Instance metadata and user data in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is instance metadata in AWS EC2?

Instance metadata is data about your EC2 instance that you can access from within the instance. It includes information like instance ID, public IP, and security groups.

beginner

How do you access instance metadata from an EC2 instance?

You access instance metadata by making an HTTP GET request to the special URL http://169.254.169.254/latest/meta-data/ from inside the instance.

beginner

What is user data in AWS EC2 instances?

User data is a script or commands you provide when launching an EC2 instance. It runs automatically on the first boot to configure the instance.

intermediate

Can instance metadata be modified by the user?

No, instance metadata is read-only and provided by AWS. You cannot change it from inside the instance.

intermediate

Why is it important to secure access to instance metadata?

Because instance metadata can contain sensitive information like IAM role credentials, unauthorized access can lead to security risks.

Where do you retrieve EC2 instance metadata from inside the instance?

A http://169.254.169.254/latest/meta-data/

B http://aws.amazon.com/metadata

C http://instance-data.aws/

D http://localhost/metadata

Instance metadata is accessed via the special IP 169.254.169.254 inside the instance.

What happens to user data scripts after the first boot of an EC2 instance?

A They run every time the instance restarts

B They run only when manually triggered

C They never run automatically

D They run automatically only on the first boot

User data scripts run automatically only during the first boot of the instance.

Which of the following is NOT part of instance metadata?

A User data script

B Public IP address

C Security groups

D Instance ID

User data is separate from instance metadata; it is a script provided at launch.

Why should you restrict access to instance metadata service?

A To reduce AWS costs

B To speed up instance boot time

C To prevent unauthorized access to sensitive data like IAM credentials

D To allow multiple users to share metadata

Instance metadata can contain sensitive info, so restricting access improves security.

How can you provide user data to an EC2 instance?

A By editing the instance metadata URL

B During instance launch via the AWS console or CLI

C By logging into the instance and creating a file

D By attaching an EBS volume

User data is provided at launch time through the AWS console, CLI, or API.

Explain what instance metadata is and how it can be accessed inside an EC2 instance.

Think about the special IP address used inside the instance.

Describe the purpose of user data in EC2 instances and when it runs.

Consider how you automate setup when launching a new server.