OpenVZ in Detail

[eUKShane]

What is OpenVZ ?

OpenVZ is a complete server automation and virtualization solution developed by SWsoft. OpenVZ creates multiple isolated Virtual Private Servers (VPS Hostings) on a single physical server to share hardware and management effort with maximum efficiency. Each VPS Hosting performs and executes exactly like a stand-alone server for its users and applications as it can be rebooted independently and has its own root access, users, IP addresses, memory, processes, files, applications, system libraries, and configuration files. Light overhead and efficient design of OpenVZ makes it the right virtualization choice for production servers with live applications and real-life data.

The basic OpenVZ VPS Hosting capabilities are:

Dynamic Real-time Partitioning –
Partition a physical server into tens of VPS Hostings, each with full dedicated server functionality.
Resource Management –
Assign and control VPS Hosting resource parameters and re-allocate resources in real-time.
Mass Management -
Manage a multitude of physical servers and Virtual Private Servers in a unified way.

Basics of OpenVZ and VPS Hosting Technology



This figure presumes that you have a number of physical servers united into a network. In fact, you may have only one dedicated server to effectively use OpenVZ for the needs of your network. If you have more than one OpenVZ-based physical server, each one of the servers will have a similar architecture. In OpenVZ terminology, such servers are called Hardware Nodes (or HN, or just Nodes), because they represent hardware units within a network.

OpenVZ is installed on Fedora Core 3 or 4 or Red Hat Enterprise Linux 4 configured in a certain way. For example, such customized configuration shall include the creation of a /vz partition, which is the basic partition for hosting Virtual Private Servers and which must be way larger than the root partition. This and similar configuration issues are most easily resolved during Linux installation on the Hardware Node.

OpenVZ is installed in such a way that you will be able to boot your computer either with OpenVZ support or without it. This support is presented as “OpenVZ” in your boot loader and shown as OpenVZ Layer in the figure above.

However, at this point you are not yet able to create Virtual Private Servers. A Virtual Private Server is functionally identical to an isolated standalone server, having its own IP addresses, processes, files, users, its own configuration files, its own applications, system libraries, and so on. Virtual private servers share the same Hardware Node and the same OS kernel. However, they are isolated from each other. A Virtual Private Server is a kind of ‘sandbox’ for processes and users.
Different Virtual Private Servers can run different versions of Linux (for example, SuSE 9.2 or Fedora Core 4 and many others). Each VPS Hosting can run its own version of Linux. In this case we say that a VPS Hosting is based on a certain OS template. OS templates are packages shipped with OpenVZ. Before you are able to create a Virtual Private Server, you should install the corresponding OS template in OpenVZ. This is displayed as OpenVZ Templates in the scheme above.
After you have installed at least one OS template, you can create any number of VPS Hostings with the help of standard OpenVZ utilities, configure their network and/or other settings, and work with these VPS Hostings as with fully functional Linux servers.

Best Regards,
UKShane
http://www.eukhost.com