Quattor

Quattor is a large scale fabric management system for managing medium to very large (>1000 node) clusters. It is largely similar to LCFG and is particularly well suited to Grid computing sites. Quattor was developed at CERN for use in the LCG project. Quattor is in used by many Grid sites around the world today.

A Grid site will use profiles to configure machines (virtual and physical) using a language called PAN, this is then compiled using panc and ant, and creates XML profiles, which the NCM (node configuration manager) on each machine uses to configure the machine. Typical configuration includes software package installation and machine settings (grub for instance).

What is Quattor?
Quattor is software allowing to deploy and manage configuration of a huge number of systems, consistently and efficiently. It has been developed by EDG project, as part of WP4 effort (Fabric Administration).

Quattor aims to produce flexible but reproducible configurations. Instead of using imaging technology that is very efficient for initial installation but doesn’t allow to reconfigure the system after installation, Quattor is based on a description of the machine configuration using a language developed as part of Quattor: PAN. This language allows an efficient, abstract description of the final machine configuration.

Configuration description is organized in templates. Templates can be used to describe basic services or configuration elements and are assembled to produce one machine specific configuration.

The configuration is produced by compiling templates. This compilation phase is a key feature of Quattor: it ensures consistency of the configuration and warranty that the configuration will be implemented with success.

This configuration is enforced on each node by a Quattor client that receive notification of any configuration changes applying to the current node and takes the appropriate actions, based on the difference between current and new configuration, through the execution of components.

Each component (implemented as a Perl script) is an engine responsible of one part of the configuration (account creation, filesystem management, gridmap management...). This engine receives its currents input from the configuration produced from templates and needs site customization.

Configuration compiled from templates can also be used to configure Red Hat installer (Anaconda/Kickstart) for initial installation of a system through PXE.

With these features, Quattor is unique installation and configuration management tool that provide a consistent and flexible way to manage machine configuration and apply configuration changes at any time, not just during installation.

Quattor is particularly powerful at managing a huge number (100 or 1000+ machines) sharing some common configuration. For example in the Grid context where you manage a large number of worker nodes all having the same configuration, you can change configuration on a worker node (e.g. add an AFS client) by just adding a few lines in a template and recompiling configuration. This will be deployed in a few minutes on all the worker nodes.

See also

* Comparison of open source configuration management software

External links

* [http://www.quattor.org/ Quattor Homepage]