Blue Green deployment and canary testing are two popular strategies used in software development to minimize risks and disruptions when deploying new versions of an application.
In a traditional blue-green deployment, there are two identical production environments, referred to as blue and green. The blue environment represents the current live version of the application, while the green environment is a replica of the blue environment that is used for testing and deploying new versions of the application.
With a blue-green deployment, the new version of the application is deployed to the green environment and tested extensively before it is switched over to the blue environment. This approach ensures that any issues or bugs in the new version are caught early and does not affect the live application.
Canary testing, on the other hand, is a strategy that involves deploying a new version of the application to a small subset of users or servers, often referred to as the “canary group”. This group receives the new version of the application while the rest of the users continue to use the stable version.
The purpose of canary testing is to gradually expose the new version of the application to a larger audience, monitoring its performance and gathering feedback before rolling it out to all users. This allows for early detection of any issues or bugs that may arise in the new version without impacting the entire user base.
Benefits of Canary Testing
Canary testing is a deployment strategy that allows for the gradual rollout of new features or updates in a controlled manner. It involves exposing a small percentage of users or a specific subset of the infrastructure to the changes while the rest remain on the stable version, also known as the blue environment.
There are several advantages of canary testing compared to traditional blue-green deployments:
1. Reduced Risk
By gradually rolling out changes to a small subset of users, any potential issues or bugs can be identified and mitigated before affecting a larger audience. This approach minimizes the risk of widespread issues and allows for quick fixes.
2. Early Feedback
Canary testing enables teams to gather early feedback from users who are exposed to the new features. This feedback can be valuable for fine-tuning and making necessary improvements before rolling out the changes to all users.
3. Performance Monitoring
During canary testing, performance metrics and monitoring tools can be used to analyze the impact of the changes. This allows teams to identify any performance issues, compare them to the stable environment, and make data-driven decisions.
4. Seamless Rollback
If any issues are detected during canary testing, it is much easier to roll back the changes as only a small percentage of users or infrastructure is affected. This allows for quick and seamless rollback without impacting the majority of users.
5. Gradual Adoption
Canary testing allows for a gradual adoption of new features or updates. This approach is particularly useful for large-scale deployments where sudden changes can overwhelm the system. By gradually increasing the percentage of users exposed to the changes, teams can ensure a smoother transition.
Overall, canary testing offers a more controlled, less risky, and user-centric approach to testing and deploying changes compared to the traditional blue-green strategy. It allows teams to make data-driven decisions, minimize the impact of potential issues, and ensure a seamless user experience.
Advantages of Blue Green Deployment
When it comes to deploying software updates or new features, there are several advantages to using the blue-green deployment strategy.
First and foremost, blue-green deployment allows for a safe and risk-free testing of new changes. By having both a green and blue environment, developers can test their updates in isolation without affecting the live production environment. This ensures that any issues or bugs can be caught and resolved before they impact users.
Another advantage of blue-green deployment is the ability to easily rollback changes if necessary. In the event that a new update causes unexpected issues or performance problems, the deployment can be quickly reversed by redirecting the traffic back to the green environment. This minimizes downtime and allows for a seamless transition back to a stable version of the software.
Additionally, blue-green deployment offers a higher level of availability and reliability. With two identical environments running in parallel, the green environment serves as a backup that can take over instantly in case of a failure or outage in the blue environment. This ensures that users experience minimal disruption and can continue using the application without interruptions.
Furthermore, blue-green deployment enables efficient testing of scalability and performance. By gradually routing traffic from the green to the blue environment, developers can assess how the new changes behave under different loads and identify any potential bottlenecks or performance issues. This allows for effective optimization and tuning of the software to handle increased user demand.
Overall, the blue-green deployment strategy provides numerous advantages when compared to traditional testing methods. It offers a safe testing environment, easy rollback capabilities, increased availability, and efficient scalability testing. These benefits make it a preferred choice for organizations looking to continuously deliver high-quality software updates to their users.
Key Differences between Canary Testing and Blue Green:
Both Canary Testing and Blue Green are popular deployment strategies, used to mitigate risks and ensure the stability of software releases. However, there are significant differences between the two approaches.
Canary Testing:
Canary Testing involves rolling out new features or updates to a limited subset of users or systems before deploying them to the entire user base. This subset is referred to as the “canary group.” The purpose of Canary Testing is to catch any issues or bugs early on, while minimizing the potential impact on the wider user base.
