Packer is a tool that allows users to create machine images for multiple platforms from a single source configuration. It supports cloud providers like AWS, Azure, GCP and OpenStack. The document discusses using Packer to create optimized OS images with tools like cloud-init for fast provisioning and deployment of applications during scale-out operations. It also describes integrating Packer with
![power-assert, mechanism and philosophy](https://cdn-ak-scissors.b.st-hatena.com/image/square/49097c9482863897d258fc5b1859bba949a2dbd2/height=288;version=1;width=512/https%3A%2F%2Fcdn.slidesharecdn.com%2Fss_thumbnails%2Fpower-assert-nodefest-2014-141115024050-conversion-gate01-thumbnail.jpg%3Fwidth%3D640%26height%3D640%26fit%3Dbounds)