must be accompanied by a suite of tools for management, monitoring, backup and recovery. The hypervisor vendors offer their own solutions but there is a large and growing market of third-party software providing both all-in-one suites and dedicated single-task solutions. They include Quest, SolarWinds, Vizioncore and Veeam.
The lead players have also turned their eyes to desktop virtualisation. Microsoft, VMware and Citrix offers solutions in this area, alongside third-party vendors such as 2X Software and Quest Software.
With regards to application virtualisation, the leading players are joined by 2X Software, Novell and Symantec.
In the open source market, virtualisation is a small but growing sector, with market research company Gartner predicting it could take as much as 12 per cent of the overall market within the next two years. Some leading vendors, including Citrix, offer open source solutions, and other Linux-based systems are available from RedHat, Zenoss and VirtualBox.
Traps and pitfalls
So virtualisation offers you the ability to optimise the use of hardware you currently own, reduce the need for hardware investment going forward, simplify IT management and maintenance, make disaster recovery much easier, and save a bunch of money in the process. As our American friends say, what’s not to like?
The short answer is nothing, provided your virtualisation project delivers. However there are a many potential problems for the unwary. Foremost among them is an over-ambitious estimate of server consolidation.
While many suppliers boast the ability to host as many as 100 VMs on a single physical server, real world projects rarely get close to that figure. For example, a 2009 study of virtualisation projects in organisations with more than 500 end users discovered that consolidation rates of 6:1 were typical for core applications such as CRM, email and databases.
Not all applications are suitable for virtualisation, although often the problem lies with a particular resource becoming saturated – something which can be overcome by fine tuning if you can find someone with the necessary expertise. Consider also applications that require USB or other hardware keys for copy-protection, as these are unlikely to work in a virtual environment. Similar considerations apply to any software that demands sole access to particular hardware.
An additional issue is that of licensing, both for server software and for the applications themselves. Some vendors opt for a per-CPU licence, which can be confusing and limiting in a virtual environment. Others offer more flexible terms under which disaster recovery images don’t count. But in any case, virtualisation requires that you have a management and monitoring system to account for available and issued licences.
Early virtualisation solutions put multiple VMs on a single server, which could lead to bottlenecks. Directing the necessary traffic through a single server could overwhelm its network connections, for example. These days you can spread the load across multiple servers, and indeed solutions such as VMware DRS does this dynamically to ensure each VM gets the headroom it needs.
Another problem is virtual server sprawl. Because VMs can be created quickly and easily, it’s easy to lose track of them. An ad-hoc VM created to solve a particular issue on Monday may be out of use by Friday – but never shut down, so continuing to consume resources.
Although some staff view VMs as effectively free, there are usually costs associated with software licensing – at least for security and anti-virus apps, if not for the server software itself. VMs also incur costs for system maintenance and energy consumption.
Perhaps the greatest problem with VM sprawl is increased complexity for management and maintenance – precisely the issues that virtualisation is meant to benefit. Working with VMs requires new disciplines, and these take time to learn.
Virtual success
Management is one of the keys to a successful virtualisation programme. While historically the major vendors offered tools for management, monitoring and administration, the end result was increasing complexity for IT centre staff. One survey suggests that typical virtualisation deployments resulted in multiple tools, from as many as 11 different vendors, that needed to be installed, learned, configured and integrated into existing operations. In many cases these overlap or duplicate existing tools and strategies.
A recent development has been the introduction of overarching management and monitoring tools from third-party vendors offering all-in-one solutions. Veeam’s eponymous Management Suite, for example, promises total control of VMware systems, handling performance monitoring, file management, backup and recovery, and reporting. The company also offers tools that integrate VMware management with existing management tools from Microsoft and HP.
In a similar vein, Vizioncore provides a suite for monitoring, management, replication and backup for VMware. New features in the company’s vFoglight software also support virtualised Microsoft Active Directory and Exchange.
Under new management: Veeam’s management suite for VMware provides an all-in-one solution to the vital issue of virtualisation management.
Naturally the major virtualisation vendors have also developed comprehensive management and administration toolsets. VMware, for example, offers vCenter, an integrated suite of a dozen modules providing planning, capacity management, recovery and performance monitoring. Microsoft offers similar tools under its System Center banner, including Virtual Machine Manager, Operations Manager, Configuration Manager and Service Manager.
Controlling VM sprawl is a particular management challenge. It is essential that you have processes in place that control who has the ability to create a VM, and ensure that they are monitored and tracked. This includes VMs that may have been offline for weeks or months.