Key characteristics of Canary Testing include:
- Progressive rollout: New features are released gradually to the canary group, allowing for both monitoring and comparison with the existing stable version.
- Real-time monitoring: Canary users are closely monitored for any anomalies or issues that may arise.
- Rollback capabilities: If any critical issues are detected, the deployment can be immediately rolled back in order to minimize the impact on users.
Blue Green:
Blue Green deployment involves having two identical environments, referred to as “blue” and “green.” One environment (blue) is active and serves live traffic, while the other (green) is idle. When a new release is ready, it is deployed to the idle environment (green) and tested extensively. Once the new release is verified, traffic is switched from the active environment (blue) to the new release (green).
Key characteristics of Blue Green deployment include:
- Zero downtime: The switch from the old release to the new release is seamless, ensuring there is no interruption in service.
- Quick rollback: If any issues are detected in the new release, the switch can be easily reversed, instantly reverting back to the previous release.
- Costly resource duplication: Blue Green deployment requires maintaining two identical environments, which can be resource-intensive and costly.
| Canary Testing | Blue Green |
|---|---|
| Progressive rollout to a limited user group | Switch from one environment to another |
| Real-time monitoring of canary users | Zero downtime during the switch |
| Potential impact limited to canary users only | Resource duplication to maintain two environments |
In conclusion, while both Canary Testing and Blue Green provide methods for deploying software releases with reduced risk, they differ in their approach. Canary Testing focuses on gradually rolling out new features to a limited group of users for monitoring and comparison, while Blue Green deployment involves seamlessly switching live traffic from one environment to another. The choice between the two strategies depends on the specific needs and resources of the organization.
How Canary Testing Works
Canary testing, also known as canary releases, is a testing technique that involves rolling out a new software version or feature to a subset of users, usually referred to as the “canary group” or “canary users”, while the majority of users remain on the stable version, known as the “green group”. This subset of users acts as the early adopters who help identify any potential issues or bugs before the software is fully released to all users.
Unlike blue-green testing, where two complete environments, the green and blue, are set up and switched between, canary testing involves deploying the new version alongside the existing stable version in the same environment. This allows for a phased or gradual rollout, where a small percentage of users are exposed to the changes while the impact is monitored closely.
Deployment Process:
The canary deployment process typically involves the following steps:
- Selecting a small percentage of users or specific criteria for the canary group.
- Deploying the new version to the canary group alongside the existing stable version.
- Monitoring the canary group for any issues, such as increased error rates or decreased performance.
- If no major issues are detected, gradually increase the exposure by rolling out to a larger percentage of users.
- Continuously monitor the system during the rollout and be prepared to roll back if necessary.
- Once the new version has been successfully rolled out to the entire user base, the canary testing phase is complete.
Benefits of Canary Testing:
Canary testing offers several benefits:
- Early detection of potential issues or bugs before impacting a large user base.
- Ability to gather feedback from the canary group and make improvements before releasing to all users.
- Reduced risk of downtime or disruption by gradually rolling out the new version.
- Opportunity to assess the performance and impact of the new version in a controlled manner.
Overall, canary testing provides a controlled and gradual approach to software releases, allowing for early detection of issues and minimizing the impact on users.
How Blue Green Deployment Works
Blue Green deployment is a release management strategy that allows organizations to minimize downtime and reduce the risk of deploying software updates. The approach involves maintaining two production environments, the blue environment and the green environment. At any given time, only one of these environments is live and serving traffic, while the other remains idle.
The blue and green environments are identical, and they are set up in such a way that switching between them is seamless. This makes it easier to test new releases and roll them back if any issues are detected. When a new version of the software is ready to be released, it is first deployed to the idle environment (green). This allows for thorough testing and verification without affecting the live production environment.
Once the new version has been tested and deemed ready for production, the switch from blue to green is performed. Traffic is redirected to the green environment, and the blue environment becomes idle. This transition can be done gradually or all at once, depending on the organization’s deployment strategy and risk tolerance.
The blue environment, which was previously live, now becomes the idle environment. This provides a fallback option in case any issues are encountered in the green environment. If any problems are detected after the switch, the deployment can be easily rolled back by redirecting traffic back to the blue environment. This ensures minimal disruption to the end users.
