Google Research

Canary Analysis Service

Abstract

“Canarying” is a colloquial term originating from bringing a caged canary into a mine to find dangerous gases. John Scott Haldane proposed the idea around 1913.

In this article, canarying is a partial and time-limited deployment of a change in a service, followed by an evaluation of whether the service change is safe. The production change process may then roll forward, roll back, alert a human, or do something else. Effective canarying involves many decisions—for example, how to deploy the partial service change or choose meaningful metrics—and deserves a separate discussion.

Canary Analysis Service (CAS) is a shared centralized service at Google that offers automatic (and often auto-configured) analysis of key metrics during a production change. We use CAS to analyze new versions of binaries, configuration changes, data set changes, and other production changes. CAS evaluates hundreds of thousands of production changes per day.

Learn more about how we do research

We maintain a portfolio of research projects, providing individuals and teams the freedom to emphasize specific types of work