In large deployments, some piece of Nova is deployed almost everywhere. Until recently, the story for how you upgrade to using a newer version of this fast-paced project has been turn off the cloud" -- an unacceptable answer for something that aims to be deployed at a scale large enough to make such a plan unfeasible. Over the last several releases, "upgrade-ability" has been a major theme of development for the Nova team, shooting for both reduced downtime of core components and elimination of the need to "turn off the cloud" while thousands of nodes are upgraded atomically. This talk will cover the incremental steps we have made in recent cycles, as well as reveal the major new capability that the Icehouse release brings to the table. "
