Infrastructure as a Service is a provision model in use by business to outsource hardware requirements. The cloud provider owns the equipment. The client pays for usage.
In defining Infrastructure as a Service we need to understand the specific features that a cloud platform provider supplies so that the service he provides is considered Infrastructure as a Service. To understand Infrastructure as a Service we need to look at the essential characteristics found in Infrastructure as a Service.
Infrastructure as a Service – Dynamic Scaling
Dynamic scaling enables the organisation to increase and decrease their hardware and processing requirement as and when required. Dynamic scaling may be driven by application requirements or seasonal computing demand of the organisation.
This is an important characteristic of Information as a Service; if customers need more resources they can get them immediately.
Infrastructure as a Service is offered in different flavours to organisations. Organisations may rent capacity based on an on-demand model with no contract. In other situations, the organisation signs a contract for a specific amount of storage and processing capacity.
A typical Information as a Service contract has a level of service guarantee included. The entry level may guarantee basic services while at the top-end a mirrored service with almost no change-of-service interruptions is the norm.
When organisations use computing resources from a cloud provider, the servers, storage, and all required IT infrastructure components are rented, based on the quantity of resources used and how long they’re in use.
In the private Information as a Service model, renting takes on a different focus. Organisations typically allocate usage fees to individual departments based on their weekly, monthly and yearly usage. With this flexibility, organisations can charge more of the budget to heavy users.
Infrastructure as a Service providers typically use a metering process to charge organisations based on the instance of computing consumed. An instance is defined as the CPU power and the memory and storage space consumed in an hour. When an instance is initiated, hourly charges begin to accumulate until the instance is terminated.
In addition to the basic per-instance charge, the cloud provider may include the following charges:
- Storage: A per-gigabyte (GB) charge for the persistent storage of data.
- Data transfer: A per-GB charge for data transfers. The fee may drop if you move large amounts of data during the billing month. Some providers offer free inbound data transfers or free transfers between separate instances on the same provider.
- Optional services: Charges for services such as reserved IP addresses, virtual private network (VPN), advanced monitoring capabilities, or support services.
Infrastructure as a Service is a provision model organisations use to outsource hardware required to perform their business. Many organizations select a hybrid approach — using private services in combination with public cloud services. This approach is attractive because an organisation can leverage its private cloud resources but use trusted public cloud services to manage peak loads.