CONCEPT Cited by 1 source
Configuration drift¶
Definition¶
Configuration drift is the gradual divergence between an instance's actual state and its intended state. It occurs when long-lived instances accumulate manual changes, partial updates, failed configurations, or undocumented modifications over time — making the fleet heterogeneous even when it was deployed identically.
Why it's dangerous¶
- Unreproducible incidents: Bugs manifest on drifted instances but can't be reproduced on fresh ones.
- Deployment failures: Updates assume a consistent starting state; drift breaks that assumption.
- Security exposure: Missed patches, stale agents, or orphaned configurations create exploitable gaps.
- Operational surprise: The fleet becomes unknowable — you can't reason about what's running where.
How immutable infrastructure eliminates it¶
Immutable infrastructure eliminates configuration drift by construction: instances are replaced rather than modified. The instance state is always identical to the image from which it was launched.
Slack's Shipyard architecture explicitly addresses this: by moving from continuously-updated long-lived EC2 instances to immutable AMIs with short lifespans and automated rotation via The Reaper, "infrastructure drift was inevitable" under the old model becomes a solved problem (Source: sources/2026-07-14-slack-shipyard-next-generation-ec2-platform).
Seen in¶
- sources/2026-07-14-slack-shipyard-next-generation-ec2-platform — configuration drift named as one of the key problems the legacy Chef-based model couldn't solve: "infrastructure drift was inevitable."