Definition from National Institute of Standards and Technology (NIST): A model for enabling convenient, on-demand network access to a shared pool of configurable computing resources, such as networks, servers, storage, applications, and services, that can be rapidly provisioned and released with minimum effort or service provider interaction.
1. Virtualization: users don’t have to be concerned with servers or their location.
2. Distributed system (includes grid computing)
3. Sub-classification, core service models
- IaaS (Infrastructure as a Service): Suitable for IT professionals. Most complex.
- PaaS (Platform as a Service): Suitable for developers. Medium complex.
- SaaS (Software as a Service): Suitable for the company with small number of IT staffs. And deploy the applications for instance. Simple.
- CaaS (Communication as a Service): Easiest to use. Limited to several domains like the IP phone, Video Conference, etc.
4. Key technology drivers
- Cloud datacenters
- Virtualization
- Cloud API
- Cloud storage
- Cloud database
Cloud makes reference to: Abstraction and Virtualization.
Drawbacks
- Security
- Less control
- Vendor lock-in: Difficult to change vendor and move to another cloud
Price: pay-as-you-go.