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Blue-Green Deployments

2 posts · Jun 2023 – Apr 2024

What this trail covers

Vercel's platform supports advanced deployment strategies like blue-green deployments by leveraging immutable deployments, serverless architecture, Skew Protection, Edge Config, and Middleware. This allows for safe, cost-efficient rollouts with minimal infrastructure overhead and granular control over traffic allocation and user experience. The platform also enables innovative strategies like multicolor and shadow rollouts. Skew Protection ensures that clients that loaded the form with the old field name talk to servers with the exact same version which respectively know how to handle that field name. This mechanism is enabled by encoding the deployment ID in response HTML for hard navigations, and routing subsequent requests based on that ID.

All Vercel trails
  1. Releasing safe and cost-efficient blue-green deploymentsThis post details how Vercel's platform primitives (Skew Protection, Edge Config, Middleware) and serverless architecture enable cost-efficient and scalable blue-green deployments. It highlights how immutable deployments and the absence of duplicated infrastructure reduce overhead and costs compared to traditional Kubernetes-based approaches. It also introduces multicolor and shadow rollout strategies as extensions of blue-green deployments.
  2. Introducing Skew ProtectionIntroduces Skew Protection, a novel mechanism to eliminate version skew between web clients and servers. This feature ensures that clients that loaded an application with an older version communicate with servers running that same version, preventing errors caused by mismatched deployments. It is enabled by encoding the deployment ID in response HTML for hard navigations and routing subsequent requests based on this ID. The feature is configurable via `next.config.js` for Next.js applications and can be manually implemented for other request types using the `X-Deployment-Id` header. Trade-offs include the risk of downgrade attacks, mitigated by not supporting deployment-binding on browser navigations and limiting to same-origin requests, and the need to consider backend service backward compatibility.