Creating cloud-native applications requires not only new ways of thinking, but a cultural shift to take full advantage of modern design and delivery models. Building resilient software architectures on top of proven cloud services is not just a technological challenge, it also becomes more about decentralized decision making, building strong internal platforms and automating innovation with continuous delivery to iterate faster.
As your company enters a transitional phase with cloud-native development, you have to implement key strategies that lead the way in how swiftly people are able to move while keeping the risks at bay. In this post we will go through one of the most important techniques for cloud-native deployment: Canary releases. We will detail what makes them so, how to deploy them and a few of the drawbacks you might encounter. We will give concrete examples using the most popular cloud-native tools and when they should be used in your existing software development lifecycle (SDLC).
What is a Canary Release?
Canary – Bird which coal miner to take inside coal mines so that it senses the toxic gasses. In this way, the miners have a system of early warning; when canary birds stop singing or die, they know that gasses are present and evacuate immediately. Canary Release or Canary Deployment is basically a release strategy that is used to test new software in the deployment process just before taking that new software to all users live. So that it acts as a safeguard before deploying as a whole.
It helps development teams go progressively, and reduces the risk of failure. In a deployment, if any error occurs then only a small number of users will fall into trouble so we can roll-back our deployment even before it drastically hits others.
Sometimes, Canary release strategy may conflict with feature flags, blue-green deployments or dark launches but these three are other practices.
The Blue-Green deployment pattern consists in having two separate production environments (blue and green) for example, all the traffic is sent to only one of them at a time. Canary deployment refers to a gradual release of the changes in production, which automatically supports rigorously acquired testing sequentially.
Feature flags affect what specific subset of users will have access to a particular feature, canary release tests entire version.
A dark launch releases a new feature to Production without affecting users. Dark launch involves the same set of users calling into the new modified code without the user being aware of it. In reality, it silently performs a new work of collecting performance information without user approval.
Using EnRoute Ingress Controller for canary releases
Why Canary Releases Matter
With modern software development moving faster than it ever has, there is a demand to increase release velocity. But the quicker you ship, there is more risk involved in that. Canary deployments offer a balance between speed and safety by allowing teams to test new code in a realworld environment without impacting the entire user base.
Canary Deployment Strategy: Things to keep in mind
1. Risk Reduction
You only put a fraction of your users at risk with the new version which minimizes blast radius. Rather than every user being impacted by a bug or performance issue, only some of the users see that problem. That makes it easier to troubleshoot a new software deployment and fix it before a wider rollout. Canary releasing software reduces risk.
2. Real-World Feedback
Pre-production environments are great, but the complexity of production cannot be perfectly replicated in pre-production environments. Canary releasing features allows us to get feedback form real users under the most realistic conditions possible, and those are useful insights compared to all things that can happen in staging environments.
3. Cycle Faster
Canary releases help teams move faster and deliver more updates over time. An incremental rollout allows a more iterative development, with continuous delivery and less downtime or disruption compared to bigger monolithic releases.
When To Use Canary Releases
Canary release is not the only solution but it can be one of the best in some situations like if you have a very complex architecture, moving from monolithic to micro-service etc. Some such scenarios include:
Microservice Architecture: A microservice is dependent upon various other microservices to interact where every service has their own developments and changes; Teams can do rolling updates of a single service in the system (canary release).
High-Risk Deployments: If a deployment of any feature, or update involves high risk/performance issues, canary release gives a safer play-ground for experiment in releasing an update. You can direct small group of users to the new canary version of the software and monitor its impacts.
Third Party Dependencies: If your application has third party dependencies or legacy systems where you are not able to test in a pre-production environment, canary release helps us test them without complete failure in production.
On the other hand, there are some situations where canary release may not be appropriate:
Mission Critical Systems: Canary release is not suitable for mission critical applications where even small errors could have serious consequences or may cost a lot.
High Sensitivity Users: Sometimes users are working on sensitive data such as financial applications where a minor error can lead to a significant monetary loss, canary release is not recommended in such systems.
Incompatible Backend Changes: If your release involves significant changes to the backend, such as a database schema update that is not backward-compatible, canary releases can be challenging to manage. You’ll need to carefully plan how the new and old versions will coexist during the transition period.
How to implement Canary Release
Implementing a canary release is a combination of technical infrastructure and operational practices.
Set up monitoring and observability: Before rolling out the canary release, you must have a good monitoring system. It is paramount that you can observe the changes over in your application system. This involves tracking technical metrics and tracking business metrics as well. Without observability, it is difficult to know whether the canary is successful or not, without proper monitoring.
Use Programmable Load Banlancers: When it comes to traffic routing in portion in some cases you need a load balancer, proxy or API Gateway. In canary releases it is called programmable traffic routing. Popular tools like Envoy Proxy, HAProxy, or the EnRoute API Gateway (powered by CNCF Envoy-proxy project) can help manage traffic routing.
Automate Traffic Shaping: Traffic in canaries should be gradually increased. Starting small and gradually increasing as confidence in the new version grows. This process can be automated with popular tools like Jenkins, Spinnaker or LaunchDarkly.
Ensure Declarative Configuration: It’s a good practice to store the configuration of your canary release process in a declarative format (such as YAML), which fits into a GitOps workflow. This allows you to easily version-control your release strategy, enabling auditability and disaster recovery.
Plan for schema changes: If your update is related to a change in the database schema, you should be extra careful to manage the transition. Techniques like the expand and contract pattern (where the old schema is expanded to support the new version, and only contracted after the migration is complete) can help prevent service disruptions.
Automate rollback Mechanisms: Canary releases are most effective in rolling deployments when they include an automated rollback strategy. If your monitoring detects an issue, you should be able to quickly route traffic back to the old stable version or revert the deployment altogether. This ensures that any problems are resolved quickly, minimizing user impact.
Stages of canary release
Benefits and Challenges of Canary Releases
Benefits:
Reduce Risk: The biggest advantage of canary releases is that you mitigate several risks from deployment failures. Because the users initially affected are only a tiny fraction of all your users, dealing with issues before they expand to general availability is doable.
Continuous Delivery: Continued delivery helps team to release small update frequently and fast. Canary releases practices enable teams to release updates in an automated way without interruption. This aligns with modern continuous delivery practices and reduces the pressure of deploying large, monolithic updates.
Real-Time Feedback: Canary releases provide valuable insights by exposing new software to real users in real environments. This real-time feedback helps teams identify issues that might not appear in pre-production testing.
Challenges
Complexity: Canary release pipelines are a complex methodology to implement. It needs strong monitoring, traffic management tools and automation. Developing this infrastructure needs time and resources which may challenge for a smaller team.
Limited value without observability: Canary releases effect mostly depends on quality observability of deployment and system. Without strong monitoring system you might miss critical error.
Data management: Handling changes to data stores and managing schema updates can be tricky, especially if the new version and old stable version need to coexist during the transition. This requires careful planning and testing to avoid service disruptions.
Conclusion
Canary release is a powerful strategy for deploying software safely and effectively. As it gradually rolls out the changes over the small subset of users and sequentially covers more users, teams can easily detect any issue early and mitigate the risk of application release failures. Though canary releases have some challenges, it has benefits in terms of reduced risk, faster iteration, and real world feedback. Canaray releases are an essential tool for modern cloud native development.
To succeed with canary releases, focus on building a strong foundation of observability, automation, and traffic management. With the right tools and practices in place, your team can confidently deliver new features faster while maintaining the stability and reliability your users expect.
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