In summary, blue green deployment allows organizations to release new software versions with confidence. By keeping two identical environments and carefully managing the switching process, organizations can minimize downtime, eliminate risks associated with deploying untested code, and provide a seamless experience for their users.
When to Use Canary Testing
Canary testing is a valuable technique to use when you want to test new features or changes in a controlled environment before deploying them to your entire user base. By gradually rolling out the changes to a small subset of users, you can monitor how the new version performs and catch any potential issues early on.
This approach is particularly useful when you are making significant updates to your application or infrastructure, or when you are introducing a new feature that could potentially have a large impact on your users. By using canary testing, you can minimize the risk of deploying a faulty or problematic change to all your users at once.
In contrast to blue-green testing, which involves switching between two identical environments, canary testing allows you to test changes in a live production environment. This provides you with more accurate and realistic data about how the new version will perform in real-world conditions.
Overall, canary testing is a powerful tool for ensuring the stability and reliability of your application. By gradually releasing new changes and closely monitoring their impact, you can make informed decisions and confidently roll out the updates to your entire user base.
When to Use Blue Green Deployment
Blue Green Deployment is a deployment strategy that involves having two separate environments, known as “blue” and “green”, for running your application. Each environment is identical and has its own set of resources, such as servers and databases.
The main purpose of Blue Green Deployment is to ensure zero-downtime deployment, as it allows you to seamlessly switch between the two environments without affecting the availability of your application to users. This makes it an ideal choice for critical production environments where downtime is not an option.
Advantages of Blue Green Deployment
Blue Green Deployment offers several advantages over traditional deployment methods:
- Reduced risk: With Blue Green Deployment, you can easily roll back to the previous environment (blue) if any issues or failures occur in the new environment (green), minimizing the impact on users.
- Quick rollback: Switching back to the previous environment is a matter of routing the traffic to the blue environment, allowing for fast and efficient rollback in case of failure.
- Easier testing: Blue Green Deployment provides a separate environment (green) where you can safely test your changes before routing the traffic to it. This ensures that the new version of your application is thoroughly tested and stable before being exposed to users.
- Efficient resource utilization: Blue Green Deployment allows you to keep both environments up and running at all times, enabling efficient resource utilization and effectively utilizing your infrastructure.
When to Choose Blue Green Deployment
Blue Green Deployment is particularly beneficial in the following scenarios:
- High availability requirements: If your application needs to be available 24/7 with minimal downtime, Blue Green Deployment is an excellent choice.
- Large-scale deployments: Blue Green Deployment is well-suited for large-scale deployments that involve multiple servers and complex infrastructure setups.
- Avoiding user disruption: If you want to avoid disrupting the user experience during deployment, Blue Green Deployment ensures smooth transitions and uninterrupted availability.
- Ensuring reliable testing: With Blue Green Deployment, you can perform thorough testing in a separate environment, ensuring that your changes are stable and reliable before exposing them to users.
In summary, Blue Green Deployment is an excellent choice for critical production environments that require zero-downtime deployments, efficient testing, and maximum availability. It offers reduced risk, easy rollbacks, and efficient resource utilization, making it a reliable and flexible deployment strategy.
Challenges of Canary Testing
Canary testing, also known as canary releasing or canary deployment, is a technique used in software development and deployment to mitigate risks associated with new releases. It involves gradually rolling out changes or new features to a subset of users or infrastructure, while monitoring the performance and stability of the system. However, like any testing method, canary testing also comes with its own set of challenges.
1. Gradual Rollout
In canary testing, the changes are released incrementally to a small subset of users or infrastructure. This gradual rollout process can be challenging to manage, especially in large-scale deployments. Coordination and monitoring become crucial to ensure that the changes are progressing smoothly and no major issues are encountered during the rollout.
2. Identifying Canary Users
Selecting the subset of users or infrastructure to release the changes to is another challenge in canary testing. The canary users need to be representative of the overall user base and infrastructure, but also willing to participate in the testing process. Identifying these users can be time-consuming and requires careful consideration to ensure accurate results.
| Testing | Blue | Green | Canary |
|---|
Overall, while canary testing offers many benefits, such as reducing the impact of potential issues and validating the success of changes before a full release, it also presents challenges that need to be addressed for effective implementation.
Challenges of Blue Green Deployment
Blue Green deployment is a popular strategy for managing updates and minimizing downtime in software development. Compared to Canary testing, Blue Green deployment presents its own set of challenges.
