shadow traffic pattern
Send a copy of production traffic to a new code path or new infra, but ignore the response. Lets you measure performance, error rates, and behavior under real load before any user sees it. Catches issues canaries miss because there's no graduated traffic — the new path takes full prod load from day one.
Send a copy of production traffic to a new code path or new infra, but ignore the response. Lets you measure performance, error rates, and behavior under real load before any user sees it. Catches issues canaries miss because there's no graduated traffic — the new path takes full prod load from day one.
symptoms
- canary doesn't catch a regression that hits at 100%
- need to test a rewrite without exposure
causes
- no easy way to compare new vs old at full prod load
fixes
- LB or service mesh mirrors traffic
- compare responses async
- log diffs for analysis
you might say
- shadow it
- mirror traffic
- dark launch