Flux

Push a commit, cluster updates itself. Flux is a GitOps tool that makes Git the source of truth for your infrastructure. It watches your Git repos and container registries, detects changes, and reconciles your cluster to match. No CI/CD pipeline needed for deployments. Git IS the pipeline.

Fully free under Apache 2.0. CNCF graduated project. You get Git repository syncing, Kustomize and Helm support, image update automation, multi-tenancy, and notifications (Slack, Teams, webhooks). It runs as a set of controllers inside your Kubernetes cluster.

The catch: Flux is Kubernetes-only. If you're not on Kubernetes, this isn't for you. The learning curve assumes you already understand Kubernetes concepts (CRDs, controllers, namespaces, RBAC). Debugging reconciliation failures requires understanding both Flux's logic AND Kubernetes internals. And compared to Argo CD (the other major GitOps tool), Flux has no built-in UI; you either use the CLI or third-party dashboards like Weave GitOps.