Cloud Service Models (XaaS)

Ref: https://learn.cantrill.io/courses/2022818/lectures/45718075

Infra Stack (or App Stack)

Infrastructure layers when deploying a software application:
1. Application
2. Data → data store, DB…
3. Runtime Environment (RTE) → code libraries…
4. Container → Docker, K8s…
5. Operating System (OS) → Linux, Windows, MacOS…
6. Virtualization
7. Server → physical computer/machine
8. Infrastructure → server racks, network routers…
9. Facilities → building, electricity, real estate, security staff…
🔧 Unit of consumption = what the customer pays for and consumes
- Everything below the unit of consumption in the Infra Stack is managed by the vendor
- The unit of consumption itself and everything above in the Infra Stack is managed by the customer
- Each service model differs in its unit of consumption
On-premises → Customers pay for everything in the Infra Stack
- 👎 Expensive, lots of admin overhead, has risks
- 👍 Highest ownership → can be very flexible
Data Center (DC) hosted → Customers pay for using facilities (fully or partially), and take care of everything else
- Popular before cloud computing

🔧 Unit of consumption: OS
- Generally, IaaS provides virtual servers/machines (VMs)
Pricing: generally pay-as-you-go
- Pay a fee per second/min/hour of VM use
- No costs when not using the VM
Lose a bit on flexibility, but gain a lot in cost & risk reductions
One of the most popular cloud services
e.g. Amazon Elastic Compute Cloud (EC2)

🔧 Unit of consumption: Runtime Environment (RTE)
Aimed to developers who have an app that they just want to deploy and run, without caring about underlying infrastructure