Date Added: May 2012
Cloud technology is evolving at a rapid pace with innovation occurring throughout the software stack. While updates to Software-as-a-Service (SaaS) products require a simple push of code to the production servers or platform, updates to the Infrastructure-as-a-Service (IaaS) or Platform-as-a-Service (PaaS) layers require more intricate procedures to prevent disruption to services at higher abstraction layers. In this paper, the authors address the need for rolling upgrades to PaaS systems. They do so with the App-Scale PaaS, which is a multi-application, multi-language, multi-infrastructure, and multi-datastore platform.