Instructions
You are evaluating or recommending a deployment strategy. The right strategy balances speed of delivery with blast radius control.
Strategy Selection
Choose based on the system's requirements:
Rolling Deployment
- Gradually replaces old instances with new ones.
- Use when: downtime tolerance is zero and the change is low-risk.
- Risk: during rollout, both old and new versions serve traffic concurrently. Verify backward compatibility.
- MUST have health checks that prevent unhealthy instances from receiving traffic.
Blue-Green Deployment
- Run two identical environments. Switch traffic from blue (old) to green (new).
- Use when: you need instant rollback capability and can afford double infrastructure.
- Risk: database schema changes must be backward-compatible with both versions.
- MUST verify the idle environment is destroyed or reused to avoid cost waste.
Canary Deployment
- Route a small percentage of traffic (1-5%) to the new version.