Cloud Engineer interview question · Most asked
Explain IaaS, PaaS, SaaS and serverless with examples from AWS, Azure and Google Cloud.
Summary
IaaS gives you virtual machines and networks (EC2, Azure VMs, Compute Engine) and you manage the OS upwards. PaaS runs your application on a managed platform (Elastic Beanstalk, App Service, App Engine). Serverless runs functions or containers on demand with scaling handled for you (Lambda, Azure Functions, Cloud Run). SaaS is a finished application (Microsoft 365, Salesforce).
Longer Answer
The trade-off is control versus operational burden: further up the stack you patch and scale less, but configure less. Most organisations mix models: managed databases (PaaS), containers on a managed orchestrator, functions for event glue.
Key Points
- IaaS: you manage OS and up.
- PaaS: you manage the app.
- Serverless: code or containers, scaling handled.
- SaaS: you configure a finished product.
Deep dive: Cloud Computing Tutorial: Cloud Computing Introduction
Explanation
What interviewers look for
Correct mapping across clouds and the control/operations trade-off.
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