Canary Deployments Explained
What Is a Canary Deployment?
Canary deployment is a technique used to reduce the risk of introducing a new software version in production by slowly rolling out the change to a small subset of users before rolling it out to the entire infrastructure. This can help to ensure that the new version does not have any unexpected problems or bugs that could impact the stability of the system.
In a canary deployment, the new version of the software is first deployed to a small group of users, often referred to as a “canary group.” The performance of the new version is then monitored closely to ensure that it is functioning as expected. If any issues are detected, the rollout can be stopped before it affects the entire user base. If the canary group does not experience any problems, the new version can be rolled out to the rest of the users.
Canary deployments can provide additional control and flexibility when rolling out new software versions, especially in conjunction with other techniques such as feature flags and blue-green deployments.
Canary Deployment Benefits
By rolling out the new version of the software to a small group of users, canary deployment allows you to test the capacity of the system and ensure that it can handle the load without any issues. This can help you to identify and fix any performance or scalability problems before they impact the entire user base.
Canary deployment is often used to test new versions of applications that have complex dependencies on other services or resources. By releasing the new version of the application to a small group of users or servers, the development team can ensure that the new version is able to successfully interact with its dependencies without impacting the entire user base.
This can be especially important when the new version includes changes to the application’s dependencies, as it allows the team to confirm that the changes have been implemented correctly and do not cause any issues with the application’s functionality.
By releasing the new version to a small group of users, you can gather early feedback on the changes and make any necessary adjustments before rolling it out to the rest of the users. This can help to improve the overall quality of the software and ensure that it meets the needs of your users.
If any issues are detected during the canary deployment, it is easy to roll back the change and return to the previous version of the software. This can help to minimize the impact of any problems and ensure that the system remains stable.
How Canary Deployments Work
Canary deployments are typically implemented as part of a continuous integration/continuous delivery (CI/CD) pipeline. In a CI/CD pipeline, changes to the software are automatically built, tested, and deployed to production.
There are several ways that canary deployments can be implemented within a CI/CD pipeline:
In a rolling deployment, the new version of the software is gradually rolled out to a small percentage of users at a time. This allows the system to be gradually tested and the performance of the new version to be monitored. If any issues are detected, the rollout can be stopped before it affects the entire user base.
In a side-by-side deployment, the new version of the software is deployed alongside the existing version. A small percentage of traffic is routed to the new version, while the rest is routed to the existing version. This allows the performance of the new version to be monitored and compared to the existing version. If any issues are detected, the rollout can be stopped before it affects the entire user base.
Planning a Canary Deployment
When planning a canary deployment, there are several factors to consider:
- Select a canary group: Determine the size of the canary group and select the users who will be included in the group. The canary group should be representative of the overall user base, but small enough to be manageable.
- Define the rollout plan: Determine how the new version will be rolled out to the canary group. Will it be a rolling deployment, where the new version is gradually rolled out to a small percentage of users at a time, or a side-by-side deployment, where the new version is deployed alongside the existing version and a small percentage of traffic is routed to it?
- Set up monitoring and alerting: Set up monitoring and alerting to detect any issues with the new version. This may include monitoring performance, error rates, and other metrics.
- Define the rollback plan: Determine how the rollback process will work if any issues are detected during the canary deployment. This may include defining the steps to be taken to roll back the change and return to the previous version of the software.
- Communicate the plan: Communicate the canary deployment plan to all relevant stakeholders, including the development team, the operations team, and any other relevant parties.
Overall, careful planning is key to a successful canary deployment. By considering these factors and establishing clear procedures, you can ensure that the rollout goes smoothly and that any issues are detected and addressed quickly.
To conclude, a canary deployment can help introduce a new software version in a way that allows gradually testing it on real users or beta users. It reduces the risks associated with releasing the version to all users and ensures you can roll back quickly if issues occur or the version proves unsuccessful. Be sure to plan your deployment in advance and select the most relevant canary group to ensure an effective deployment.