Amazon Machine Images (AMIs) in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

What happens when you deregister an AMI?

You have an AMI registered in your AWS account. You decide to deregister it. What is the immediate effect on instances launched from this AMI?

A Existing instances launched from the AMI continue running normally, but you cannot launch new instances from it.

B All existing instances launched from the AMI are terminated immediately.

C The AMI is deleted and all snapshots associated with it are also deleted immediately.

D You can still launch new instances from the AMI for 24 hours after deregistration.

💡 Hint

Think about what deregistering an AMI means for existing and new instances.

Deregistering an AMI prevents new instances from being launched using that AMI. However, existing instances continue to run unaffected because they are already launched.

❓ Architecture

intermediate

Choosing AMI for a multi-region deployment

You want to deploy an application in two AWS regions. You have a custom AMI in region A. What is the best way to use this AMI in region B?

A Launch instances in region B using the AMI ID from region A directly.

B Create a new AMI in region B by launching an instance and creating an AMI from it.

C Copy the AMI from region A to region B before launching instances.

D Use the public AMI with the same name in region B.

💡 Hint

AMIs are region-specific. Think about how to make an AMI available in another region.

AMIs are specific to a region. To use a custom AMI in another region, you must copy it to that region first. You cannot launch instances in one region using an AMI ID from another region.

❓ security

advanced

Securing AMI sharing with other AWS accounts

You want to share a private AMI with another AWS account securely. Which option ensures the AMI is shared but the underlying snapshots remain private?

A Export the AMI and send it as a file to the other account.

B Modify the AMI launch permissions to include the other account, but do not modify snapshot permissions.

C Create a public AMI so anyone can launch instances from it.

D Share the AMI and also share the snapshots with the other account explicitly.

💡 Hint

Think about what resources are needed to launch an instance from a shared AMI.

Sharing an AMI requires sharing both the AMI launch permissions and the underlying snapshots. Without snapshot permissions, the other account cannot launch instances from the AMI.

✅ Best Practice

advanced

Automating AMI creation with minimal downtime

You want to automate creating updated AMIs of your application servers daily with minimal downtime. Which approach is best?

A Manually create AMIs from instances during off-hours.

B Use AWS Systems Manager Automation to create AMIs from running instances without stopping them.

C Create AMIs only from stopped instances to ensure data consistency.

D Stop the instance, create an AMI, then start the instance again every day.

💡 Hint

Consider how to create AMIs without stopping instances to avoid downtime.

AWS Systems Manager Automation can create AMIs from running instances using snapshots, minimizing downtime. Stopping instances daily causes downtime and is less efficient.

🧠 Conceptual

expert

Understanding AMI lifecycle and snapshot dependencies

You deregister an AMI but keep its snapshots. Later, you create a new AMI using those snapshots. What is the impact on instance launch and storage costs?

A You can launch instances from the new AMI, and storage costs continue for snapshots until deleted.

B You cannot launch instances from the new AMI because snapshots are orphaned.

C Instances launched from the new AMI will be free of storage costs for snapshots.

D Storage costs stop immediately after deregistering the original AMI.

💡 Hint

Think about how snapshots relate to AMIs and billing.

Deregistering an AMI does not delete snapshots. You can create new AMIs from existing snapshots. Storage costs for snapshots continue until snapshots are deleted.

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