About Plesk Expand

Understanding Basic Concepts of Plesk Expand

The main thing about Plesk Expand is that it is intended to extend Plesk™ functionality and is considered to be an addon application for Plesk™. Plesk Expand cannot be used on its own, it requires at least two Plesk servers to operate.

Below, we provide short descriptions of Plesk™ and Plesk Expand.

Plesk™ is a control panel designed to automate all aspects of your hosting business and deliver superior flexibility and stability to your customers. It enables users to create and remotely manage hundreds of virtual hosts through an easy-to-use, intuitive interface, without in-depth technical knowledge of web hosting technologies. The extensive set of Plesk features allows you to completely automate product installation, enrich self-administration capabilities for your clients, and minimize the number of support calls.

Plesk Expand is the hosting automation software that unites multiple Plesk servers on a single hosting platform. It allows hosting service providers to administer several Plesk servers from one centralized point: the Plesk Expand control panel. Using Plesk Expand, the administrator can centrally manage all Plesk client accounts, domains and other objects registered on different Plesk servers, without having to log in to these servers. Plesk Expand offers centralized administration of major client services - such as e-mail, DNS and database management - across all Plesk Expand servers, thus allowing to effectively balance the workload. Specialized user roles - such as the Plesk Expand reseller and Plesk Expand client - allow the administrator to configure and sell a number of advanced web hosting reseller packages. Plesk Expand can be easily integrated with the provider's infrastructure through special APIs (Application Programming Interfaces).

Plesk Expand Operation Principles

Plesk Expand operation model is shown on the following figure:

Plesk Expand Operation Diagram

Plesk Expand User roles and basic objects are described further.

Plesk Expand objects

Plesk Expand objects are Plesk servers and accounts registered on Plesk servers, which are managed by Plesk Expand users.

There are the following kinds of objects in Plesk Expand:

Plesk Server. A hosting server running Plesk ^TM control panel software (either Plesk for Windows or Plesk for Linux/Unix) registered in Plesk Expand.
Plesk Server Group. Several Plesk servers to which common rules or features are assigned by Administrator, or which are assigned to one Reseller.
Plesk client is a Plesk client account residing on one of Plesk servers registered in Plesk Expand. You can grant Plesk clients access to Plesk control panel, where he can manage his or her account and domains.
Domain is a virtual host on the Internet owned by a Plesk client, Expand Reseller or Expand client. For each domain, you can create a Domain Administrator account allowing to manage the domain in the Plesk control panel.

Plesk Expand users

Plesk Expand Users have certain rights and privileges on certain Plesk objects they own. Plesk Expand users have access to the Plesk Expand control panel, where they can manage their objects and accounts, within the limits and capabilities provided by their user role. There are the following user roles in Plesk Expand:

Administrator. A Plesk Expand user who has full rights to configure Plesk Expand and manage all its objects and user accounts.
Expand Reseller is a Plesk Expand user who owns and manages Plesk servers, groups of Plesk servers, Plesk client accounts and domains. Reseller has Administrator rights on all objects registered on Plesk servers which he or she owns.
Expand Client is a Plesk Expand user who owns and manages domains and Plesk clients in Plesk Expand. These domains and Plesk clients may be registered on several Plesk servers, including servers running different platforms (Plesk for Windows or Plesk for Linux/Unix).

Plesk Expand Centralized servers

Plesk Expand offers a set of distributed (or centralized) services. A distributed service is a service received by several Plesk servers remotely, from a single centralized dedicated server. Such a server (called a Centralized server) is allocated for providing this service to several or all objects registered on other Plesk servers. This allows to reduce the workload on each Plesk server, optimize the overall system performance, and helps to quickly and easily detect and resolve typical service issues. There are the following types of centralized servers in Plesk Expand:

Mail server. A Plesk server registered in Plesk Expand which operates as a centralized mail server for several Plesk servers.
DNS server. A Plesk or a non-Plesk server which operates as a centralized DNS server for several Plesk servers.
Database Server. A Plesk or a non-Plesk server which operates as a centralized database server for several Plesk servers.

Communication between Plesk Expand and Plesk servers

The communication between Plesk and Plesk Expand is provided by PSA API RPC, the data and command communication software. PSA API RPC should be installed on every Plesk/Linux server prior to registering it in Plesk Expand. On and Plesk/FreeBSD and Plesk for Windows servers there is no need to install PSA API RPC; it is included in the distribution package. For detailed information about PSA API RPC and instructions on its installation, see Plesk Expand Installation Guide here.