Launch Template

💡 Definition

A Launch Template contains the configuration information to launch an EC2 instance. It serves as a blueprint for creating instances, specifying details like the AMI, instance type, key pair, security groups, and user data.

🔑 Key Concepts

• Blueprint: Defines what to launch.
• Versioning: Supports versioning, so you can have multiple versions of a template (e.g., v1 uses t2.micro, v2 uses t3.micro) and easily roll back or upgrade.
• Reusable: Can be used to launch individual EC2 instances or by an Auto Scaling Group.
• User Data: You can include scripts to run upon instance startup.

⚙️ How it Works

1. Create: Define the parameters in the EC2 console.
2. Version: Create new versions when you need to change the configuration.
3. Launch: Select the template (and version) when launching an instance or configuring an ASG.

🎯 Use Cases

• Auto Scaling: The standard way to define the configuration for instances launched by an ASG.
• Standardization: Ensuring all developers launch instances with the same approved configuration.

💰 Pricing Model

• Free: There is no charge for creating or storing Launch Templates. You pay for the resources (EC2 instances) launched from them.

📝 Exam Tips (CLF-C02)

• Replaces Launch Configurations (older, deprecated feature).
• Supports versioning (Launch Configurations do not).
• Used by Auto Scaling Groups.

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See Also: * Auto Scaling * EC2 * AMI