Sometimes the question shows up why the change of configuration of a Windows Azure deployment does not take effect immediately (whatever that means ).
If you change the configuration (via the portal or via the management API) of your Windows Azure deployment then the change will happen almost immediately.
Well, not exactly.
The change will be rolled out to the instances using upgrade domains.
Source: Ryan Dunn’s TechEd 2010 presentation “Deploying, Troubleshooting, Managing and Monitoring Applications on Windows Azure”
For each upgrade domain a status change event will be raised and the instance can decide whether it will handle the change or whether it needs to be restarted.
Once the instances in that upgrade domain have reported that they are ready (either by handling the change, or by coming back online after restarting) then the fabric controller will move to the next upgrade domain.
Hope this helps.