A company is deploying a third-party unit testing solution that is delivered as an Amazon...

To implement a highly available solution that provides the functionality to use a minimum of three On-Demand instances and three Spot instances when prices are at a certain threshold, defining an Amazon EC2 Auto Scaling group using a launch template is the most suitable solution. This approach minimizes operational overhead by consolidating configuration and management tasks.

Define a Launch Template:

Use the provided AMI in the launch template.

Configure the instance type, key pair, security groups, and other necessary parameters.

Create an Auto Scaling Group:

Use the launch template for the Auto Scaling group.

Specify a desired capacity of three On-Demand instances.

Configure the Auto Scaling group to use mixed instances policies, which allow you to specify a combination of On-Demand and Spot instances.

Set the maximum price for Spot instances in the launch template to ensure that Spot instances are used only when their prices are below the specified threshold.

Configuration Steps:

Open the EC2 console and navigate to "Launch Templates."

Create a new launch template with the necessary configurations.

Navigate to "Auto Scaling Groups" and create a new Auto Scaling group using the launch template.

Configure the desired capacity, minimum capacity, and maximum capacity.

Under "Advanced Options," specify the mixed instances policy and set the maximum price for Spot instances.

Amazon EC2 Auto Scaling Launch Templates

Auto Scaling Mixed Instances Policies