Approaches to Achieving Zero-Downtime Deployments
As the name suggests, a zero-downtime deployment is one where there is no disruption to your application or service. This means that it can be deployed without causing any downtime for your service users. While this may sound like an impossible feat, there are some ways to achieve this goal. In this post, we’ll look at some approaches to help you achieve zero-downtime deployments for your applications, so you don’t have to worry about downtime when deploying updates!
Why does downtime happen?
Downtime can happen for a variety of reasons, but the most common are:
- Issues with the application – If you’re a developer, you’re probably familiar with this scenario: You’ve worked on a new feature for weeks and finally sent it through QA. It looks like everything is ready to go; however, once it’s deployed and users begin interacting with it, they report that some feature isn’t working as expected.
- Infrastructure issues – This can be anything from an issue in your load balancer configuration to a misconfigured DNS entry pointing to the wrong IP address (or even one pointing nowhere).
- Issues with the deployment process – This includes inadequate testing procedures or creating too many manual steps in your deployment process, which causes delays before code is applied into a production environment.
How to achieve zero-downtime deployments
In this article, we’ll examine the different approaches to achieving zero-downtime deployments and look at an approach that can help you get started. You’ll learn about blue-green deployments, rolling deployments, and canary deployments—all of which have pros and cons.
At the same time, dependency resolution is vital to achieving zero-downtime deployments. For example, when dealing with the dependency resolution of Rust crates, a Cargo registry can help you avoid downtime by providing a central location to store your dependencies.
What is blue-green deployment?
Blue-green deployment is a technique for deploying software to minimize disruption to users. A blue-green deployment is a type of continuous deployment, which means the new version of your software will be running in production within minutes of being built and tested.
Blue-green deployments are most effective when you have multiple web service endpoints or instances available for your application — or if you’re working with an external system that you need to vary across two different points in time (e.g., if one set of messages goes out through email, another through SMS).
The key idea behind this approach is that we maintain two identical environments: “blue” (production) and “green” (QA). We deploy our application into the green environment first, then switch traffic from one side to another, so it goes from blue->green->blue instead of just blue->green.
What is rolling deployment, and how do you use it?
Rolling deployment is a method that allows you to roll out new versions of an application to a subset of users. This can be useful for testing the new version before deploying it to all users. For example, if you are releasing a new feature or fixing a bug, rolling deployment makes it possible to test your changes in production. At the same time, they still have access only to specific users instead of all users at once.
Some companies choose not to use this approach because they want the change to reach everyone simultaneously. If you use rolling deployment, it’s crucial to have a clear plan for when you will release the new version. You can start with a small group of users and gradually expand the rollout as needed. For example, you might start with 10% of your users and then expand to 50% after an hour or two.
What is canary deployment, and how do you use it?
Canary deployment is a form of blue-green deployment, where you deploy a new version of software or configuration to a small subset of your users. Once you confirm that the changes work as expected, you can deploy them in stages until all users have access to the new version.
This approach can be used to test new features, but it’s more commonly used to test new software versions and configurations. For example, let’s say you have an application with two different configurations: one for production environments and another for development environments. You might want to run these tests on servers running in parallel so that if there are problems with either environment (or both), they don’t affect any production traffic—just test traffic from teams working on those environments.
With all these tools, you can potentially achieve a zero-downtime deployment process. In the long run, it will benefit your application and users by keeping them happy and engaged with your product or service.