Cloud Computing

The following attributes can characterize the cloud

• On-demand self-service
• Broad Network access and accessible with different devices
• Resource pooling and multi-tenant
• Rapid elasticity
• Measured services report on resource usage

The Cloud Provider provides these shared resources.

• IaaS: Infrastructure as a Service
• PaaS: Platform as a Service
• SaaS: Software as a Services

See also Cloud Service Models - snippset

• Public Cloud: Cloud service provided by a third-party provider, hardware can be shared amongst multiple clients
• Private Cloud: Hardware is only used by a single company, which often owns the hardware and datacenter
• Hybrid Cloud: Combination of public and private cloud with automation and orchestration between the two
• Community Cloud: Infrastructure is shared between several organizations from a specific community with common concerns (security, compliance, jurisdiction, etc.)

Companies use different cloud environments for legacy reasons or leverage the right cloud service based on specific needs or requirements like data sovereignty or other regulation.

Reasons for a hybrid and multi-cloud strategy

• Regulatory and data sovereignty (patient record or financial records needs to stay in a country or region)
• Low latency and edge workloads (up to the cloud, process, and back down)
• Application and datacenter modernization
• Business continuity and resilience (backup of data and app into another cloud, no lock-in)
• Freedom to use more than one public cloud
• Acquisition
• Different offerings from different cloud providers

• What is Cloud Computing? Everything You Need to Know (techtarget.com)