How to implement global messaging system in drupal for multiple sites? I have more than 100 sites that need to be maintained. So I am looking for way to put up a notice message for this group of sites. For example: We are having maintenance scheduled for tomorrow 10 PM. The message will be persisting for a time being for all the sites. 

Here I am assuming that there should be a central node from where we can push a message to all sites at once and delete when required.

So, I am looking for some help if there is already existing set of tools or way I can implement the workflow.


  I have tried Drupal Remote Dashboard module, the module seems to
  offer site monitoring from master node (site), but it doesn't seem to
  offer the global messaging option.
The nice thing in the "Drupal Remote Dashboard" module that you can run cron on your sites, so I would suggest that you build a custom messaging module that pull messages from master site (using cron to fire that).
- you can use services module to push your messages out