A team currently manages EC2 Auto Scaling using a Launch Configuration created two years ago. They now want to launch a new instance type and combine On-Demand and Spot purchase options across multiple instance types within the same Auto Scaling group. What should they do?
- Edit the existing Launch Configuration to add the new instance type and mixed purchase options
- Migrate to a Launch Template, which supports versioning and mixed instances policies
- Do nothing, because Launch Configurations already support mixed instances policies
- Create a second, separate Auto Scaling group that uses only Spot Instances
Correct answer: B. Migrate to a Launch Template, which supports versioning and mixed instances policies
Launch Configurations are immutable once created, so they cannot be edited to add settings, which rules out the first option outright, and they also lack support for several newer Auto Scaling capabilities, including mixed instances policies that combine On-Demand and Spot purchase options across multiple instance types in a single group. Launch Templates are the modern replacement: they support versioning so changes can be iterated on safely, expose the full range of current EC2 launch parameters, and are required to configure a mixed instances policy, making the second option correct. The third option is simply factually wrong, since Launch Configurations were never extended to support mixed instances policies. The fourth option could technically work operationally, but it abandons the stated goal of keeping this within one Auto Scaling group and needlessly duplicates and fragments the infrastructure instead of solving the underlying limitation.
Source: AWS documentation: Amazon EC2 Auto Scaling — launch templates versus launch configurations