Cloud service models (IaaS, PaaS, SaaS) in AWS - Commands & Configuration

Introduction

Cloud service models help you choose how much control and responsibility you want over your computer resources. They solve the problem of setting up and managing servers, software, and data by offering different levels of service.

When you want to rent virtual machines and manage everything on them yourself.

When you want to deploy your app without worrying about the underlying servers.

When you want to use ready-made software online without installing anything.

When you want to quickly test a new app without buying hardware.

When you want to focus on your app code and leave infrastructure to the cloud provider.

Commands

This command launches a virtual server (EC2 instance) in AWS, showing how Infrastructure as a Service (IaaS) works by giving you control over a virtual machine.

Terminal

aws ec2 run-instances --image-id ami-0c94855ba95c71c99 --count 1 --instance-type t2.micro --key-name my-key --security-group-ids sg-0123456789abcdef0 --subnet-id subnet-0123456789abcdef0

Expected Output

{

    "Instances": [

        {

            "InstanceId": "i-0abcd1234efgh5678",

            "ImageId": "ami-0c94855ba95c71c99",

            "InstanceType": "t2.micro",

            "State": {

                "Code": 0,

                "Name": "pending"

            },

            "SubnetId": "subnet-0123456789abcdef0",

            "SecurityGroups": [

                {

                    "GroupName": "default",

                    "GroupId": "sg-0123456789abcdef0"

                }

            ]

        }

    ]

}

→

--image-id - Specifies the operating system image for the virtual machine.

→

--instance-type - Defines the hardware resources like CPU and memory.

→

--count - Number of instances to launch.

This command creates a platform for your app using AWS Elastic Beanstalk, an example of Platform as a Service (PaaS) where AWS manages servers and you focus on your app.

Terminal

aws elasticbeanstalk create-application --application-name my-app

Expected Output

{

    "Application": {

        "ApplicationName": "my-app",

        "DateCreated": "2024-06-01T12:00:00.000Z",

        "DateUpdated": "2024-06-01T12:00:00.000Z"

    }

}

→

--application-name - Names your app platform.

This command creates a storage bucket in AWS S3, which is often used by SaaS apps to store user data without managing servers.

Terminal

aws s3 mb s3://my-saas-app-storage

Expected Output

make_bucket: my-saas-app-storage

This command lists all your S3 buckets, showing your SaaS storage resources.

Terminal

aws s3 ls

Expected Output

2024-06-01 12:00:00 my-saas-app-storage

Key Concept

If you remember nothing else, remember: IaaS gives you virtual machines to manage, PaaS gives you a ready platform for your app, and SaaS gives you software ready to use online.

Common Mistakes

Trying to manage servers in SaaS instead of using the software as is.

SaaS means the provider handles all infrastructure and software, so managing servers is unnecessary and impossible.

Use SaaS software directly without trying to control the underlying servers.

Using IaaS but expecting the cloud to handle app deployment automatically.

IaaS only provides virtual machines; you must install and manage your app yourself.

Use PaaS if you want the cloud to manage deployment and scaling.

Confusing PaaS with SaaS and trying to customize SaaS software like a platform.

SaaS is ready-made software with limited customization, unlike PaaS which lets you deploy your own apps.

Choose PaaS when you need to deploy custom apps; choose SaaS for ready-to-use software.

Summary

Use 'aws ec2 run-instances' to launch virtual machines in IaaS.

Use 'aws elasticbeanstalk create-application' to create app platforms in PaaS.

Use AWS S3 commands to manage storage often used by SaaS applications.

Practice

1. Which cloud service model lets you rent virtual machines and storage but requires you to manage the operating system and applications 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 characteristics

   IaaS provides virtual machines and storage but leaves OS and app management to the user.

2. Step 2: Compare with other models

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

3. Final Answer:

   Infrastructure as a Service (IaaS) -> Option B

4. Quick Check:

   IaaS = Rent VMs + manage yourself [OK]

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

Common Mistakes:

• Confusing PaaS with IaaS
• Thinking SaaS includes server management
• Mixing FaaS with IaaS

2. Which of the following is the correct description of Platform as a Service (PaaS)?

easy

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

B. You use ready-made software online without installation.

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

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

Solution

1. Step 1: Identify PaaS features

   PaaS provides a platform to develop and run apps without handling server management.

2. Step 2: Eliminate other options

   Installing and managing software on rented virtual machines describes IaaS. Using ready-made software online without installation describes SaaS, and managing physical servers in your own data center is on-premises management.

3. Final Answer:

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

4. Quick Check:

   PaaS = platform for apps, no server management [OK]

Hint: PaaS = build apps, no server hassle [OK]

Common Mistakes:

• Confusing PaaS with SaaS
• Thinking PaaS requires server management
• Mixing on-premises with cloud models

3. You want to use an online email service without installing or managing any software. Which cloud model does this represent?

medium

A. Infrastructure as a Service (IaaS)

B. Platform as a Service (PaaS)

C. Software as a Service (SaaS)

D. Database as a Service (DBaaS)

Solution

1. Step 1: Understand SaaS usage

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

2. Step 2: Match the example

   Online email services like Gmail are classic SaaS examples.

3. Final Answer:

   Software as a Service (SaaS) -> Option C

4. Quick Check:

   SaaS = ready software online [OK]

Hint: SaaS = use software online, no install [OK]

Common Mistakes:

• Choosing IaaS or PaaS for software use
• Confusing DBaaS with SaaS
• Thinking SaaS requires software installation

4. A developer tries to deploy an app on a cloud platform but must manually install the operating system and runtime. Which cloud model is incorrectly used here?

medium

A. Platform as a Service (PaaS)

B. Infrastructure as a Service (IaaS)

C. Software as a Service (SaaS)

D. Network as a Service (NaaS)

Solution

1. Step 1: Understand PaaS expectations

   PaaS should handle OS and runtime installation automatically.

2. Step 2: Identify the error

   Manually installing OS means the platform is acting like IaaS, not PaaS.

3. Final Answer:

   Platform as a Service (PaaS) -> Option A

4. Quick Check:

   PaaS = no manual OS install [OK]

Hint: PaaS hides OS setup; manual means wrong model [OK]

Common Mistakes:

• Assuming manual install fits PaaS
• Confusing IaaS with PaaS
• Ignoring SaaS and NaaS differences

5. A startup wants to quickly launch a web app without managing servers but needs custom code and database control. Which cloud model should they choose and why?

hard

A. PaaS, because it lets them deploy code easily without server management.

B. IaaS, because it offers full control over servers and databases.

C. SaaS, because it provides ready-made apps with no coding needed.

D. On-premises, because cloud models don't allow custom code.

Solution

1. Step 1: Analyze startup needs

   They want no server management but need to run custom code and control databases.

2. Step 2: Match needs to cloud models

   IaaS requires server management, SaaS lacks custom code control, on-premises is not cloud.

3. Step 3: Confirm PaaS fit

   PaaS allows deploying custom code and managing databases without managing servers.

4. Final Answer:

   PaaS, because it lets them deploy code easily without server management. -> Option A

5. Quick Check:

   Custom code + no server management = PaaS [OK]

Hint: Custom code + no servers = PaaS [OK]

Common Mistakes:

• Choosing IaaS despite server management need
• Picking SaaS which lacks custom code control
• Thinking on-premises is cloud