Installation guide

Templates Overview

Parallels Virtuozzo Containers Templates

Overview

A template in Parallels Virtuozzo Containers is a set of application files and registry settings installed

on the Host operating system in such a way as to be usable by any Container by mounting over

Virtuozzo File System. The Parallels Virtuozzo Containers software provides tools for creating

templates, installing and removing them on/from the Hardware Node, adding them to a Container,

and so on. Using templates lets you

• Securely share the RAM among similar applications running in different Containers to save

hundreds of megabytes of memory.

• Securely share the files comprising a template among different Containers to save gigabytes of

disk space.

• Install applications and patches simultaneously in many Containers.

• Use different versions of an application on different Containers (for example, perform an

upgrade only in certain Containers).

There are two types of templates in Parallels Virtuozzo Containers. These are OS templates and

application templates. An OS template is an operating system and the standard set of applications

to be found right after the installation. Parallels Virtuozzo Containers uses OS templates to create

new Containers with a preinstalled operating system. An application template is a set of

repackaged software packages optionally accompanied with configuration scripts. Parallels

Virtuozzo Containers uses application templates to add extra software to the existing Containers.

For example, you can create a Container on the basis of the redhat OS template and add the

MySQL application to it with the help of the mysql template.

Some of the operations you can perform on templates are listed below:

• creating your own application templates

• uploading new templates to the Hardware Node

• listing the templates currently installed on the Hardware Node

• installing templates on and removing them from the Hardware Node

• adding templates to any number of Containers

• removing templates from the Hardware Node

• removing templates that are not needed any more from Containers

• migrating templates from the Source Node to the Destination Node

All these operations are described in the following chapters in detail.