Na documentação / Perguntas frequentes sobre o Azure :
My roles instances restarted without me doing anything.
Service healing occurs automatically when the Windows Azure detects problematic nodes and moves role instances to new nodes. When this occurs, you might see your role instances restarting automatically.
To find out if service healing occurred:
In the Management Portal, click the deployment of your hosted service.
In the Properties pane of the Management Portal, review the information and determine if service healing occurred during the time you observed the roles restarting.