Cloud architecture is made up of many complex pieces. Compute, storage and network hardware, with a Cloud OS (IaaS control plane), and finally PaaS and SaaS layered on top.
Scale, automation, resource management, permission and policy management are the key challenges.
The hypervisor is NOT the Cloud OS, rather an essential component.
Large enterprises have shown that commodity hardware can lower costs. Design the application for commodity hardware and you can dramatically lower costs.
Network: topology no longer defines security, which now needs to be automatically and dynamically managed.
Federation: challenges are API, identity, data and application environment. Identity is the key.
Billing: metering, rating, and bill generation. The business is where the rating is.
Storage: Lots of data on enterprise platforms, opportunity to re-architect with low-cost storage. No one-size-fits all. The key is balance.
The cloud ecosystem has many components, many issues PER component. Focus on the key issues per component.