DevOps
Intermediate
What is Immutable Deployment?
A deployment strategy where new versions replace existing instances entirely rather than updating them in place.
Immutable deployments create entirely new server instances or containers for each release rather than modifying running ones. The old version continues serving traffic until the new version is verified healthy, then traffic switches. This eliminates configuration drift (where servers diverge over time), ensures reproducibility, and makes rollbacks trivial — just route traffic back to the previous version. Technologies like containerization, machine images (AMIs), and Infrastructure as Code enable immutable deployments. The approach aligns with the cattle not pets philosophy of treating servers as disposable and interchangeable.
