Cloud service models (IaaS, PaaS, SaaS) in Azure - Step-by-Step Execution

Process Flow - Cloud service models (IaaS, PaaS, SaaS)

User Needs Cloud Service

↓

IaaS

↓

More Control

User chooses between IaaS, PaaS, or SaaS based on how much control and management they want over cloud resources.

Execution Sample

Azure

User selects service model:
- IaaS: User manages VMs
- PaaS: User deploys apps
- SaaS: User uses apps directly

Shows how user interaction changes with each cloud service model.

Process Table

Step	User Action	Service Model	User Manages	Cloud Manages	Result
1	Select IaaS	IaaS	OS, VMs, Network	Hardware, Data Center	User controls OS and apps
2	Select PaaS	PaaS	Apps and Data	OS, Middleware, Runtime	User deploys apps without managing OS
3	Select SaaS	SaaS	None	Everything (Apps, OS, Infrastructure)	User uses ready apps
4	End	-	-	-	User chooses model based on control and convenience

💡 User finishes choosing cloud service model based on needs

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
User Control Level	None	High (IaaS)	Medium (PaaS)	Low (SaaS)	Depends on model chosen
Cloud Responsibility	All	Partial (IaaS)	More (PaaS)	All (SaaS)	Depends on model chosen

Key Moments - 3 Insights

Why does IaaS require more user management than SaaS?

Because in IaaS, the user manages the operating system and virtual machines, as shown in execution_table step 1, while in SaaS, the cloud manages everything.

What does PaaS manage for the user compared to IaaS?

PaaS manages the OS, middleware, and runtime, so the user only manages apps and data, as seen in execution_table step 2.

Can a user customize the software in SaaS?

No, SaaS users only use the software as provided without managing or customizing the underlying infrastructure, shown in execution_table step 3.

Visual Quiz - 3 Questions

Look at the execution_table, what does the user manage in PaaS at step 2?

A Operating system and virtual machines

B Applications and data

C Everything including hardware

D Nothing, cloud manages all

💡 Hint

Check the 'User Manages' column at step 2 in execution_table

At which step does the cloud manage everything including apps?

A Step 3

B Step 1

C Step 2

D None of the steps

💡 Hint

Look at 'Cloud Manages' column in execution_table for full management

If a user wants full control over OS and apps, which model should they choose?

A SaaS

B PaaS

C IaaS

D None

💡 Hint

Refer to 'User Manages' in execution_table step 1

Concept Snapshot

Cloud Service Models:
- IaaS: User manages OS, VMs; cloud manages hardware
- PaaS: User manages apps; cloud manages OS and runtime
- SaaS: Cloud manages everything; user just uses apps
Choose based on control vs convenience needs.

Full Transcript

Cloud service models let users pick how much control they want over computing resources. IaaS gives users control over operating systems and virtual machines, while the cloud handles hardware. PaaS lets users deploy apps without managing OS or runtime. SaaS provides ready-to-use applications managed fully by the cloud. Users select a model based on their need for control or ease of use.

Practice

1. Which cloud service model lets you rent virtual machines and manage the operating system yourself?

easy

A. Function as a Service (FaaS)

B. Infrastructure as a Service (IaaS)

C. Software as a Service (SaaS)

D. Platform as a Service (PaaS)

Solution

1. Step 1: Understand IaaS definition

   IaaS provides virtual machines and basic infrastructure, but you manage the OS and software.

2. Step 2: Compare with other models

   PaaS manages the platform, SaaS provides ready software, and FaaS is event-driven code execution.

3. Final Answer:

   Infrastructure as a Service (IaaS) -> Option B

4. Quick Check:

   IaaS = Rent VMs and manage OS [OK]

Hint: IaaS = rent machines, you manage OS and apps [OK]

Common Mistakes:

• Confusing PaaS with IaaS and thinking platform is managed by user
• Choosing SaaS thinking it includes VM management
• Selecting FaaS which is not a main cloud service model here

2. Which of the following is the correct description of PaaS?

easy

A. You install and manage software on rented virtual machines.

B. You manage physical servers in your own data center.

C. You use software online without installing it.

D. You use a platform to build and run apps without managing servers.

Solution

1. Step 1: Recall PaaS meaning

   PaaS provides a ready platform so you can build and run apps without handling server management.

2. Step 2: Eliminate other options

   You install and manage software on rented virtual machines. describes IaaS, C describes SaaS, and D is not cloud service but on-premises.

3. Final Answer:

   You use a platform to build and run apps without managing servers. -> Option D

4. Quick Check:

   PaaS = Platform managed, you build apps [OK]

Hint: PaaS = platform ready, no server management [OK]

Common Mistakes:

• Mixing PaaS with IaaS by thinking you manage servers
• Confusing SaaS with PaaS by thinking you build apps
• Choosing on-premises management as cloud service

3. You want to use Microsoft Azure to run a web app without managing the underlying servers. Which service model will you use?

medium

A. PaaS - Use Azure App Service to deploy your web app

B. IaaS - Create a virtual machine and install web server

C. SaaS - Use Microsoft Word online

D. IaaS - Rent storage only

Solution

1. Step 1: Identify requirement

   The user wants to run a web app without managing servers, so server management should be handled by provider.

2. Step 2: Match service model

   Azure App Service is a PaaS offering that lets you deploy apps without managing infrastructure.

3. Final Answer:

   PaaS - Use Azure App Service to deploy your web app -> Option A

4. Quick Check:

   Run app without servers = PaaS [OK]

Hint: Web app without servers means PaaS like Azure App Service [OK]

Common Mistakes:

• Choosing IaaS and thinking you don't manage servers
• Selecting SaaS which is for ready software, not custom apps
• Confusing storage rental with app hosting

4. A company wants to use cloud software without installing or managing it. They mistakenly choose IaaS and start managing virtual machines. What is the error?

medium

A. They should have chosen SaaS to avoid managing software.

B. IaaS automatically manages software for them.

C. PaaS requires installing software on VMs.

D. IaaS means software is fully managed by provider.

Solution

1. Step 1: Understand SaaS purpose

   SaaS provides ready-to-use software online without installation or management by user.

2. Step 2: Identify mistake with IaaS

   IaaS provides virtual machines but user must install and manage software themselves.

3. Final Answer:

   They should have chosen SaaS to avoid managing software. -> Option A

4. Quick Check:

   Want no software management = SaaS [OK]

Hint: No software management means SaaS, not IaaS [OK]

Common Mistakes:

• Thinking IaaS manages software automatically
• Confusing PaaS with SaaS in software management
• Believing IaaS means fully managed software

5. You want to build a custom business app that needs a database and automatic scaling but you don't want to manage servers or install software. Which Azure service model fits best?

hard

A. IaaS - Rent VMs and install database and app software yourself

B. SaaS - Use a ready-made business app online

C. PaaS - Use Azure SQL Database and Azure App Service

D. On-premises - Manage your own servers and software

Solution

1. Step 1: Analyze requirements

   Needs custom app, database, automatic scaling, no server or software management.

2. Step 2: Match with Azure services

   PaaS offers managed database (Azure SQL Database) and app hosting (Azure App Service) with scaling and no server management.

3. Step 3: Exclude other options

   IaaS requires managing servers and software, SaaS is not custom, on-premises is self-managed.

4. Final Answer:

   PaaS - Use Azure SQL Database and Azure App Service -> Option C

5. Quick Check:

   Custom app + no server management = PaaS [OK]

Hint: Custom app + no servers = PaaS with managed services [OK]

Common Mistakes:

• Choosing IaaS and expecting no server management
• Selecting SaaS expecting custom app building
• Thinking on-premises is cloud service