“Launch Templates” in AWS Auto Scaling are configurations that an Auto Scaling group uses to launch EC2 instances. They store the configuration information necessary to launch an instance, which includes the ID of the Amazon Machine Image (AMI), the instance type, a key pair, security groups, and the storage configuration. It helps in setting up new instances quickly and prevent configuration inconsistencies across instances. These templates can also be versioned, allowing updates and roll backs to previous configurations.

What is a Launch Template?

• A Launch Template is like a blueprint that has all the details you need to launch a new EC2 instance (virtual machine) on AWS. It includes things like the machine’s type, storage size, network settings, and more.

Why Use Launch Templates?

• They save time because you don’t have to set up each instance from scratch.
• They ensure consistency, so each instance you launch has the same configuration.
• They support versioning, which lets you update or revert changes easily.

Key Things to Know

1. Version Control: You can save different versions of a Launch Template, so if you make updates, you can always go back to a previous setup.
2. Flexible Configurations: Launch Templates can be set up with advanced options, like mixing instance types or using Spot Instances to save costs.
3. Reusable Across Services: They work well with services like Auto Scaling and CloudFormation, helping you quickly deploy and scale applications.

When to Use Launch Templates

• Auto Scaling: If you want AWS to automatically add or remove instances based on demand, Launch Templates make sure the instances are configured just the way you need.
• Simplified Launching: Use them to launch multiple instances that should all be the same, for example, if you’re setting up several servers with the same software and settings.

Best Practices

• Use Versions: When making changes, create new versions so you can always revert to a previous setup if needed.
• Secure Configurations: Include security groups and IAM roles in the template to keep your instances safe.
• Optimize Costs: Use Spot Instances in your template to reduce costs for applications that don’t need constant uptime.