Network management also becomes much more important in the virtualised environment where the consolidation of multiple systems on to few physical servers means more network traffic through fewer network interface cards. Traditional network monitoring tools may lack the ability to deal with virtualised server traffic, so new systems monitoring tools may be required.
Virtual appliances
One of the quickest and easiest ways to take advantage of virtualisation is through the use of ‘virtual appliances’. Applying virtualisation techniques to a single application results in a solution that is quick to deploy, with minimal installation and no impact on the rest of your IT infrastructure.
Virtual appliances are built on the concept of ‘just enough operating system’ or JeOS (pronounced ‘juice’). The basics of the JeOS could be Linux, Windows or something else, but the appliance uses only the components of the OS necessary to run the application. The application itself, the JeOS, together with drivers and any other necessary components, are encapsulated in a one-shot installer that eliminates the complexity of integrating these parts with the whole of your IT environment.
TPlug-and-play virtualisation: VMware’s catalogue of virtual appliances.
The ideal deployment for an appliance is on a virtual machine, but you can also install and run them on a single computer, which then effectively becomes the server for the application.
The advantages are many, beginning with the ability to deploy the app very quickly. Installation, as noted, is greatly simplified with little or no testing since the vendor has already ensured compatibility and interoperability between the encapsulated components. Because the application runs in a sandboxed environment, there should be no conflicts with other software, reducing maintenance and support requirements.
VMware currently leads the field for VAs offering around 1,000, including dozens under its ‘VMware Ready’ banner. They include email systems such as Symantec’s Brightmail gateway, security solutions like Trend Micro’s LeakProof and Astaro’s Security Gateway, and multiple management and monitoring solutions.
In the Linux market, virtual appliances have become popular for deploying complex Web services and content management systems, including Ruby on Rails, Joomla! and Drupal. Adobe has also joined the movement with the introduction of a VA version of its LiveCycle software. This encapsulates a SUSE Linux operating system, JDK, J2EE application server and MySQL database management system.
Although it is possible to treat many VAs as production-ready tools, most (including Adobe’s LiveCycle) are better thought of as an easy means of testing solutions. To be most effective, you need to create your own virtual appliances that are configured to work perfectly within your own IT environment.
Finally, you should be aware that although virtualisation generally provides for improved reliability, availability and disaster recovery, in the worst-case scenario it can make a failure disastrously worse. In a traditional data centre, where individual applications run on individual physical servers, the failure of one server is rarely critical. In a virtualised environment, losing just one physical server can affect multiple applications, particularly if the system is not properly balanced.
Virtual futures
Virtualisation was initially a software initiative. Hypervisor software sits between the operating system and the underlying hardware, translating commands and results between the two. But in response to the demand for virtualisation, leading CPU manufacturers like Intel and AMD have introduced hardware changes that reduce or even eliminate the need for that translation, making virtualisation much more efficient.Similar developments have occurred in memory and storage technologies, and we can expect to see further improvements that will increase performance in virtualised environments. In fact, with today’s multicore processors, there is often little or no performance penalty in running virtualised applications.
We are seeing similar developments in the operating system where virtualisation support is becoming increasingly important. For example, the forthcoming release of Microsoft Windows Server 2008 R2 SP1 (currently in beta) features two major enhancements for virtualisation. The first, Dynamic Memory, should make memory allocation in the virtual environment much more flexible, allowing higher consolidation ratios and improved performance (although this has been a feature of VMware ESX for several years). The second, RemoteFX, provides a suite of Remote Desktop Services that should allow the delivery of high-performance graphics, animation and video to client machines across a network. Microsoft has also reached an agreement with Citrix that will allow it to use RemoteFX within the latter’s XenDesktop virtualisation solution.
Built on these enhancements, the rise of virtual desktops and virtual applications means that the future of IT – at least in the corporate environment – may be a future of virtualisation everywhere: virtual apps running on virtual operating systems running on virtual machines connected to physical servers, either wired or wirelessly, over high-speed networks.
But for small-to-medium-size businesses that haven’t yet started on that long road, the good news is that you can start easily and see very quick returns. If you have two or more servers, virtualisation makes sense. With a recent desktop system that has a multicore CPU and plenty of memory, you can even try several virtualisation packages for free and without the need to buy new server hardware. And because your virtualisation software will allow you to take VM snapshots, if you do hit problems you can easily roll-back to a stable state.