Cloud Computing is a model of on-demand access of computing resources from a shared pool of resources like processing, memory, network, storage, applications and other computing services that can be rapidly provisioned and released.
Essential Characteristics of Cloud Computing
On-demand self-service – Provisioning of computing service can be done automatically without human intervention.
Broad network access – The cloud resources can be accessed through any type of network across from various types of client platforms.
Resource pooling – The computing resources (CPU, memory, storage, network) are pooled and are available for provisioning anytime on demand.
Rapid elasticity – The provisioned computing resources can scale up and down depending on the demand and requirements.
Measured service – The computing resources usage can be controlled by leveraging metering capabilities.
Cloud Service Models
Infrastructure as a Service (IaaS) – Consumer can provision processing, storage, networks, and other fundamental computing resources. The consumer does not manage or control the underlying cloud infrastructure but has the control over operating systems, storage, and deployed applications.
Platform as a Service (PaaS) – Consumer can provision applications developed using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, but has control over the deployed applications.
Software as a Service (SaaS) – Consumer can use provider’s applications running on a cloud infrastructure. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage and the application.
Cloud Deployment Models
Public Cloud – The cloud infrastructure is owned and operated by third party Service Provider (SP) and is present in the location owned by the Service Provider.
Private Cloud – The cloud infrastructure is owned by the organization (consumer) and present in their location. The cloud can be operated either by the organization or third party service operator.
Hybrid Cloud – This is combination of both public and private cloud. The clouds are internconnected and data is moved between the cloud.
Community cloud – The cloud infrastructure is shared by multiple organizations.
Benefits of Cloud Storage
Cost savings – Using cloud brings cost saving as the computing resources are provisioned on demand only when required with only the required amount of resources.
Flexibility – Cloud brings lot og flexibility of provisioning, de-provisioning, managing, monitoring as it’s pay as use service.
Scalability – The computing resources can scale up and down as required.
Efficiency – Cloud computing is efficient as there is end to end automation and orchestration of deployment of the resuources.
High Availability – Cloud computing high avaialibility with least downtime as the computing resources are spread across geography with redundancy and failover.
Agility – Cloud computing can be provisioned and deployed based on the business needs anytime.
Reachability – The cloud infrastructure and it’s resources can be accessed anytime through wide range of network technologies and various computing clients.
Quick Provisioning – The cloud computing resources can be provision very quickly due to it’s virtualization propertly.
Reference
NIST SP 800-145, The NIST Definition of Cloud Computing
Evaluation of Cloud Computing Services Based on NIST 800-145