Comparison
Configuration driftvsImmutable infrastructure
Configuration drift
one instance behaves differently from the others and nobody can say what was changed on it by hand eight months ago.
Divergence between the intended configuration and what is actually running, accumulated through manual fixes. It produces failures that reproduce on one node only and cannot be tested for. Infrastructure as code plus immutable deploys remove it by making the running state disposable.
Full entry →Immutable infrastructure
you never patch a running server; you build a new image and replace the instance entirely.
Treating deployed artefacts as read-only and replacing rather than modifying them. It eliminates configuration drift and makes environments reproducible from source. It requires the build and replace cycle to be fast, and it makes stateful nodes the special case that needs a real plan.
Full entry →