Blue-Green vs Canary Deployments: Which One Should You Use?
Blue-green vs canary deployments. Which one should you use? Both eliminate downtime. But they solve different problems.
Blue-Green Deployments
You maintain two identical environments. Blue is live. Green is your new version.
When you're ready:
- Route 100% of traffic to green
- Blue becomes your instant rollback
Best for:
- Major releases with significant changes
- Database schema migrations
- When you need clean environment separation
- Regulatory environments requiring verified rollback
The catch:
You're paying for double the infrastructure. And if green has a subtle bug, 100% of users hit it before you know.
Canary Deployments
You release to a small percentage of users first. Say 5%, then 25%, then 100%.
You're not flipping a switch or performing a hard cutover.
Best for:
- Feature flags and A/B testing
- Performance-sensitive changes
- When you need real traffic to validate behaviour
- High-traffic systems where blast radius matters
The catch:
More complex to implement. Requires solid observability to know when to proceed or rollback.
How to Decide
If the question is "can we roll back instantly?" go with a blue-green setup.
If the question is "will this behave correctly under real load?" then canary deployments with adequate observability is a good strategy.
In practice, mature teams use both. Blue-green for infrastructure changes, canary for application releases.
The worst deployment strategy? A single kubectl apply on a Friday afternoon with no rollback plan.
What deployment strategy is your team running?