Cloud Service Models

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A Cloud service model is the classification of the provision of cloud services and the limit of the cloud service provider’s responsibility as software, platform, infrastructure, and so on.

• often differentiated on the level of complexity and preconfiguration provided
• common models are infrastructure, software, platform, and desktop

Software as a Service

Software as a service (SaaS) is a cloud service model that provisions fully developed application services to users.

• Rather than purchasing software licenses for a given number of seats,
  • access software hosted on a supplier’s servers on a pay-as-you-go arrangement
• applications can be developed and tested in the cloud without the need to test and deploy on client computers

Platform as a Service

Platform as a service (PaaS) is a cloud service model that provisions application and database services as a platform for development of apps.

• provides resources somewhere between SaaS and IaaS
• provides a platform for organizations to run their own application code
  • without worrying about server configuration
• provides:
  • servers and storage network infrastructure (as per IaaS)
  • a multi-tier web application/database platform on top
• could be based on Oracle® or MS SQL or PHP and MySQL™
• E.g.,
  • Oracle Database
  • Microsoft Azure SQL Database
  • Google App Engine™
• would not be configured to run an application
  • own developers would have to create the software that runs using the platform
  • e.g., CRM or e‑commerce application
• service provider responsible for:
  • the integrity and availability of the platform components
• you are responsible for:
  • the security of the application you created on the platform
• Function as a Service (FaaS) is a common PaaS capability

Infrastructure as a Service

Infrastructure as a service (IaaS) is a cloud service model that provisions virtual machines and network infrastructure.

• is a means of provisioning IT resources quickly
  • e.g.,
    • servers
    • load balancers
    • storage area network (SAN) components
• Rather than purchase these components and the Internet links they require,
  • you deploy them as needed from the service provider’s datacenter
• E.g.,
  • Amazon Elastic Compute Cloud
  • Microsoft® Azure® Virtual Machines
  • OpenStack®
• Infra capability types:
  • Virtualized servers that run on shared hardware
  • Block storage available as disk volumes
  • Object storage as files in buckets
  • Networking capacity to connect servers
  • Orchestration capabilities to automate administration of cloud infra

Difference between IaaS and PaaS

• The difference lies in who manages the switching, routing, and operating systems
  • If the client is responsible for licensing the operating system and managing the back-end networking, it is considered IaaS
  • If the cloud service provider is responsible for licensing the operating systems and back-end storage and networking, it is considered PaaS

Third-Party Vendors

Third-party vendors are external entities that provide organizations with goods, services, or technology solutions.

• refer to the providers offering cloud services to businesses using infrastructure-, platform-, or software-as-a-service models
• As a third party, careful consideration is paramount regarding:
  • cloud service provider selection
  • contract negotiation
  • service performance
  • compliance
  • and communication practices
• Organizations must adopt robust vendor management strategies to
  • mitigate cloud platform risks
  • ensure service quality
  • and optimize cloud deployments
• Organizations must assess the security practices implemented by vendors to protect their sensitive data
  • including data encryption, access controls, vulnerability management, incident response procedures, and regulatory compliance
• Orgs are responsible for ensuring compliance with data privacy requirements
  • especially if they handle personally identifiable information (PII) or operate in regulated industries
• Vendor lock-in makes switching to alternative vendors or platforms challenging or impossible
  • to mitigate vendor lock-in risks, must carefully evaluate:
    • data portability
    • interoperability
    • and standardization
  • multi-cloud or hybrid cloud deployments can:
    • provide flexibility
    • reduce reliance on a single vendor

Service-level agreements (SLAs) are contractual agreements between organizations and cloud service providers that outline the expected levels of service delivery.

• define:
  • metrics
    • such as uptime, performance, and support response times
  • penalties or remedies if service levels are not met
• provide a framework to hold vendors accountable for delivering services at required performance levels