What Are Serverless Applications?
Serverless applications are a type of cloud-native application that are designed to run in a serverless computing environment. Serverless computing is a cloud computing model in which a cloud provider dynamically allocates resources to run an application or service, based on the actual needs of the application at any given time. In this model, the cloud provider is responsible for managing the underlying infrastructure and scaling resources up or down as needed, and the developer is only responsible for writing the code that runs on the platform.
Serverless applications are typically built using a combination of functions-as-a-service (FaaS) and managed services. FaaS is a type of cloud service that allows developers to write and deploy code in the form of individual functions, which are then triggered by certain events or requests. Managed services are cloud-based services that provide various types of functionality, such as cloud database services, messaging services, and more, without the need for the developer to manage the underlying infrastructure.
What Is Canary Deployment?
Canary deployment is a software deployment strategy that involves releasing a new version of an application or service to a small subset of users, before rolling it out to the entire user base. The goal of canary deployment is to test the new version of the application in a real-world environment, in order to identify any issues or problems before they affect the entire user base.
In a canary deployment, the new version of the application is usually deployed to a small group of users, often referred to as a “canary group.” This group is typically representative of the overall user base, and is chosen to ensure that any issues that are discovered during the canary deployment will be representative of the types of issues that might be encountered when the new version is rolled out to the entire user base.
How Canary Deployments Work
During the canary deployment, the new version of the application is monitored closely to ensure that it is functioning as expected. This may involve monitoring various performance metrics, such as response time, error rates, and resource utilization, as well as collecting feedback from users in the canary group.
If the new version of the application performs well and does not encounter any issues during the canary deployment, it can be rolled out to the entire user base with confidence. On the other hand, if issues are discovered during the canary deployment, they can be addressed before the new version is rolled out to the entire user base, reducing the risk of disruptions or other problems.
There are two main types of canary deployment: rolling and side-by-side deployments.
Rolling Deployment
In a rolling deployment, the new version of the application is gradually rolled out to the entire user base, starting with a small group of users and then gradually increasing the number of users over time. This allows the new version of the application to be tested in a real-world environment, while minimizing the risk of disruptions or other issues.
For example, let’s say that you have an application with 100 users. In a rolling deployment, you might start by deploying the new version of the application to a canary group of 10 users. If the new version performs well and does not encounter any issues during the canary deployment, you might then roll it out to an additional 20 users, and so on, until the new version is deployed to the entire user base.
Side-by-Side Deployment
In a side-by-side deployment, the new version of the application is deployed alongside the existing version, and a small subset of users is routed to the new version. This allows the new version to be tested in parallel with the existing version, allowing you to compare the performance of the two versions side by side.
For example, let’s say that you have an application with 100 users. In a side-by-side deployment, you might deploy the new version of the application alongside the existing version, and route a canary group of 10 users to the new version. If the new version performs well and does not encounter any issues during the canary deployment, you might then increase the number of users routed to the new version, until it is deployed to the entire user base.
Suggested Read: Integration of Cloud Computing with Web Applications
Why Are Canary Deployment Important to Serverless Applications?
Canary deployment is especially important for serverless applications because it allows you to test the performance of the new version of the function in a production environment before rolling it out to all users. This can help identify any issues with the new version of the function and minimize the risk of disrupting the application.
In addition to reducing the risk of downtime, canary 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.
To perform a canary deployment for a serverless application, you can use a load balancer or a reverse proxy to route a small percentage of traffic to the new version of the function and monitor the performance of the function using tools such as monitoring and logging. If the performance of the new version is satisfactory, you can gradually increase the percentage of traffic being routed to the new version until it is serving all users. If there are any issues with the new version, you can roll back to the previous version by routing all traffic back to the old function.
Best Practices for Using Canary Deployment in Serverless Applications
Here are some best practices for using canary 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 a small percentage of traffic to the new version of the function. This allows you to test the performance of the new version in a production environment with a limited number of users.
- Monitor the performance of the new version of the function closely after it is deployed. This can involve using monitoring and logging tools to track the performance of the function and identify any issues.
- 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 old and new versions of the function, or using a tool like AWS CodeDeploy to automate the rollback process.
- Gradually increase the percentage of traffic being routed to the new version of the function as you gain confidence in its performance. This can help ensure a smooth rollout of the new version.
Conclusion
Canary deployment is particularly important for serverless applications, which are built using a combination of functions-as-a-service (FaaS) and managed services. Serverless applications allow developers to focus on writing code, rather than worrying about managing and scaling the underlying infrastructure, but this also means that it can be more difficult to test and debug serverless applications.
By following best practices, such as starting with a small canary group, monitoring performance metrics and user feedback, using feature flags to control the rollout, using automated testing to validate the new version, and having a rollback plan in place, you can effectively use canary deployment to minimize the risk associated with deploying new versions of serverless applications, and to ensure that new releases are stable and reliable.
Also Read: Advantages of API-centric web application Development
