Discuss the current HA cluster stack and its usage in OpenStack and finish with the merges of newest upstream changes.

Additionally, discuss the adoption of Pacemaker Cloud [1].

"The Pacemaker Cloud project provides high levels of service availability for high scale cloud deployments. Our approach to high availability is to detect failures, isolate failures, followed by restart of the failed components. When repeated component failures occur the software escalates those failures into failures of higher level components."
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