SWsoft Virtuozzo for Linux 3 review

Virtuozzo lets you run several virtual servers on a single host system. Linux users already have a choice of User Mode Linux, Xen or VMware’s Server software. But these systems adopt a virtual machine approach, creating an environment that fools the guest operating system that it’s running on real hardware. Using VMware Server, for example, it’s possible to run Windows 2000 Server on a Linux system. This flexibility comes at a price, however, and the processing overheads of providing a virtual machine are such that a system can run out of steam when several virtual systems are running. Virtuozzo uses a different approach, making virtual copies of the OS and software, and using these to create Virtual Private Servers (VPSes). Since there are no virtual machine overheads, the hardware can support many more virtual servers before running out of processing power.

Virtuozzo uses a system of templates to create and configure a VPS and its associated applications. Templates ensure an application or OS will only create one copy on disk and one copy in memory for all the VPSes that may use them. This minimises the use of resources and allows much higher numbers of virtual servers to run than might otherwise be possible. Each VPS runs with its own IP address and provides a complete working environment that supports users and services and operates in the same way as any other Linux system. Application software can also be installed into an individual VPS in the same way as you would on a normal server. But the application will need a copy on disk and in memory for each VPS that will use it. It won’t be shared across multiple servers.

There are two management interfaces on offer. The Virtuozzo Management Console, which runs on Windows, gives control over all the management, system setup and monitoring features. It’s used to access the host systems and all the VPS installations running on them. With this software, you can upload templates, manage VPS groups and create legions of virtual servers with a few mouse clicks. The browser-based Virtuozzo Power Panel software (VZPP) gives access to routine maintenance and monitoring tasks, such as creating backups, restoring and recreating any VPS. VZPP can run on Internet Explorer or Mozilla Firefox browsers, and is used to manage and monitor an individual VPS by using its IP address. Since each VPS has its own set of users and groups, each one can be assigned to a different management user if required. A secure shell facility gives access to the command line for complete control of the VPS.

The software can reallocate resources to meet changing loads. Separate VPSes can be created to handle end-of-month or end-of-year scenarios, or other infrequent or unusual situations. Each one can then be stored until required, saving time and resources. Of course, all the servers must be running similar operating systems. A Linux host can only support virtual servers running Linux. But this is no problem in production environments, where the need is to run stable systems on several servers and process large volumes of traffic with various workloads and mixes. In these kinds of scenarios, Virtuozzo does the job very well.