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Cloud Service Models

Overview​

Cloud computing services are typically categorized into three main service models, each offering different levels of control & flexibility.

Service ModelYou ManageProvider ManagesExamples
On-PremiseEverythingNothingOwn data center, local servers
IaaS (Infrastructure as a Service)OS, Middleware, Runtime, Data, ApplicationsVirtualization, Servers, Storage, NetworkingAWS EC2, Azure VMs, Google Compute Engine
PaaS (Platform as a Service)Data, ApplicationsRuntime, Middleware, OS, Virtualization, Servers, Storage, NetworkingHeroku, Google App Engine, Azure App Service, Vercel
SaaS (Software as a Service)Configuration onlyEverythingGmail, Salesforce, Microsoft 365, Dropbox

On-Premise​

Definition​

On-premise (also called "on-prem") means running and managing all IT infrastructure locally within your own facilities. There is no cloud provider involved - your organization owns, operates, and maintains everything from the physical hardware to the applications.

What You Get​

  • Physical servers and hardware
  • Complete control over all layers
  • Data stays within your own facilities
  • No dependency on external providers

Responsibilities​

You manage:

  • Physical hardware (servers, storage, networking)
  • Virtualization
  • Operating systems
  • Middleware
  • Runtime environments
  • Applications
  • Data
  • Security, backups, disaster recovery

Use Cases​

  • Strict Compliance Requirements: Industries with strict data regulations (e.g. government, healthcare, finance)
  • Legacy Systems: Applications that cannot be migrated to the cloud
  • Low-Latency Needs: Systems requiring minimal network latency
  • Full Data Sovereignty: Keeping sensitive data entirely in-house

Advantages​

  • Full control over hardware and software
  • Data never leaves your premises
  • No recurring cloud subscription costs
  • No dependency on internet connectivity
  • Easier compliance with strict data regulations

Disadvantages​

  • High upfront capital costs (hardware, facilities, cooling)
  • Requires dedicated IT staff for maintenance
  • Scaling requires purchasing and installing new hardware
  • You are responsible for all updates, patches, and security
  • Hardware can become outdated

Infrastructure as a Service (IaaS)​

Definition​

IaaS only provides virtualized computing resources over the internet. It offers the fundamental building blocks you need for building your own cloud IT infrastructure.

What You Get​

  • Virtual machines
  • Storage
  • Networks
  • Operating systems

Responsibilities​

You manage:

  • Operating systems
  • Applications
  • Data
  • Runtime environments
  • Middleware

Provider manages:

  • Physical servers
  • Storage hardware
  • Networking equipment
  • Virtualization layer

Use Cases​

  • Testing and Development: Quickly spin up/down test environments
  • Website Hosting: Host websites with full control over the infrastructure
  • Storage and Backup: Large-scale data storage solutions
  • High-Performance Computing: Computationally intensive workloads

Advantages​

  • Complete control over infrastructure
  • Pay-as-you-go pricing model
  • Highly scalable
  • No time-consuming physical hardware maintenance

Disadvantages​

  • Requires technical expertise
  • You manage security patches and updates all by yourself
  • More management overhead than PaaS/SaaS

Examples​

  • Amazon Web Services (AWS) EC2
  • Microsoft Azure Virtual Machines
  • Google Compute Engine
  • Hetzner

Platform as a Service (PaaS)​

Definition​

PaaS provides a platform allowing customers to develop, run, and manage applications without dealing with the infrastructure.

What You Get​

  • Ready-to-use runtime environments (Node.js, Python, Java, PHP, ...)
  • Managed databases (PostgreSQL, MySQL, MongoDB, Redis)
  • Automatic deployment (push code via Git => automatic builds)
  • Built-in scaling (your app scales automatically based on traffic)
  • Development tools (logging, monitoring, debugging)

Responsibilities​

You manage:

  • Applications
  • Data

Provider manages:

  • Runtime environment
  • Middleware
  • Operating systems
  • Virtualization
  • Servers, storage, networking

Use Cases​

  • Application Development: Build apps without infrastructure concerns
  • API Development and Management: Create and host APIs
  • Microservices Architecture: Deploy containerized applications

Advantages​

  • Faster development and deployment
  • Built-in scalability
  • Reduced management complexity
  • Focus on code, not infrastructure
  • Integrated development tools

Disadvantages​

  • Less control than IaaS
  • Potential vendor lock-in
  • May not support all programming languages/frameworks
  • Limited customization options

Examples​

  • Heroku
  • Google App Engine
  • Microsoft Azure App Service
  • Red Hat OpenShift
  • AWS Elastic Beanstalk
  • Vercel, Netlify

Software as a Service (SaaS)​

Definition​

SaaS delivers fully functional applications over the internet. Users access software through a web browser without installation or maintenance.

What You Get​

  • Ready-to-use applications
  • Automatic updates
  • Accessible from any device with internet
  • Multi-tenant architecture

Responsibilities​

You manage:

  • User configuration
  • Data input
  • Access permissions

Provider manages:

  • Everything else (application, data, runtime, middleware, OS, infrastructure)

Use Cases​

  • Email and Communication: Business email, messaging
  • Customer Relationship Management (CRM)
  • Collaboration Tools: Document sharing, project management
  • Office Productivity: Word processing, spreadsheets, presentations
  • Human Resources: Payroll, recruiting, employee management

Advantages​

  • No installation or maintenance required
  • Accessible anywhere with internet
  • Automatic updates
  • Lower upfront costs
  • Easy to use and scale

Disadvantages​

  • No control over infrastructure, fully dependant on the operating company
  • Limited customization
  • Data security concerns (data stored externally in the cloud)
  • Subscription costs can add up
  • Dependent on internet connectivity

Examples​

  • Google Workspace (Gmail, Google Docs, Drive)
  • Microsoft 365 (Outlook, Word, Excel, Teams)
  • ADITO (CRM)
  • Slack (Team communication)
  • Dropbox (File storage)
  • Zoom (Video conferencing)

The Pizza Analogy​

A popular analogy compares cloud service models to ordering pizza:

  • On-Premises: You make pizza at home (you manage everything)
  • IaaS: You buy pizza dough and toppings, bake it yourself (infrastructure provided)
  • PaaS: You order pizza for delivery (platform provided, you choose toppings)
  • SaaS: You eat at a pizza restaurant (complete service provided)

Additional Service Models​

Beyond the core three, there are specialized service models:

Function as a Service (FaaS) / Serverless​

  • Run code without managing servers
  • Examples: AWS Lambda, Azure Functions, Google Cloud Functions
  • Pay only for execution time

Database as a Service (DBaaS)​

  • Managed database solutions
  • Examples: Amazon RDS, Azure SQL Database, MongoDB Atlas

Container as a Service (CaaS)​

  • Container orchestration platforms
  • Examples: Amazon ECS, Google Kubernetes Engine, Azure Kubernetes Service

Desktop as a Service (DaaS)​

  • Virtual desktops delivered via the cloud
  • Examples: Amazon WorkSpaces, Azure Virtual Desktop, Citrix DaaS

Backend as a Service (BaaS)​

  • Manages the backend while you take care of the frontend
  • Examples: Supabase, Firebase