immutable infrastructure

Definitions

1. An infrastructure management approach where servers are never modified after deployment — any change requires building a new server image and replacing the old one entirely. This eliminates configuration drift, makes deployments reproducible, and simplifies rollbacks (just redeploy the previous image). The opposite of manually SSHing into servers and running apt-get upgrade.

   In plain English: An approach where servers are never updated in place — instead, you build a fresh new one and throw the old one away, so every server is guaranteed identical.

   Example: We treat EC2 instances as cattle, not pets — if anything goes wrong, we terminate and replace them from the last known-good AMI. That's immutable infrastructure.

Related Terms

• Docker
• Terraform
• Config as Code
• infrastructure as code
• configuration drift
• Process Manager
• Staging Environment
• Static Binary
• Terraform Provider
• Cloud Container