Screening Mid Level

Compare blue-green, canary, and rolling deployment strategies. How do you choose the right one for a given service?

Quick Tip

Match strategy to risk: canary for critical user-facing services, rolling for internal services, blue-green when you need instant rollback. The choice depends on your risk tolerance and infrastructure budget.

What good answers include

Strong answers explain each strategy and when to use it: blue-green for instant rollback but double infrastructure cost, canary for gradual traffic shifting with early feedback, and rolling for resource-efficient updates. Best candidates discuss the prerequisites (observability, traffic routing, health checks) and how deployment strategy relates to service criticality and risk tolerance.

What interviewers are looking for

Fundamental DevOps knowledge. Candidates who deploy everything the same way are not thinking about risk. Those who choose deployment strategies based on service characteristics demonstrate operational maturity.

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