istio.io/_glossary/service-version.md

title	type
Service Version	markdown

In a continuous deployment scenario, for a given service, there can be multiple sets of instances running potentially different variants of the application binary or config. These variants are not necessarily different API versions. They could be iterative changes to the same service, deployed in different environments (prod, staging, dev, etc.). Common scenarios where this occurs include A/B testing, canary rollouts, etc. The choice of a particular version can be decided based on various criteria (headers, url, etc.) and/or by weights assigned to each version. Each service has a default version consisting of all its instances.