HashiCorp Packer automates the creation of machine images, coming out of the box with support to build images for Amazon EC2, CloudStack, DigitalOcean, Docker, Google Compute Engine, Microsoft Azure, QEMU, VirtualBox, and VMware.
There are lot of tools in market which does the job for Image creation but all of them are not complete Machine/Image as a code. All other alternatives can create Image partially.
We use packer to generate new machine images for multiple platforms on every change to our Configuration Management tools like Chef/Puppet/Ansible It's act single tool for Image building for Multi-provider like AWS/Azure/GCP Helps to achieve Dev/Prod Parity Packer itself doesn't have a state like Terraform. You can't do packer output AMI ID. If you have a scenario where you want to maintain the state for images it would be tough to manage via Packer.
There are lot of tools in market which does the job for Image creation but all of them are not complete Machine/Image as a code. All other alternatives can create Image partially. Main reason for selecting Packer are Packer is lightweight, portable, and command-line driven Packer helps keep development, staging, and production as similar as possible. Packer automates the creation of any type of machine image Multi-provider portability is the feature to die for