Launching an EC2 instance

The lifecycle of an EC2 instance unfolds from the moment of its launch, a critical step that involves detailed configuration to align the instance with specific operational needs. This customization covers computing power, storage options, network configurations, and security settings, ensuring the instance’s optimal fit for its intended role. Post-launch, the instance enters a phase of active management, where users can start, stop, terminate, or restart it based on operational demands. In this topic, we will look at launching an instance, as we prepare it to run our applications.

Selecting the AMI

Your applications will run on an operating system. Your applications must operate on an OS such as Linux, Windows, or MacOS. Since EC2 instances are an Infrastructure as a Service offering, you're responsible for managing this. You will need to select the right operating system (OS), applications, and any associated configuration settings. You will also need to ensure consistency when you launch several instances.

AWS makes this a breeze with Amazon Machine Images (AMIs). AMIs are pre-configured templates used to create virtual machines within the AWS ecosystem. An AMI contains all the necessary information to launch an instance. These templates allow users to launch as many instances as needed, all configured similarly from a single AMI. This ensures consistency and simplifies the setup process for large-scale deployments.

An AMI contains:

• Amazon EBS snapshots or a template for instance-store-backed AMIs, including OS and applications.

• Launch permissions to specify which AWS accounts can launch instances.

• A block device mapping to define attached volumes at launch.

Users can choose from a wide range of AMIs provided by AWS. These include various configurations of Linux, Windows, and other software stacks like LAMP (Linux, Apache, MySQL, PHP) or MEAN (MongoDB, Express.js, AngularJS, Node.js). Users can also create custom AMIs, which is beneficial for organizations that need to tailor their instances with specific software or configurations for compliance and security reasons. Once created, these custom AMIs can be shared with other AWS accounts or made public for broader use.

Imagine we are building a web server that runs NGINX or Apache used to serve our site. Log in to your AWS account, and head over to the EC2 console dashboard. In the EC2 Dashboard, click the “Launch Instance” button to start the instance setup process. Choose any name you like for your web server. For this use case, we would choose a Linux-based AMI such as Amazon Linux, Ubuntu, or Debian for simplicity. Once we've selected an AMI, we need to select an instance type. What is an instance type, you ask? Read on to find out.

Selecting an Instance Type

Workloads vary significantly in their requirements. Different applications require different combinations of hardware resources such as CPU, memory, storage, and network bandwidth. AWS understands this and provides a variety of instance types for various use cases. The instance type of an EC2 instance determines the combination of hardware resources for the physical host that runs your instance.

The following table provides a quick overview of the primary AWS instance types and their most common use cases:

As part of the AWS free tier, you get up to 750 hours per month of t3.micro usage. This instance type offers 2 vCPUs and 1 GiB of memory, and the ability to burst performance above the baseline using CPU Credits. This generous offering is ideal for developers, early-stage startups, and educational purposes, providing a cost-effective way to explore and build on AWS without initial investment.

Now that you know you can launch instances for free on AWS, go on and log in to your AWS account, and head over to the EC2 console dashboard. In the EC2 Dashboard, click the “Launch Instance” button to start the instance setup process. Ensure you select the t3.micro as the instance type.

Setting up a key pair

The next step is setting up a key pair. Key pairs in AWS are used to securely connect to EC2 instances. Each key pair consists of a public key that AWS stores, and a private key file that you store. Together, they allow you to access your instance securely via SSH (Secure Shell) for Linux-based instances, or RDP (Remote Desktop Protocol) for Windows-based instances.

When you launch an EC2 instance, you can select an existing key pair or create a new one. If you create a new key pair, AWS will generate it and provide you with a .pem or .ppk file (private key) to download. It's crucial to download and save this file securely, as AWS does not keep a copy of the private key and you cannot retrieve it if lost. Without the private key, you cannot access the instance.

For security, it's recommended to set the private key file permissions to read-only by you. On Linux and macOS, you can set this using the command chmod 400 your-key-name.pem. When connecting to your instance, you specify the private key in your SSH command with -i your-key-name.pem. For Windows, you decrypt this key pair to obtain the password for the Administrator user. This ensures a secure way to connect to your instance.

Key pairs are region-specific in AWS, meaning a key pair created in one region cannot be used in another. If you operate across multiple regions, you will need to create a key pair in each region. Always handle key pairs with care to avoid unauthorized access to your instances. If a private key is compromised, it's advisable to terminate the associated instance and launch a new one with a new key pair for safety.

You can create a key pair when launching an instance or from the "Network & Security > Key Pairs" section of the EC2 console dashboard. Alternatively, you can use the AWS CLI to create a key pair using the following command:

aws ec2 create-key-pair --key-name <key-pair-name>

The command will output a JSON response containing the private key material. Copy the private key portion into a text file and save it with a .pem or .ppk extension (e.g., myNginxServer.pem).