1. Infrastructure Complexity
One of the main challenges of Blue Green deployment is managing the complexity of the infrastructure. In this approach, two identical environments, known as Blue and Green, are required to run simultaneously. This means that both environments must be set up and maintained, which can be time-consuming and resource-intensive.
Additionally, the complexity of managing the routing between the two environments can also be a challenge. Load balancers or reverse proxies are often needed to direct traffic to the correct environment, and the configuration of these routing mechanisms can be error-prone.
2. Resource Utilization
Another challenge of Blue Green deployment is efficiently utilizing resources. Since both the Blue and Green environments need to be running simultaneously, it can lead to excess resource allocation. This is especially true if there are periods of low traffic or if the deployment process takes a long time.
Companies need to carefully plan and monitor resource allocation to ensure efficient usage and avoid unnecessary costs. Scaling the environments dynamically based on actual traffic patterns can help mitigate this challenge.
Overall, while Blue Green deployment offers benefits such as zero-downtime updates and easy rollback, it also presents challenges in terms of infrastructure complexity and resource utilization.
Best Practices for Canary Testing
When it comes to implementing canary testing, there are several best practices that can help ensure its success. Comparing canary testing vs blue-green testing, canary testing allows for a more gradual and controlled release of new features or changes. Here are some key considerations:
1. Start with a small percentage:
Begin by releasing your canary version to a small percentage of your user base. This allows you to monitor the impact of the changes more closely and identify any issues that may arise without affecting all users simultaneously.
2. Monitor your metrics:
Set up comprehensive monitoring and metrics to track the performance and behavior of your canary version. This includes monitoring system health, response times, error rates, and user interactions. By closely monitoring these metrics, you can quickly detect and address any abnormalities or regressions.
3. Gradually increase the rollout:
If the canary version is performing well and meeting your success criteria, gradually increase the percentage of users who receive the update. This allows for a controlled and incremental release, giving you more opportunities to identify and fix any issues that may arise.
4. Define clear success criteria:
Prior to implementing canary testing, clearly define the key metrics and thresholds that will determine the success or failure of the canary version. This will help you objectively evaluate the impact of the changes and make informed decisions about the rollout.
5. Have a rollback plan:
Despite careful testing and monitoring, issues may still arise once the canary version is rolled out to a larger audience. It is important to have a well-defined rollback plan in place to quickly revert to the previous version if necessary. This can help minimize any negative impact on user experience and business operations.
6. Communicate with stakeholders:
Keep stakeholders informed about the canary testing process, including the goals, progress, and results. This helps manage expectations and ensures that everyone is aligned on the objectives and potential risks associated with the canary rollout.
By following these best practices, canary testing can be an effective and controlled approach to deploying new features or changes, ensuring a smooth transition for both users and development teams.
Best Practices for Blue Green Deployment
Blue Green deployment is a software release management strategy that allows for seamless updates without any downtime. In this context, the terms “blue” and “green” refer to two distinct environments, where one environment is live (blue) and the other is idle (green).
When implementing a Blue Green deployment, it is important to follow some best practices to ensure a smooth and successful release:
-
Automate the deployment process:
Automating the deployment process reduces the chances of human error and makes it easier to roll back in case of any issues. Continuous integration and deployment tools can help automate the process and ensure consistent deployments.
-
Have a comprehensive rollback plan:
Even with careful planning, issues can still occur during deployment. It is crucial to have a well-defined rollback plan in place to quickly revert back to the previous version if needed. This plan should include steps to switch the traffic back to the previous environment.
-
Monitor and test the green environment:
The idle environment (green) should be continuously monitored and tested to ensure it is ready to handle traffic. This includes verifying dependencies, database connections, and performance metrics. Regular testing and monitoring help uncover any issues before switching the traffic.
-
Gradually redirect traffic:
Instead of instantly redirecting all traffic to the green environment, it is recommended to gradually route a small amount of traffic to the new environment (canary testing). This allows for monitoring the performance and stability of the new release. If everything is successful, the traffic can be gradually shifted towards the green environment.
-
Keep the idle environment up-to-date:
It is important to keep the idle environment (green) up-to-date with the latest changes from the active environment (blue). This ensures that when it’s time to switch the traffic, there won’t be any compatibility or configuration issues.
