Instance metadata and user data in AWS - Mini Project: Build & Apply

AWS EC2 Instance Metadata and User Data

📖 Scenario: You are setting up a new AWS EC2 instance for a small web application. You want to configure the instance so it can access its own metadata and run a simple startup script automatically when it launches.

🎯 Goal: Build an AWS EC2 instance configuration that includes accessing instance metadata and setting user data to run a startup script.

📋 What You'll Learn

Create a variable with the instance metadata URL

Create a variable with a simple user data script

Write code to fetch instance metadata using the metadata URL

Add the user data script to the EC2 instance configuration

💡 Why This Matters

🌍 Real World

Accessing instance metadata and using user data scripts are common tasks when configuring cloud servers to automate setup and retrieve instance details.

💼 Career

Cloud engineers and DevOps professionals often write user data scripts and query instance metadata to automate server configuration and monitoring.

1

Create the instance metadata URL variable

Create a variable called metadata_url and set it to the exact string "http://169.254.169.254/latest/meta-data/".

AWS

# Create a variable called metadata_url with the instance metadata URL
# Your code here

Need a hint?

The instance metadata service is accessed via a special IP address. Use that exact URL.

2

Create the user data script variable

Create a variable called user_data_script and set it to the exact multi-line string that contains a bash script starting with #!/bin/bash and includes the line echo "Hello from user data" > /var/tmp/user_data_output.txt.

AWS

metadata_url = "http://169.254.169.254/latest/meta-data/"
# Create a variable called user_data_script with the startup bash script
# Your code here

Need a hint?

The user data script runs on instance launch. Use triple quotes for multi-line string.

3

Fetch instance metadata using the metadata URL

Write code to import the requests library and create a variable called instance_id that fetches the instance ID by sending a GET request to metadata_url + 'instance-id' and getting the text response.

AWS

metadata_url = "http://169.254.169.254/latest/meta-data/"
user_data_script = """#!/bin/bash
 echo \"Hello from user data\" > /var/tmp/user_data_output.txt
"""
# Import requests and fetch instance ID from metadata
# Your code here

Need a hint?

Use requests.get() to fetch metadata and .text to get the string.

4

Add the user data script to the EC2 instance configuration

Create a dictionary called ec2_config with a key 'UserData' set to the variable user_data_script.

AWS

import requests

metadata_url = "http://169.254.169.254/latest/meta-data/"
user_data_script = """#!/bin/bash
 echo \"Hello from user data\" > /var/tmp/user_data_output.txt
"""

instance_id = requests.get(metadata_url + 'instance-id').text
# Create ec2_config dictionary with UserData key
# Your code here

Need a hint?

The EC2 configuration dictionary should include the user data script under the 'UserData' key.