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description: Flagger is a progressive delivery Kubernetes operator
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# Introduction

[Flagger](https://github.com/weaveworks/flagger) is a **Kubernetes** operator that automates the promotion of canary 
deployments using **Istio**, **Linkerd**, **App Mesh**, **NGINX** or **Gloo** routing for traffic shifting and **Prometheus** metrics for canary analysis.
The canary analysis can be extended with webhooks for running system integration/acceptance tests, load tests, or any other custom validation.

Flagger implements a control loop that gradually shifts traffic to the canary while measuring key performance 
indicators like HTTP requests success rate, requests average duration and pods health. 
Based on analysis of the **KPIs** a canary is promoted or aborted, and the analysis result is published to **Slack** or **MS Teams**.

![Flagger overview diagram](https://raw.githubusercontent.com/weaveworks/flagger/master/docs/diagrams/flagger-canary-overview.png)

Flagger can be configured with Kubernetes custom resources and is compatible with 
any CI/CD solutions made for Kubernetes. Since Flagger is declarative and reacts to Kubernetes events, 
it can be used in **GitOps** pipelines together with Weave Flux or JenkinsX.

This project is sponsored by [Weaveworks](https://www.weave.works/)