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Cloud Computing

The National Institute of Standards and Technology (NIST) defines cloud computing as a model for providing on-demand network access to computing resources that can be rapidly provisioned and released.

Core Concepts​

  • On-demand access: Users can provision resources like virtual machines and storage as needed, typically paying only for what they use.
  • Resource pooling: Cloud providers maintain large pools of resources (servers, storage, etc.) that are shared among many users for efficiency.
  • Elasticity: Cloud services can automatically scale resources up or down to match demand.
  • Pay-as-you-go pricing: Users are billed based on actual resource usage, which avoids large upfront costs for hardware.

Cloud Service Models​

Service models define the level of management and control you have over your cloud resources.

  • Infrastructure as a Service (IaaS): Provides virtualized computing resources like virtual machines, storage, and networking. You manage the operating system and applications.
    • AWS Examples: EC2, S3, VPC.
  • Platform as a Service (PaaS): Offers a platform to build, deploy, and manage applications without handling the underlying infrastructure.
    • AWS Examples: AWS Lambda, Elastic Beanstalk, RDS.
  • Software as a Service (SaaS): Delivers ready-to-use software applications over the internet via subscription.
    • General Examples: Microsoft 365, Netflix, Slack.
  • Function as a Service (FaaS) / Serverless: Allows you to run code in response to events without provisioning or managing servers.
    • AWS Example: AWS Lambda.

Cloud Service Model

Cloud Deployment Models​

Deployment models define where the cloud infrastructure is located and who has access to it.

  • Public Cloud: Services are owned by a third-party provider (like AWS) and delivered over the public internet to any user.
  • Private Cloud: The infrastructure is dedicated to a single organization, providing greater control and security. It can be hosted on-premises or by a third party.
  • Hybrid Cloud: Combines public and private clouds, allowing organizations to run workloads in the most appropriate environment. This is often used for disaster recovery or handling peak demand.