Learn how Deutsche Bahn confidently deploys mission-critical Kafka Streams apps using blue/green deployments.

The customer information department processes real-time data, keeping travellers informed across various channels. Any downtime or delay in our data feeds immediately affects our customers, e.g. frozen displays on train platforms and outdated loudspeaker announcements throughout Germany.

Blue/green deployment is a well-known, established continuous delivery practice. It is widely used to deploy in frontend or "common API backend" applications, commonly supported out of the box by tools (such as Kubernetes) and SaaS platforms.

Applying this strategy to the world of stream processing poses numerous challenges.
Deploying the 'new' inactive environment may require data reprocessing to bootstrap an aggregated state. How can switching between the two environments be realised while preventing loss of events and keeping event duplication to a minimum?

This practical talk shares how our team has solved the architectural, functional, and procedural challenges. Expect a walk-through of the deployment workflow and how it has evolved, from implementations using Jenkins and Gitlab pipelines to our ongoing migration to a Kubernetes-native, GitOps-compatible solution based on Argo Workflows.