Cloud Service and Deployment Models
The service model decides where the line falls between what the provider manages and what you do. Exam questions almost always test that line rather than the definitions.
Cloud Service and Deployment Models · firsttry.app/cheatsheets/cloud-service-models · original reference written from published exam objectives. Not affiliated with any certification body.
Who manages what
| Layer | On-premises | IaaS | PaaS | SaaS |
|---|---|---|---|---|
| Applications | You | You | You | Provider |
| Data | You | You | You | You |
| Runtime | You | You | Provider | Provider |
| Middleware | You | You | Provider | Provider |
| Operating system | You | You | Provider | Provider |
| Virtualization | You | Provider | Provider | Provider |
| Servers and storage | You | Provider | Provider | Provider |
| Networking and facilities | You | Provider | Provider | Provider |
Examples
| Model | Azure | AWS |
|---|---|---|
| IaaS | Virtual Machines, Virtual Network | EC2, VPC, EBS |
| PaaS | App Service, Azure SQL Database | Elastic Beanstalk, RDS |
| SaaS | Microsoft 365 | Amazon WorkMail |
| Serverless | Azure Functions | Lambda |
| Containers as a service | Azure Container Apps, AKS | ECS, EKS, Fargate |
Deployment models
| Model | What it is | Suits |
|---|---|---|
| Public | Shared infrastructure, provider owned | Most workloads, elastic demand |
| Private | Dedicated to one organization | Regulatory or latency constraints |
| Hybrid | Public and private connected | Migration, burst capacity, data residency |
| Community | Shared by organizations with common requirements | Sector consortia, government |
| Multicloud | More than one public provider | Avoiding lock-in, using the best of each |
Cloud economics
| Term | Meaning |
|---|---|
| CapEx | Buy the asset up front. On-premises |
| OpEx | Pay as you consume. Cloud |
| Elasticity | Scale with demand, automatically and both ways |
| Scalability | Ability to grow. Vertical is bigger, horizontal is more |
| Agility | Time from deciding to having it running |
| Total cost of ownership | Everything, including staff, power and space |
| Consumption-based pricing | Charged for what you use rather than what you reserved |
Try it here
Three verified practice questions on this material. Answer one, and see the official page behind the answer.
Describe cloud concepts
An engineer adds more CPUs and RAM to an existing virtual machine to handle a heavier workload. Which type of scaling is this?
4-1Billing, Pricing, and Support
How much warning does an EC2 Spot Instance get before it is interrupted?
4-1Security Operations
What is the minimum amount of entropy a session identifier should contain to resist brute-force guessing attacks?
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