Amazon Machine Images (AMIs) in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an Amazon Machine Image (AMI)?

An AMI is a template that contains the information needed to launch a virtual server (EC2 instance) in AWS. It includes the operating system, application server, and applications.

beginner

How does an AMI help in launching EC2 instances?

An AMI provides the base configuration for an EC2 instance, so when you launch an instance, it uses the AMI to know what software and settings to start with.

intermediate

Can you modify an AMI after it is created?

No, AMIs are immutable. To change the configuration, you launch an instance from the AMI, make changes, and then create a new AMI from that instance.

beginner

What are the main types of AMIs?

There are three main types: 1) AWS provided AMIs, 2) Marketplace AMIs from third parties, and 3) Custom AMIs created by users.

beginner

Why is it important to choose the right AMI when launching an EC2 instance?

Choosing the right AMI ensures your instance has the correct operating system, software, and security settings, which saves time and avoids configuration errors.

What does an AMI include when launching an EC2 instance?

A Only the application data

B Only the operating system

C Operating system, application server, and applications

D Network settings only

An AMI includes the operating system, application server, and applications needed to launch an EC2 instance.

Can you directly edit an existing AMI?

A Only if the AMI is from Marketplace

B Yes, AMIs are editable anytime

C Only if the AMI is AWS provided

D No, you must create a new AMI from an instance

AMIs are immutable; to change them, you create a new AMI from a modified instance.

Which type of AMI is created by users from their own instances?

A Custom AMIs

B Marketplace AMIs

C Public AMIs

D AWS provided AMIs

Custom AMIs are created by users from their own configured instances.

Why should you select the correct AMI before launching an EC2 instance?

A To reduce network traffic

B To ensure the instance has the right software and settings

C To increase storage size automatically

D To avoid paying for the instance

Selecting the correct AMI ensures the instance starts with the needed software and configuration.

What is the main purpose of an AMI in AWS?

A To provide a launch template for EC2 instances

B To manage user permissions

C To store data backups

D To monitor network traffic

An AMI acts as a template to launch EC2 instances with predefined settings.

Explain what an Amazon Machine Image (AMI) is and why it is important in AWS.

Think of AMI as a recipe for baking a cake, where the cake is your EC2 instance.

Describe the process to update the software on an AMI.

You cannot change the recipe directly; you bake a new cake with changes and save that as a new recipe.

Practice

1. What is the main purpose of an Amazon Machine Image (AMI)?

easy

A. To monitor server performance

B. To store user data in the cloud

C. To save a server setup so it can be reused later

D. To manage network traffic

Solution

1. Step 1: Understand what an AMI represents

   An AMI is a snapshot of a server's setup including its software and settings.

2. Step 2: Identify the main use of AMIs

   AMIs allow you to reuse this saved setup to launch new servers quickly.

3. Final Answer:

   To save a server setup so it can be reused later -> Option C

4. Quick Check:

   AMI = reusable server setup [OK]

Hint: AMI saves server setup for reuse [OK]

Common Mistakes:

• Confusing AMI with data storage
• Thinking AMI monitors performance
• Assuming AMI manages network

2. Which AWS CLI command correctly creates an AMI from a running instance with ID i-1234567890abcdef0?

easy

A. aws ec2 start-image --instance i-1234567890abcdef0 --name MyServerImage

B. aws ec2 launch-image --instance-id i-1234567890abcdef0 --name MyServerImage

C. aws ec2 make-ami --id i-1234567890abcdef0 --image-name MyServerImage

D. aws ec2 create-image --instance-id i-1234567890abcdef0 --name MyServerImage

Solution

1. Step 1: Identify the correct AWS CLI command for creating an AMI

   The correct command is aws ec2 create-image with the instance ID and a name.

2. Step 2: Match the command syntax with the options

   aws ec2 create-image --instance-id i-1234567890abcdef0 --name MyServerImage uses the correct command and parameters.

3. Final Answer:

   aws ec2 create-image --instance-id i-1234567890abcdef0 --name MyServerImage -> Option D

4. Quick Check:

   create-image + instance-id = create AMI [OK]

Hint: Use 'create-image' with instance ID to make AMI [OK]

Common Mistakes:

• Using wrong command like start-image or launch-image
• Mixing up parameter names
• Omitting instance ID

3. You run this AWS CLI command:
aws ec2 create-image --instance-id i-0abc123def456 --name TestImage
What will be the immediate result?

medium

A. An AMI creation request is started; image becomes available after processing

B. The instance is stopped and then an AMI is created

C. A new AMI is created and available instantly

D. The command fails because instance ID is invalid

Solution

1. Step 1: Understand the behavior of create-image command

   The command starts the AMI creation process but the image is not instantly ready.

2. Step 2: Identify the correct immediate result

   The AMI creation runs in background; the image becomes available after some time.

3. Final Answer:

   An AMI creation request is started; image becomes available after processing -> Option A

4. Quick Check:

   AMI creation is asynchronous [OK]

Hint: AMI creation takes time; not instant [OK]

Common Mistakes:

• Assuming AMI is ready immediately
• Thinking instance stops automatically
• Believing command fails without error

4. You tried to create an AMI with this command:
aws ec2 create-image --instance i-0abc123def456 --name MyImage
But it failed. What is the error?

medium

A. Instance ID format is incorrect

B. Missing required parameter --instance-id

C. AMI name is invalid

D. You cannot create AMI from a running instance

Solution

1. Step 1: Check the command parameters

   The command uses --instance instead of the required --instance-id parameter.

2. Step 2: Identify the cause of failure

   The AWS CLI expects --instance-id to specify the instance; missing this causes failure.

3. Final Answer:

   Missing required parameter --instance-id -> Option B

4. Quick Check:

   Use --instance-id to specify instance [OK]

Hint: Use --instance-id, not --instance [OK]

Common Mistakes:

• Using wrong parameter name
• Assuming instance ID format error
• Thinking AMI can't be made from running instance

5. You want to launch multiple identical servers quickly using an AMI. Which steps should you follow?

hard

A. Create an AMI from a configured instance, then launch new instances using that AMI

B. Launch new instances, then manually configure each one separately

C. Create snapshots of volumes, then attach them to new instances

D. Use AWS Lambda to copy instance settings to new servers

Solution

1. Step 1: Understand how to reuse server setups

   Creating an AMI from a configured instance saves its setup for reuse.

2. Step 2: Use the AMI to launch new instances

   Launching new servers from the AMI ensures they have the same software and settings quickly.

3. Final Answer:

   Create an AMI from a configured instance, then launch new instances using that AMI -> Option A

4. Quick Check:

   AMI enables fast identical server launches [OK]

Hint: Create AMI first, then launch servers from it [OK]

Common Mistakes:

• Configuring each server manually
• Using snapshots instead of AMIs for full setup
• Thinking AWS Lambda copies server setups