What Is Traffic Mirroring?
Traffic mirroring, also called shadowing, duplicates real production requests and forwards the copy to another version of a service while the primary continues to handle the actual response. The mirrored responses are discarded, so users are unaffected. It lets you exercise a new build with realistic load before it serves anyone.
Why it matters
Mirroring is a safe way to validate a new release against production traffic patterns in a deploy pipeline. It catches regressions that synthetic tests miss without risking user-facing errors.
Where this shows up in a real pipeline
A definition is only useful if you can recognise the thing in your own logs. In practice this concept surfaces when a job behaves differently between a local run and a runner, which is where most CI debugging starts.
- Compare a local run against a CI run of the same command before assuming a tool is at fault.
- Runner environments differ in shell, PATH, TTY availability, available memory, and disk. Most CI-only behaviour traces to one of those five.
- Pin tool versions so an environment difference cannot be introduced by an unrelated update.
Frequently asked questions
What is What is traffic Mirroring??
Traffic mirroring, also called shadowing, duplicates real production requests and forwards the copy to another version of a service while the primary continues to handle the actual response. The mirrored responses are discarded, so users are unaffected. It lets you exercise a new build with realistic load before it serves anyone.
Why does What is traffic Mirroring? matter in CI/CD?
Mirroring is a safe way to validate a new release against production traffic patterns in a deploy pipeline. It catches regressions that synthetic tests miss without risking user-facing errors.
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