How to monitor several sites for updates from one central site? I have several Drupal sites and wish to have one site list all of their "status" and available updates. So to start with I am trying to find how to get the available updates.

The central site has access to the databases of all of the others so I am hoping to pull info direct from there but I have no clue where to look.

Is there a table with such information that is auto updated on cron etc?
You can use Drupal Remote Dashboard module for this


  This module is for system administrators. It's a tool to monitor and manage any number of Drupal installations at once and it's built to be extensible by other modules. Since version 2.X this module also comes with the highest level of security where as all communication between the dashboard and each of the cores is AES encrypted, hence the dependency (see below). Optionally the monitoring data will be made visible in nice graphs if the Google Chart API is available.