Launch Template
(Preferred over the older Launch Configuration)
Defines the instance configuration for the ASG, including:
- AMI ID and instance type
- EC2 User Data script for bootstrapping
- EBS volume definitions
- Security Groups for networking rules
- SSH key pair for access
- IAM Role for instance permissions
- Network and subnet placement details
- Load Balancer or Target Group association
Additional ASG Attributes
- Min size – Minimum number of instances to keep running
- Max size – Maximum number of instances allowed
- Desired capacity – Initial or target number of instances
- Scaling policies – Rules that trigger scale in/out actions
Additional Notes:
When you create a Launch Template, the default value for the instance tenancy is shared and the instance tenancy is controlled by the tenancy attribute of the VPC. If you set the Launch Template Tenancy to shared (default) and the VPC Tenancy is set to dedicated, then the instances have dedicated tenancy. If you set the Launch Template Tenancy to dedicated and the VPC Tenancy is set to default, then again the instances have dedicated tenancy.
Amazon EC2 provides three options for the tenancy of your EC2 instances:
Shared (Shared) – Multiple AWS accounts may share the same physical hardware. This is the default tenancy option when launching an instance.
Dedicated instances (Dedicated) – Your instance runs on single-tenant hardware. No other AWS customer shares the same physical server.
Dedicated Hosts (Dedicated host) – The instance runs on a physical server that is dedicated to your use. Using Dedicated Hosts makes it easier to bring your own licenses (BYOL) that have dedicated hardware requirements to EC2 and meet compliance use cases. If you choose this option, you must provide a host resource group for Tenancy host resource group.