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=== OpenVZ Applications ===
OpenVZ provides a comprehensive solutionm solution allowing to:
* Have hundreds of users with their individual full-featured containers sharing a single physical server;
* Provide each user with a guaranteed Quality of Service;
* Each Container can have its own configuration for the system and application software, as well as its own versions of system libraries. It is possible to install or customize software packages inside a container independently from other CTs or the host system. Multiple distributions of a package can be run on one and the same Linux box.
In fact, hundreds of servers may be grouped together in this way. Besides the evident advantages of such consolidation (increased facility of administration and the like), there are some you might not even have thought of, say, cutting down electricity bills by many times!
OpenVZ proves invaluable for IT educational institutions that can now provide every student with a personal Linux server, which can be monitored and managed remotely. Software development companies may use Containers for testing purposes and the like.
In this section we will try to let you form a more or less precise idea of the way the OpenVZ software operates on your computer. Please see the figure.
[[Image:OpenVZ technology.png|thumb|500px|Figure 1. OpenVZ 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 the OpenVZ software 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 just ''Nodes''), because they represent hardware units within a network.
The OpenVZ software allows you to flexibly configure various settings for the OpenVZ system in general as well as for each and every Container. Among these settings are disk and user quota, network parameters, default file locations and configuration sample files, and others.
OpenVZ stores the configuration information in two types of files: the global configuration file <code>/etc/vz/vz.conf</code> and Container configuration files <code>/etc/vz/conf/''CTID''.conf</code>. The global configuration file defines global and default parameters for Container operation, for example, logging settings, enabling and disabling disk quota for Containers, the default configuration file and OS template on the basis of which a new Container is created, and so on. On the other hand, a Container configuration file defines the parameters for a given particular Container, such as disk quota and allocated resources limits, IP address and host name, and so on. In case a parameter is configured both in the global OpenVZ configuration file, and in the Container configuration file, the Container configuration file takes precedence. For a list of parameters constituting the global configuration file and the Container configuration files, see {{man|vz.conf|5}} and {{man|vpsctid.conf|5}} manual pages.
The configuration files are read when the OpenVZ software and/or Containers are started. However, OpenVZ standard utilities, for example, <code>vzctl</code>, allow you to change many configuration settings "on-the-fly", either without modifying the corresponding configuration files or with their modification (if you want the changes to apply the next time The OpenVZ software and/or Containers are started).