By following these best practices, organizations can successfully implement Blue Green deployments, minimize downtime, and ensure a smooth release process.
Case Studies: Canary Testing
In the world of software development and deployment, two popular methodologies for ensuring the quality of new releases are Canary Testing and Blue Green Deployment. In this article, we will focus on the specific use case of Canary Testing.
Canary Testing is a technique used to gradually introduce new features or changes to a subset of users or systems, while keeping the majority of users unaffected. This allows for real-time monitoring and evaluation of the changes before a full rollout. It is often used in scenarios where there is a need for continuous delivery and frequent updates.
One noteworthy case study involving Canary Testing is the release of a major banking application. The development team implemented a new feature that aimed to enhance the user experience in conducting online transactions. However, due to the sensitive nature of financial transactions and potential risks associated with introducing untested changes, the team decided to deploy the feature using Canary Testing.
The Canary Testing process involved selecting a small group of users who were willing to participate in the test. The new feature was enabled for this group, while the rest of the users continued to use the existing version of the application. The team closely monitored the performance of the new feature, including transaction success rates, response times, and user feedback.
During the Canary Testing period, the team identified and resolved several minor issues related to transaction processing and user interface. These issues would have caused significant disruptions if they had been rolled out to the entire user base at once. By using Canary Testing, the team was able to catch and fix these problems before they impacted a larger number of users.
The Canary Testing period lasted for two weeks, during which the team made constant improvements and refinements based on the feedback received from the participating users. After the successful completion of the test phase, the new feature was gradually rolled out to the entire user base, ensuring a smooth and error-free deployment.
| Advantages of Canary Testing | Disadvantages of Canary Testing |
|---|---|
|
|
Case Studies: Blue Green Deployment
When it comes to implementing a new software release without interruption to the production environment, the Blue Green deployment strategy has proven to be very effective. This approach allows for a seamless transition from the current stable version (blue) to the new version (green) by running both versions simultaneously. Here are two case studies that highlight the success of the Blue Green deployment strategy versus traditional canary testing:
Case Study 1: E-commerce Platform
An e-commerce platform decided to adopt the Blue Green deployment strategy to ensure a smooth release of their latest update. By using this strategy, they were able to mitigate the risks associated with deploying a new version by running it alongside the stable version. This allowed them to ensure that the new version was functioning correctly and compatible with their existing systems before fully transitioning to it. As a result, they experienced minimal downtime and were able to quickly address any issues that arose during the deployment process.
Case Study 2: Financial Services Provider
A financial services provider wanted to streamline their software release process and reduce the impact of potential bugs or issues on their customers. They implemented the Blue Green deployment strategy, which allowed them to deploy updates with confidence. By running both versions simultaneously, they were able to perform extensive testing and ensure a smooth transition to the new version. This approach significantly reduced the risk of disruptions for their customers and enhanced their overall experience with the platform.
Overall, these case studies demonstrate the benefits of using the Blue Green deployment strategy compared to canary testing. By running both the stable version (blue) and the new version (green) concurrently, organizations can minimize downtime, mitigate risks, and ensure a seamless transition to the latest release.
| Blue Green Deployment | Canary Testing |
|---|---|
| Simultaneous running of both versions | Gradual rollout of the new version |
| Reduced downtime | Potential downtime during canary phase |
| Enhanced ability to test and address issues | Less extensive testing during canary phase |
Real-world Examples of Canary Testing
Canary testing is a popular approach to testing and deploying software updates in real-world scenarios. It involves rolling out the updates to a small subset of users or a specific group of servers, often referred to as the “canaries.” This allows for a controlled and measured testing environment where any potential issues or bugs can be identified and addressed before a wider release.
One example of canary testing in action is the deployment of new features or changes to a web application. Instead of releasing these updates to all users at once, developers can first test them with a small group of users as canaries. This enables them to gather valuable feedback and identify any issues or performance problems that may arise.
Another real-world example of canary testing is in the context of mobile app development. Before rolling out a new version of an app to all users, developers can release it to a select group of beta testers. These testers act as canaries, providing feedback and reporting any bugs or usability issues they encounter. This helps ensure that the app is stable and user-friendly before a wide release.
Canary testing can also be useful in scenarios where infrastructure changes are being made. For example, when migrating databases or changing server configurations, canary testing allows for a gradual rollout to a subset of servers to ensure that everything is functioning as expected before scaling up.
