Flagger

Flagger is an operator for Kubernetes that rolls out new versions of an app gradually. It watches metrics during the rollout and reverts the change on its own when something goes wrong.

Flagger shifts a small share of traffic to a new version and checks metrics such as request success rate and latency. If the checks pass, it moves more traffic over. If they fail, it sends traffic back to the old version. It supports canary, A/B testing and blue/green patterns, and it works with several ingress controllers and service meshes.

• Canary releases with gradual traffic shifting
• Blue/green traffic switching and mirroring
• A/B testing by HTTP headers or cookies
• Custom metric checks and webhook tests
• Automatic rollback when checks fail

Platform and DevOps teams that run Kubernetes and want safer production releases. It suits teams that already use a service mesh or ingress controller that Flagger supports.

Flagger is open source under the Apache 2.0 licence and is part of the Flux project family. It runs inside your own cluster, so the tool itself has no fee. You need a supported traffic router, such as a service mesh or ingress controller, already in place before it can shift traffic.