OpenStack Heat vs Terraform

OpenStack Heat is a free, open-source orchestration service for composite applications in OpenStack. Declarative templates describe infrastructure and relationships in human-readable files that can be version-controlled. Heat can create instances, floating IPs, volumes, security groups, and users, while supporting instance high availability, autoscaling, and nested stacks. It runs HOT templates written in YAML and also accepts AWS CloudFormation templates. Templates can integrate with Puppet and Ansible, and operators can extend capabilities with plugins. The service exposes an OpenStack-native REST API and a CloudFormation-compatible Query API. Access is available through a command-line interface, RESTful queries, and the OpenStack dashboard. Heat runs on Linux as a self-hosted service and is provided under the Apache 2.0 license. Installation assumes an existing OpenStack environment with Compute, Image Service, and Identity, with guidance covering Red Hat Enterprise Linux, CentOS, Ubuntu, and Debian.

Terraform is an infrastructure-as-code tool for defining, provisioning, and managing cloud and on-premises resources through human-readable configuration files. Its core process is to write a configuration, review an execution plan, then apply approved changes. Providers connect Terraform to services through APIs, and the Terraform Registry lists providers for AWS, Azure, Google Cloud, Kubernetes, GitHub, and Splunk. Modules package reusable infrastructure configurations that users can find or publish in the Registry. The free Community Edition is a downloadable command-line tool. HCP Terraform adds remote execution, repository connections to GitHub, GitLab, and Bitbucket that can trigger plans after changes, and an API. It stores state remotely with encryption at rest and offers workspaces, single sign-on, and role-based access controls. HCP Terraform and Terraform Enterprise support Sentinel policies. HashiCorp cautions that policy-as-code is a guardrail, not a security boundary, and trusted providers and modules matter because they can access workspace variables and state. Downloads are available for Windows, macOS, and Linux.