Practice : Canary Releases
Purpose and Strategic Importance
Canary releases allow teams to deploy changes to a small subset of users before rolling out more broadly. This progressive delivery technique helps reduce risk, improve resilience, and validate assumptions in production with real users.
Instead of deploying to all users at once, canary releases provide an early warning system - allowing engineers to monitor key metrics, detect anomalies, and halt or roll back changes before widespread impact occurs. They enable faster, safer releases and reinforce a culture of learning and control.
Description of the Practice
- New features or changes are first deployed to a limited segment of users (e.g. internal, by region, or % of traffic).
- Automated monitoring is used to track errors, performance, and user behaviour during the canary phase.
- If no issues are detected, the release is gradually expanded to a wider audience.
- Rollback mechanisms are in place to quickly revert if problems are found.
- Canary strategies are embedded in deployment pipelines or release orchestration tools.
How to Practise It (Playbook)
1. Getting Started
- Identify a release candidate that carries risk or would benefit from real-world validation.
- Configure your delivery platform (e.g. Kubernetes, LaunchDarkly, Azure DevOps) to support segmented traffic.
- Start with internal users or 1–5% of live traffic as your canary group.
- Define clear success and failure criteria before starting the canary.
2. Scaling and Maturing
- Automate rollout logic - use pipelines that promote based on success signals or manual triggers.
- Integrate real-time telemetry dashboards to monitor service health, latency, and error rates during canaries.
- Add safeguards like automated halts, threshold alerts, and traffic shaping.
- A/B test different versions alongside canary releases for deeper insights.
- Establish policies for when to expand, pause, or roll back based on observed impact.
3. Team Behaviours to Encourage
- Plan for rollback - don’t treat failure as a surprise.
- Pair engineers with product or operations during high-risk releases.
- Treat incidents during canaries as learning opportunities, not just technical failures.
- Share learnings from canary results across teams to spread insight.
4. Watch Out For…
- Releasing without observability - a canary without visibility is blind risk.
- Skipping canary in favour of full deploys "because it's faster."
- Inconsistent traffic allocation that skews results.
- Over-relying on manual checks without automated metrics to drive rollout.
5. Signals of Success
- Canary results influence rollout decisions with data, not intuition.
- Teams have confidence in their ability to release quickly and safely.
- Rollbacks are fast, tested, and happen without incident.
- Operational risk is significantly reduced for complex or critical changes.
- Canary releases are part of routine delivery, not reserved for emergencies.