3. Cloud Computing and VMware vCloud : 3.1 VMware vCloud Requirements
   
3.1 VMware vCloud Requirements
According to the National Institute of Standards and Technology (NIST), the key components of a cloud are on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. VMware aligns with the definition of cloud as elastic, lightweight entry and exit, available over Internet protocols, and running on a shared infrastructure.
A cloud always starts with a shared, virtual infrastructure. If any resource is dedicated to only one customer, you have a managed hosting platform, not a cloud infrastructure. Similarly, it is not considered a cloud if there are manual procedures that must be performed by the cloud administrator or service provider to provision cloud resources following a consumer request. This is why workflow automation and orchestration are included as part of a vCloud solution.
The VMware vCloud blueprint follows these basic NIST requirements as the foundation for an IaaS cloud:
*A cloud must be built on a pooled, virtual infrastructure. Pools include not only CPU and memory resources but also storage, networking, and associated services.
*The cloud should provide application mobility between clouds, allowing the consumer to enter and leave the cloud easily with existing workloads. The ability to use existing consumer tools to migrate workloads to or from the cloud is highly desirable. Mobility of workloads between clouds requires cross-cloud resource management.
*The cloud should be open and interoperable, allowing the consumption of cloud resources over open, Internet-standard protocols. Access to cloud resources does not require any other specific network protocols or clients.
*Cloud consumers should pay only for resources they consume or commit to consuming.
*The cloud should be a secure, trusted location for running cloud consumer workloads.
*Cloud consumers should have the option and the ability to protect their cloud-based workloads from data loss.
*Cloud consumers are not responsible for the maintenance of any part of the shared infrastructure and do not need to interact with the cloud provider to maintain the infrastructure. They are not responsible for storage and network maintenance, ongoing cloud infrastructure patches, or business continuity activities. The cloud should be available to run high-availability workloads, and any faults occurring in the cloud infrastructure should be transparent to cloud consumers as a result of built-in availability, scalability, security, and performance guarantees.