Argo Rollouts vs Flagger
Argo Rollouts
argoproj.github.io
Flagger
flagger.appSide by side
| Figure | Argo Rollouts | Flagger |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | — |
| macOS | Yes | — |
| Linux | Yes | — |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Progressive Delivery Software | 9.0 (#1) | 8.2 (#11) |
| Spec score · Rollback Management | 9.0 (#1) | 8.1 (#10) |
| Spec score · Continuous Delivery Software | 8.9 (#2) | 8.0 (#15) |
| Spec score · Kubernetes Deployment Tools | 8.9 (#2) | 8.1 (#11) |
| Deployment strategies | It supports blue-green, canary, and rolling update strategies. | It supports canary releases, A/B testing, and blue/green deployments. |
| Metrics | Metric provider integrations include Prometheus, Wavefront, Kayenta, Web, Kubernetes Jobs, Datadog, New Relic, Graphite, and InfluxDB. | Release analysis can query Prometheus, InfluxDB, Datadog, New Relic, CloudWatch, Stackdriver, or Graphite. |
| Notifications | The Notifications Engine supports configurable triggers and templates, including integrations such as Slack and Microsoft Teams. | It can send deployment and canary result notifications to Slack, Microsoft Teams, Discord, and Rocket. |
| Purpose | Argo Rollouts is a Kubernetes controller and set of CRDs for advanced deployment and progressive delivery. | Flagger automates progressive delivery for applications running on Kubernetes by shifting traffic gradually while measuring metrics and running conformance tests. |
Plans
In their own words
Argo Rollouts
Argo Rollouts is a self-hosted Kubernetes controller for managing how application updates reach users. It supports BlueGreen, Canary and Rolling Update strategies, with weighted traffic shifting through ingress controllers or service meshes. Without a traffic-routing provider, it can adjust ReplicaSet counts instead. Metric integrations let it assess KPIs and automate promotion or rollback, while leaving room for manual judgment. Supported providers include NGINX, AWS ALB, Istio and Traefik for traffic, and Prometheus, Datadog, New Relic, Graphite and InfluxDB for metrics. It can operate independently of Argo CD and respond to Kubernetes manifest changes whether they come from GitOps or traditional CI/CD. Each cluster running Rollout workloads needs its own controller and CRD; a Rollout specification covers one application, not dependencies among applications. Shared-resource or worker-queue applications may be a poor fit, and infrastructure applications are not recommended. Argo Rollouts is free and open source. It runs on Linux, macOS, Windows or self-hosted environments.
Flagger
Flagger is a self-hosted Kubernetes operator that automates progressive delivery for applications running on Kubernetes. It gradually shifts traffic to a new version while checking measures such as HTTP or gRPC request success and latency. Deployment approaches include canary releases, A/B testing, and blue/green deployments, routed through an ingress controller or a service mesh compatible with the Kubernetes Gateway API. Built-in checks cover HTTP request success rate and duration; teams can add custom metrics and webhooks for acceptance tests, load tests, or other validation. Release analysis can query systems including Prometheus, Datadog, CloudWatch, New Relic, Graphite, Dynatrace, InfluxDB, and Google Cloud Monitoring. If SLO analysis detects a performance drop, Flagger rolls back the release automatically. Manual controls allow approval, pausing, or resuming deployments, and notifications can go to Slack, Microsoft Teams, Discord, or Rocket. It is configured through Kubernetes custom resources, works with Kubernetes-compatible CI/CD solutions, and can be used with Flux for GitOps canary pipelines. Flagger is Apache 2.0 licensed and free.