Blue Green Deployments for Serverless Apps

Blue Green Deployments for Serverless Apps

What are Serverless Applications?

Serverless applications are a type of cloud-based application that uses a serverless computing model. In this model, the cloud provider dynamically allocates resources to the application as needed, rather than the application being deployed on dedicated servers. This means that the application can scale up or down automatically in response to demand, without the need for the developer to provision or manage servers, a concept known as cloud optimization.

Serverless applications have several advantages over traditional applications. They are generally easier to build and maintain, as the developer does not need to worry about managing servers or infrastructure. Because the developer is only charged for the actual usage of the function, serverless applications can also be more cost-effective.

What is Blue-Green Deployment?

Blue-green deployment is a technique for updating a software application in a way that minimizes downtime and reduces the risk of introducing new bugs or other issues. It involves maintaining two separate environments for the application, typically referred to as the “blue” environment and the “green” environment.

In a blue-green deployment, the current version of the application (the “blue” version) is deployed in one environment, while the new version (the “green” version) is deployed in the other environment. Once the green version has been tested and is deemed ready for production, it is switched over to become the active version of the application, while the blue version is decommissioned.

One of the main benefits of blue-green deployment is that it allows for a smooth and seamless transition between versions of the application. Because the blue and green environments are kept separate and are identical in terms of infrastructure and configuration, there is no need to perform complex or risky updates on the live environment. This minimizes the risk of disruptions or errors, and makes it easier to roll back to the previous version if necessary.

How Does Blue-Green Deployment Work?

Blue-green deployment is often used in conjunction with continuous delivery and continuous deployment pipelines, as it allows for quick and reliable updates to the application without downtime or risk to the user experience.

Here is a general overview of how blue-green deployment works:

  1. The development team creates and tests a new version of the application (the “green” version).
  2. The green version is deployed to the green environment, which is identical to the blue environment in terms of infrastructure and configuration.
  3. The green version is thoroughly tested in the green environment to ensure that it is stable and ready for production.
  4. Once the green version has been tested and is deemed ready for production, it is switched over to become the active version of the application (the “blue” version is decommissioned). This is typically done using a load balancer or other routing mechanism that directs traffic to the appropriate environment.
  5. The green version is now live and serving users, while the blue environment is decommissioned or put into standby mode.
  6. When the next update to the application is ready, the process is repeated, with the new version being deployed to the blue environment and tested before being switched over to become the live version.

Why are Blue Green Deployment Important to Serverless Applications?

Blue-green deployment is especially important for serverless applications because serverless architectures can make it more challenging to perform traditional deployments without causing downtime. In serverless architectures, functions are typically triggered by events, such as an HTTP request or a message being published to a message queue. If a new version of a function is deployed while it is processing requests, there is a risk of disrupting the requests being handled by the old version of the function.

Blue-green deployment can help mitigate this risk by allowing the new version of the function to be deployed and tested in a separate environment before traffic is routed to it. This ensures that the new version of the function is fully functional before it starts handling production traffic, minimizing the risk of disrupting the application.

In a serverless environment, blue-green deployment can be used to monitor performance and stability of a serverless application before it is made live. This allows organizations to ensure that the new version is working as intended and does not negatively impact the user experience. 

In addition to reducing the risk of downtime, blue-green deployment can also make it easier to roll back to a previous version of the function if there are any issues with the new version. This can help improve the reliability and stability of serverless applications, which is particularly important for applications that have a high level of traffic or that require high availability.

Best Practices for Using Blue Green Deployment in Serverless Apps

Here are some best practices for using blue-green deployment in serverless applications:

  • Test the new version of the function thoroughly before deploying it to production. This can involve testing the function in a staging environment or using automated testing tools to ensure that it is functioning correctly.
  • Use a load balancer or a reverse proxy to route traffic between the blue and green environments. This allows you to control the amount of traffic being sent to the green environment and gradually ramp it up as you gain confidence in the new version of the function.
  • Monitor the performance of the green environment closely after traffic is routed to it. This can help you identify any issues with the new version of the function and roll back to the blue environment if necessary.
  • Use an automated rollback mechanism to revert to the previous version of the function if there are any issues with the new version. This can involve using a feature flag to toggle between the blue and green environments, or using a tool like AWS CodeDeploy to automate the rollback process.
  • Use a blue-green deployment approach for all deployments to ensure consistent, zero-downtime updates. This can help improve the reliability and availability of your serverless applications.


In conclusion, blue-green deployment is a valuable technique for managing the deployment of serverless applications. By running two identical production environments and swapping traffic between them, organizations can test and validate new versions of their application before they are made live, helping to ensure the stability and performance of their applications. This can be especially useful in a serverless environment, where new versions of an application can be deployed quickly and easily. By using blue-green deployment, organizations can more smoothly and efficiently deploy new versions of their applications, with minimal disruption to their users. 

Author Bio: Gilad David Maayan

Gilad David Maayan is a technology writer who has worked with over 150 technology companies including SAP, Imperva, Samsung NEXT, NetApp and Check Point, producing technical and thought leadership content that elucidates technical solutions for developers and IT leadership. Today he heads Agile SEO, the leading marketing agency in the technology industry.

LinkedIn: https://www.linkedin.com/in/giladdavidmaayan/

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