Atlantis Terraform PRs

Automate Terraform plan/apply via PR comments with Atlantis. Generates atlantis.yaml project configs, server-side workflows, custom run steps, policy checks (Conftest), and locking strategies.

This skill covers Atlantis: deploying the server (Helm/Fargate/EC2), per-repo atlantis.yaml with projects, workflows, and autoplan triggers, server-side workflow defaults, custom run steps (tflint, infracost, checkov), policy_check stage with Conftest/OPA, parallel plan/apply, workspace locking, importing existing state, and AWS IAM auth via OIDC. Also covers Terragrunt + Atlantis patterns.

When to use

Use when bringing PR-driven Terraform workflows to a team, gating applies on policy/cost checks, or scaling beyond a single state file.

Examples

Multi-project monorepo

Auto-plan only changed modules

Write an atlantis.yaml for a monorepo with terraform/aws-dev, terraform/aws-prod, and terraform/gcp directories — autoplan only the projects whose files changed, require approval before apply on prod, and run tflint + infracost on every plan

OPA policy gate

Block destructive plans

Add a policy_check workflow to Atlantis using Conftest with an OPA policy that blocks any plan deleting an RDS instance or S3 bucket, and requires two approvers to override