In comparison, blue-green deployments involve having two separate environments, one active (“blue”) and one idle (“green”). The new version is deployed to the idle environment and then traffic is switched to it once it has been tested and verified. Canary testing, on the other hand, focuses on gradually rolling out updates to a small subset of users or servers, allowing for gradual testing and identification of any issues.
Overall, canary testing offers a controlled and measured approach to deploying software updates, ensuring that any potential issues are identified and addressed before they impact a wider user base or server infrastructure.
Real-world Examples of Blue Green Deployment
In the real world, many companies have successfully implemented the blue green deployment strategy to ensure smooth and seamless deployments. Here are some examples:
| Company | Description |
|---|---|
| Amazon | Amazon uses the blue green deployment approach to roll out updates to their online services, such as Amazon Web Services. By deploying the new version to a separate environment (the green environment), they can test it thoroughly before switching the traffic from the old version (the blue environment) to the new one. |
| Netflix | Netflix employs blue green deployments to ensure high availability and minimize downtime for their streaming platform. They switch the traffic gradually from the blue environment to the green environment, allowing them to spot any issues and roll back easily if needed. |
| Etsy | Etsy, the popular e-commerce website, also uses blue green deployments to reduce the impact of updates on their users. By deploying to a separate environment, they can verify the new version’s stability and performance without affecting the live website. |
These examples demonstrate how blue green deployments can be an effective strategy for minimizing downtime, reducing the risk of failures, and ensuring a smooth transition to new versions of software or services.
Final Thoughts on Canary Testing
In conclusion, canary testing is a crucial component of modern software development. By gradually rolling out changes to a small subset of users, known as the “canary”, developers can effectively monitor and assess the impact of their updates before deploying them to the wider user base.
Compared to blue-green testing, canary testing offers several advantages. The ability to carefully control and monitor the canary users provides a level of granularity that is not possible with blue-green testing. Additionally, canary testing allows for more targeted and efficient bug detection and remediation, as issues are identified and resolved before they affect the larger user base.
However, it is important to note that canary testing is not a one-size-fits-all solution. Depending on the specific needs and constraints of a project, blue-green testing may be a more suitable approach. It is crucial for development teams to carefully evaluate their requirements and select the testing strategy that best aligns with their goals.
In summary, while canary testing offers a powerful way to ensure smooth and reliable software updates, it should be seen as a complementary approach to blue-green testing rather than a replacement. Both strategies have their strengths and weaknesses, and a thoughtful evaluation is necessary to determine which approach will yield the best results for a given project.
Question-answer:
What is canary testing in software development?
Canary testing is a software testing technique in which a small number of users or a particular subset of users are exposed to a new version of the software while the majority of the users continue to use the stable version. By monitoring the behavior of the canary users, developers can quickly identify and mitigate any issues or bugs before rolling out the new version to all users.
What is blue-green deployment?
Blue-green deployment is a software release management strategy in which two separate environments, known as blue and green, are maintained. The blue environment represents the stable version of the software that is currently in use by the users, while the green environment contains the new version of the software that is being tested. By switching the user traffic from the blue environment to the green environment, developers can test the new version without affecting the users. If any issues are detected, the traffic can be switched back to the blue environment to ensure uninterrupted service.
What are the advantages of canary testing?
Canary testing allows developers to identify and fix issues with a new version of the software before it is rolled out to all users. This helps prevent widespread downtime or disruption in the event of bugs or performance issues. Canary testing also allows developers to collect real-time data and feedback from the canary users, which can be used to make informed decisions and improvements to the software.
What are the advantages of blue-green deployment?
Blue-green deployment minimizes the risk associated with releasing a new version of the software. By maintaining two separate environments, developers can easily switch the user traffic back to the stable version if any issues occur. This ensures that users experience minimal downtime or disruption. Blue-green deployment also allows for seamless rollback to the previous version in case any critical issues are detected during the testing phase.
Can canary testing and blue-green deployment be used together?
Yes, canary testing and blue-green deployment can be used together to further enhance the software release process. By combining the canary testing approach with the blue-green deployment strategy, developers can gradually expose a small number of canary users to the new version of the software in the green environment. This allows for a more controlled and incremental rollout, ensuring that any issues are identified and resolved before the new version is made available to all users in the blue environment.