The deployment was clean. Every server booted with the exact configuration we committed. No drift. No surprises. This is the promise of Git Immutable Infrastructure.
Git Immutable Infrastructure means every environment is built from version-controlled code and never modified in place. When you need changes, you update the code in Git and redeploy from scratch. Old instances are destroyed; new ones are created. There is no manual patching. There is no guessing what is running in production.
This approach eliminates configuration drift. It makes rollbacks fast and predictable. It ties the entire stack to a single commit, making debugging easier and audits trivial. Every change is traceable. Security improves because patched base images can be deployed with zero manual intervention.
You implement Git Immutable Infrastructure by keeping infrastructure definitions in code—Terraform, Pulumi, or similar—and storing them in Git. Builds produce immutable artifacts, like container images or AMIs. Deployments replace infrastructure with these new immutable versions. Testing environments match production exactly, because they come from the same source.