Setting up network and storage

During the setup of our EC2 instance to host our web server, it’s important to tailor the network and storage settings:

1. Navigate to the network settings tab and click the "Edit" button.

2. Select a Virtual Private Cloud (VPC) that meets your security and regional requirements. For most NGINX servers, the default VPC should suffice. Choose your preferred VPC from the dropdown menu. You can also create your own VPC.

3. Choose a subnet that is geographically close to your primary users to reduce latency. Ensure this subnet is situated in your chosen Availability Zone to enhance performance and reliability.

4. Either create a new security group or modify an existing one. Set rules to allow inbound traffic on port 80 (HTTP), port 443 (HTTPS) for web access, and port 22 (SSH) for secure server management. For additional security, limit SSH access to only known IP addresses.

5. Configure your Elastic Block Store (EBS) volume based on your storage requirements. The default setting is typically 8 GB, adequate for basic web server operations.

These steps ensure that your EC2 instance is optimized for network performance and secured storage configuration, essential for running an efficient and secure web server.

Advanced options

When configuring an EC2 instance, you can utilize several advanced options to optimize performance, enhance security, and manage costs effectively. Two critical features to consider are Instance Profiles and User Data. Instance profiles grant EC2 instances permissions to AWS resources without hard-coding credentials. This is achieved through IAM roles, enhancing security by managing permissions centrally.

User data scripts automate software installations and configurations directly when an EC2 instance launches. This allows for a hands-off setup process, ensuring all instances are configured consistently without manual intervention. User data scripts in Linux instances are commonly used to automate software installation and system configuration. In Windows instances, they allow management tasks like setting up Windows features, running PowerShell scripts, and configuring system settings at launch.

Below is a basic user data script snippet that automates the installation and initial setup of the Apache web server on an Amazon EC2 instance. This example assumes you are using an Amazon Linux 2023 AMI:

#!/bin/bash
# Update the repository information
sudo yum update -y

# Install the Apache web server
sudo yum install -y httpd

# Start the Apache server
sudo systemctl start httpd.service

# Enable Apache to start on boot
sudo systemctl enable httpd.service

# Optional: Create a simple HTML file to verify Apache installation
echo "<html><body><h1>Welcome to Apache on AWS EC2</h1></body></html>" > /var/www/html/index.html

If your security group allows inbound traffic on port 80, the created HTML file can be accessed at http://<instance-public-ip>/index.html in your web browser. This will display the welcome message from the Apache server.

Here's a brief overview of other advanced options available for EC2 instances:

Using CLI commands

To deploy your EC2 instance efficiently, utilize the following command, ensuring to substitute the placeholders with your specific details such as AMI ID, key pair name, and security group ID.

aws ec2 run-instances \
 --image-id ami-1234567890abcdef0 \ # Replace with your Amazon Linux 2023 AMI ID
 --count 1 \
 --instance-type t3.micro \
 --key-name myNginxServer \ # Replace with your key pair name
 --subnet-id subnet-87654321 \ # Replace with your subnet ID
 --security-group-ids sg-12345678 \ # Replace with your security group ID
 --user-data file://your_script.sh

Here's a breakdown of the CLI command:

• aws ec2 run-instances: Triggers the process of launching an EC2 instance;

• --image-id: Specifies the AMI ID. Use the Amazon Linux 2023 AMI ID, or choose another from the AWS Marketplace as needed;

• --count 1: Specifies the number of instances to launch;

• --instance-type t3.micro: Sets the instance type to t3.micro;

• --key-name: Designates the key pair for secure SSH access;

• --subnet-id : ID of the subnet within your chosen VPC. Can be omitted to launch in the default VPC;

• --security-group-ids: Assigns the instance to a security group;

• --user-data: Attaches a user data script that executes automatically when the instance boots.

This command configures and launches your instance with the settings provided.

Conclusion

In this comprehensive guide, we explored the nuanced process of launching and managing an EC2 instance within the AWS ecosystem. From selecting the appropriate Amazon Machine Image (AMI) and instance type to understanding the pivotal roles of key pairs and network settings, each step is crucial for tailoring the instance to meet specific operational demands. The capacity to choose from a wide array of pre-configured AMIs allows for seamless and consistent deployments across various applications, making AWS a robust platform for both burgeoning developers and large-scale enterprises.

Moreover, the discussion highlighted advanced options like Instance Profiles and User Data, which automate and secure EC2 operations, enhancing the overall efficiency and security of the deployment process. The integration of these features with AWS’s flexible management capabilities enables users to efficiently handle instances with tailored configurations for optimal performance and cost management. Whether you’re deploying a simple web server or a complex, resource-intensive application, the tools and strategies outlined here equip you with the knowledge to effectively utilize AWS EC2 instances to their full potential.