Technical isolation

When defining functional boundaries we have many degrees of freedom. There is a lot of good advice and a few hard and fast rules, but for the most part you rely on your domain expertise and practical experience. When it comes to technical isolation the realities of cloud computing are a bit more strict and make isolation equally elusive. Shared Nothing is certainly a guiding concept, but in practice there tend to be a lot of leaks. To provide the necessary bulkheads we need to consider regions and availability zones, cloud accounts and providers, deployment units and resource management, and data isolation.