Ansible is an open-source automation tool used for configuration management, infrastructure provisioning, and application deployment in AWS environments. It simplifies the automation and management of AWS services through its wide range of modules designed specifically for this purpose. The dynamic inventory feature allows users to automatically pull inventory from external sources like cloud providers. Ansible's simplicity makes it a valuable tool for managing large-scale cloud infrastructures, and its robust capabilities at scale make it an essential part of every Cloud Engineer's toolbelt.