In this blog post, we will explore the concept of canary deployments and see how we can apply them to serverless JavaScript applications. Canary deployments allow us to roll out new features or updates gradually to a subset of users, minimizing the risk of introducing bugs or performance issues.
What are canary deployments?
Canary deployments are a deployment strategy where a new version of an application is gradually rolled out to a small subset of users, while the majority of users still use the previous version. This small group of users is often referred to as the “canary group”. By monitoring the behavior and performance of the canary group, we can determine if the new version is stable and performant before rolling it out to all users.
Why use canary deployments for serverless JavaScript applications?
Serverless JavaScript applications, which are typically composed of functions that run in response to events, can benefit from canary deployments in several ways:
-
Reduced impact of potential issues: By rolling out updates to a small subset of users first, any potential issues or bugs can be solved before they affect the entire user base. This approach avoids downtime or disruptions for all users.
-
Performance and scalability testing: Canary deployments allow us to measure the performance and scalability of the new version under real-world conditions. This helps identify any bottlenecks or problems that may not be evident in testing environments.
Implementing canary deployments
To implement canary deployments for serverless JavaScript applications, we can leverage the deployment capabilities provided by cloud platforms like AWS Lambda or Azure Functions. Here is a step-by-step guide:
-
Create duplicate functions: Duplicate the functions or services you want to deploy as a canary version. These functions should be identical to the existing ones but may contain new features or updates.
-
Configure routing or event triggers: Set up routing or event triggers to route a small percentage of incoming requests or events to the canary functions. This can be done using platform-specific features like AWS Lambda aliases or Azure Functions deployment slots.
-
Monitor canary performance: Monitor the performance, latency, and error rates of the canary functions using appropriate monitoring tools. Compare these metrics with the existing functions to evaluate the stability and performance of the canary version.
-
Gradually increase traffic: If the canary version performs well and meets the desired criteria, gradually increase the percentage of traffic routed to the canary functions. Monitor the impact on performance and user experience at each stage.
-
Rollback if necessary: If issues or performance degradation are detected during the canary deployment, rollback to the previous version by reducing the traffic to the canary functions or disabling them altogether.
Conclusion
Canary deployments provide a controlled and risk-mitigated approach to deploying updates to serverless JavaScript applications. By gradually rolling out new versions to a subset of users and monitoring their performance, we can ensure the stability and scalability of our applications. With the deployment capabilities offered by cloud platforms, implementing canary deployments for serverless JavaScript applications becomes easier and more efficient.
References: