Which AWS service allows for infrastructure as code practices?

AWS CloudFormation is the service designed to enable infrastructure as code practices, allowing users to define their cloud resources in a template format. With CloudFormation, you can create and manage AWS resources using code, ensuring that your infrastructure is easily reproducible and manageable through version control systems. By writing templates in JSON or YAML, you can automate the provisioning of infrastructure, making it more efficient and reducing the potential for human error.

This service also provides the ability to manage the complete lifecycle of these resources. You can create, update, and delete stacks of resources in a controlled manner, helping to maintain a consistent infrastructure environment. The declarative nature of CloudFormation means you simply define what resources you want, and the service takes care of the provisioning and configuration necessary to achieve that state.

In contrast, the other services mentioned do not inherently support infrastructure as code practices. AWS Lambda is primarily a serverless compute service for running code in response to events. AWS S3 is a storage service for object storage. AWS Direct Connect allows for dedicated network connections from your premises to AWS, facilitating network connectivity rather than infrastructure setup. Thus, CloudFormation stands out as the clear choice for implementing infrastructure as code within the AWS ecosystem.