1. Introduction : 1.5 Service Characteristics
1.5 Service Characteristics
The following essential cloud service characteristics are defined by the National Institute of Standards and Technology:
*On-demand self-service – A consumer can unilaterally provision computing capabilities as needed, automatically, without requiring human interaction with each service’s provider.
*Broad network access – Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin client or thick client platforms.
*Resource pooling – The provider’s computing resources are pooled to serve multiple consumers, using a multitenant model with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence because the subscriber generally has no knowledge of or control over the exact location of the provided resources, but might be able to specify location at a higher level of abstraction.
*Rapid elasticity – Capabilities can be provisioned to scale out quickly and to be released rapidly, in some cases automatically. Rapid elasticity allows resources both to scale out and scale in quickly. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time.
*Measured service – Cloud systems automatically control and optimize resource usage by leveraging a metering capability at some level of abstraction appropriate to the type of service. Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.
Figure 4. Service Characteristics
To deliver business solutions using vCloud services, the vCloud infrastructure must have the following additional essential characteristics:
*Standardized – Homogeneous infrastructure delivered as software services across pools of standard, x86 hardware. Homogeneity eliminates unnecessary complexity caused by operating system silos and the redundant tools and skill sets associated with them. It also eliminates costly, special-purpose hardware and enables a single, scalable approach to backup and recovery.
*Holistic – A platform optimized for the entire datacenter fabric, providing comprehensive infrastructure services capable of supporting any and all applications. A holistic infrastructure is ready and able to support any workloads, with complete flexibility to balance the collective application demands, eliminating the need for diverse technology stacks.
*Adaptive – Infrastructure services provided on demand, unconstrained by physical topology and dynamically adapting to application scale and location. The infrastructure platform configures and reconfigures the environment dynamically, based on collective application workload demands, enabling maximum throughput, agility, and efficiency.
*Automated – Built-in intelligence automates provisioning, placement, configuration, and control, based on defined policies. Intelligent infrastructure eliminates complex, brittle management scripts. Less manual intervention equates to scalability, speed, and cost savings. Intelligence in the infrastructure supports vCloud-scale operations.
*Resilient – A software-based architecture and approach compensates for failing hardware, providing failover, redundancy, and fault tolerance to critical operations. Intelligent automation provides resiliency without the need for manual intervention.