Architecture

The Univention Management Console service consists of four components. The communication between these components is encrypted using SSL. The figure Architecture of UMC shows the architecture and the communication channels.

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Architecture of UMC

  • The UMC server is the core component. It provides access to the modules, manages the connection and verifies that only authorized users get access. The protocol used to communicate is the Univention Management Console Protocol (UMCP) in version 2.0.
  • The UMC HTTP server is a small web server that provides HTTP access to the UMC server. It it proxied behind an Apache web server, which handels the https: connection from the web frontend.
  • The UMC module processes are forked by the UMC server to provide a specific area of management tasks within a session.

Asynchronous Framework

All server-side components of the UMC service are based on the asynchronous framework Python Notifier, that provides techniques for handling quasi parallel tasks based on events. The framework follows three basic concepts:

Non-blocking sockets
Servers that should be handling several communication channels at the same time have to use so called non-blocking sockets. This is an option that needs to be set for each socket, that should be managed by the server. This is necessary to avoid blocking on read or write operations on the sockets.
Timer
To perform tasks after a defined amount of time the framework provides an API to manage timer (one shot or periodically).
Signals
To inform components within a process of a specific event the framework provides the possibility to define signals. Components being interested in events may place a registration.

Further details, examples and a complete API documentation for Python Notifier can be found at the website of the project Python Notifier website.