What it is: Strategies Route 53 uses to answer DNS queries with the “best” record.

What it’s for: Control how traffic is distributed across endpoints.

Common routing policies (exam staples):

• Simple: single record response.
• Weighted: split traffic by percentage (A/B test).
• Latency-based: route to lowest-latency Region.
• Failover: primary/secondary with health checks.
• Geolocation: route by user location.
• Multi-value: return multiple healthy records.

Exam cues:

• “gradually shift 10% traffic to new version” → Weighted.
• “route users to closest Region” → Latency-based.
• “active-passive DNS failover” → Failover routing policy.

Hard words:

• *weighted* /ˈweɪtɪd/: theo trọng số
• *latency-based* /ˈleɪtənsi beɪst/: dựa trên độ trễ
• *failover* /ˈfeɪlˌoʊvər/: chuyển dự phòng
• *geolocation* /ˌdʒiːoʊloʊˈkeɪʃn/: định vị địa lý
• *gradually* /ˈɡrædʒuəli/: dần dần