What is Virtuozzo...

Virtuozzo is a software application for enterprise server virtualization that allows an administrator to create virtual environments on a host computer at the operating system (OS) layer.

Instead of having one physical machine run multiple operating systems simultaneously, as the virtual machine model used by VMware and Microsoft Virtual Server or XEN does, Virtuozzo approaches virtualization by running a single OS kernel as its core and exporting that core functionality to various partitions on the host. Each of the partitions effectively becomes a stand-alone entity called a virtual private server (VPS).

Virtuozzo comes with a proprietary Kernel Service Abstraction Layer (KSAL) that manages access to the kernel and prevents any single VPS from bringing the entire physical server down. It also has a proprietary file system to completely isolate the partitions, a security precaution that prevents a software fault in one partition from impacting an application or data in another partition.

Every VPS has its own network address and its own set of login credentials, system processes and daemon services. Because the underlying operating system is always running, each VPS can be rebooted independently and data can be migrated from one virtual environment to another on a live host. This capacity -- which is not possible with the virtual machine model -- is one reason why Virtuozzo has the reputation for being a good choice for production servers working with live data and applications.

Virtuozzo's architecture eliminates system calls between layers, which reduces CPU usage overhead dramatically. Common binaries and libraries on the same host machine can be shared, making it possible for administrators to put literally thousands of VPSs on the same machine, each functioning as a stand-alone server.

Administrators using Virtuozzo have three management options: the command line, Virtual Management Center (a GUI interface for management and monitoring) and Virtual Control Center (a Web-based interface for remote access).

Virtuozzo is created and distributed by SWSoft. In 2006, SWsoft released the core of Virtuozzo under the GNU GPL (General Public License) in an open-source project called OpenVZ.

Commands
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vzctl	Utility to control Containers.
vzlist	Utility to view a list of Containers existing on the Node with additional information.
vzquota	Utility to control Virtuozzo Containers disk quotas.

Licensing utilities allow you to install a new license, view the license state, generate a license request for a new license:

vzlicview	Utility to display the Virtuozzo license status and parameters.
vzlicload	Utility to manage Virtuozzo licenses on the Hardware Node.
vzlicupdate	Utility to activate the Virtuozzo Containers installation, update the Virtuozzo licenses installed on the Hardware Node, or transfer the Virtuozzo license from the Source Node to the Destination Node.

Container migration tools allow to migrate Containers between Hardware Nodes or within one Hardware Node:

vzmigrate	Utility for migrating Containers from one Hardware Node to another.
vzmlocal	Utility for the local cloning or moving of the Containers.
vzp2v	Utility to migrate a physical server to a Container on the Node.
vzv2p	Utility to migrate a Container to a physical server.

Container backup utilities allow to back up and restore the Container private areas, configuration files, action scripts, and quota information:

vzbackup	Utility to back up Containers.
vzrestore	Utility to restore backed up Containers.
vzabackup	Utility to back up Hardware Nodes and their Containers. As distinct fromvzbackup, this utility requires the Parallels Agent software for its functioning.
vzarestore	Utility to restore backed up Hardware Nodes and Containers. As distinct from vzrestore, this utility requires the Parallels Agent software for its functioning.

Template management tools allow the template creation, maintenance and installation of applications into a Container:

vzpkg	Utility to manage OS and application EZ templates either inside your Containers or on the Hardware Node itself.
vzmktmpl	Utility to create OS and application EZ templates.
vzveconvert	Utility to convert Containers based on Virtuozzo standard templates to EZ template-based Containers.
vzpkgproxy	Utility to create caching proxy servers for handling OS and application EZ templates.
vzrhnproxy	Utility to create RHN proxy servers for handling the packages included in the RHEL 4 and RHEL 5 OS EZ templates.
vzpkgls	Utility to get a list of templates available on the Hardware Node and in Containers.
vzpkginfo	Utility to get the information on any template installed on the Hardware Node.
vzpkgcreat	Create a new package set from binary RPM or DEB files.
vzpkgadd	Utility to add a new template to a Container.
vzpkglink	Utility to replace real files inside a Container with symlinks to these very files on the Node.
vzpkgrm	Utility to remove a template from a Container.
vzpkgcache	Update a set of preinstalled Container archives after new template installation.

Supplementary tools perform a number of miscellaneous tasks in the Hardware Node and Container context:

vzup2date	Utility to update your Virtuozzo software and templates.
vzup2date-mirror	Utility to create local mirrors of the Virtuozzo official repository.
vzfsutil	Utility for the VZFS optimization and consistency checking.
vzcache	Utility to gain extra disk space by caching the files identical in different Containers.
vzsveinstall	Utility to create the Service Container on the Hardware Node.
vzsveupgrade	Utility to update the packages inside the Service Container.
vzps and vztop	Utilities working as the standard ps and top utilities, with Container-related functionality added.
vzsetxinetd	Utility to switch some services between a standalone and xinetd-dependent modes.
vzdqcheck	Print file space current usage from quota's point of view.
vzdqdump andvzdqload	Utilities to dump the Container user/group quota limits and grace times from the kernel or the quota file or for loading them to a quota file.
vznetstat	Utility that prints network traffic usage statistic by Containers.
vzcpucheck	Utility for checking CPU utilization by Containers.
vzmemcheck	Utility for checking the Hardware Node and Container current memory parameters.
vzcalc	Utility to calculate resource usage by a Container.
vzcheckovr	Utility to check the current system overcommitment and safety of the total resource control settings.
vzstat	Utility to monitor the Hardware Node and Container resources consumption in real time.
vzpid	Utility that prints Container id the process belongs to.
vzsplit	Utility to generate Container configuration file sample, "splitting" the Hardware Node into equal parts.
vzcfgscale	Utility to scale the Container configuration.
vzcfgvalidate	Utility to validate Container configuration file correctness.
vzcfgconvert	Utility to convert Virtuozzo 2.0.2 Container configuration files to Virtuozzo 2.5.x format.
vzstatrep	Utility to analyze the logs collected by vzlmond and to generate statistics reports on the basis of these logs (in the text and graphical form).
vzreport	Utility to draw up a problem report and to automatically send it to the Parallels support team.
vzhwcalc	Utility to scan the main resources on any Linux server and create a file where this information will be specified.
vzveconvert	Utility to convert the Containers based on Virtuozzo standard OS templates to the EZ template-based ones.
vznetcfg	Utility to manage network devices on the Hardware Node.
vzmtemplate	Utility to migrate the installed OS and application templates from the one Hardware Node to another.