Using free PC virtualisation tools

Virtualisation is rapidly becoming a commodity technology, leaving vendors to focus on the development of management and other add-ons. As a result, a lot of the leading PC and server virtualisation products are now free ­ but is there a catch?

In this feature we look at what the virtualisation freebies have to offer the small business and whether you will need buy any extras to maximise the benefits.

The virtual landscape
PC virtualisation products are primarily aimed at developers, system testers and support staff looking to run virtual machines (VMs) locally. As a result, the only management required is the ability to build and run the VMs and, perhaps, organise them into groups, take backups, clone and copy virtual machines and so on. All this will typically be done interactively by the user of the host PC.

Server virtualisation tends to be used in quite a different way. It can, and often is, used for development and testing purposes but will more often be deployed in a production server environment to maximise and consolidate hardware resources.

Servers tend to be locked away and left unattended, so it is important to monitor VM activity, dynamically allocate and re-assign resources to balance VM workloads, and move virtual machines from one host to another as seamlessly as possible. Indeed, the holy grail of server virtualisation is ‘live’ migration, where VM workloads can be moved from server to server without having to be stopped and re-started.

Some of these facilities can be found in the free products, but none offers a complete solution. Most only let you manage a single host server unless you buy, sometimes quite costly, add-on management tools. That’s not a major issue in a lot of small businesses, where it’s common to have just one or two physical servers hosting important, but far from mission-critical, virtual machines. This is mainly because, in such cases, it’s easy enough to arrange for backup s ystems to be available to cope with hardware problems and to manually monitor, fine tune and migrate VMs as needed using the tools included with the free products.

The downside of this hands-on approach is that it takes a lot of work and doesn’t suit everyone, especially as the number of servers rises. When that happens management add-ons become increasingly important, although even with the largest and most complex of deployments you may not need everything on offer.

So, we’ve summarised what is included as standard in the leading free server virtualisation products (from VMware, Microsoft and Citrix), and given an idea of what you might need to add for each one to make larger deployments easier to manage.

The VMware story
Virtualisation market leader, VMware (a part of EMC), has two free server products for small businesses: VMware Server and ESXI.

The main difference between the two is that VMware Server is implemented as an application, hosted by a standard Windows or Linux server OS, whereas ESXI is a hypervisor, loaded straight onto the server with no need for a host operating system.

In terms of core virtualisation facilities ESXI is the more scalable. In effect, you’re getting the same hypervisor behind the company’s large enterprise solution, VMware Infrastructure. But VMWare Server is good, capable of hosting virtual machines running a variety of 32-bit and 64-bit operating systems, including Windows Server 2008 and Red Hat Enterprise Linux 5. Each VM can have up to two virtual processors, 8GB of Ram and 10 virtual network interfaces.

With VMware Server the host can support up to 64 virtual machines, more than enough for most small businesses. However, you get very little in the way of management, beyond the ability to remotely create, start and stop VMs and take backup snapshots.
And it’s much the same story with ESXI where, as with VMware Server, you get a web-based console that lets you manage VMs on a single host.

In order to do more than that, you need the VMWare Virtualcenter Console, included as part of the Virtual Infrastructure solution. Depending on what you can afford, you will then be able to manage both VMware Server and ESXI systems with (where the hypervisor is involved) support for live migration of virtual machines (VMware calls this VMotion) plus other tools such as dynamic allocation of host resources and high availability failover.