DNS-Based Load Balancing

Round-robin, weighted.

Overview

DNS-based load balancing distributes traffic across endpoints by returning different addresses to different clients. The four policies below cover most real-world distribution needs and pick the right one for the workload at hand.

• Round-robin. Cycle through the target list. Simple and predictable for evenly-sized targets.
• Weighted. Per-target weights. Used for canaries: 5 percent to a new endpoint, 95 percent to the stable one.
• Latency-based. Nearest target by measured network latency. The default for global user populations.
• Geo-based with health-aware failover. Routes by client country and skips unhealthy targets automatically. Compliance-friendly and resilient.

The approach

Three habits keep DNS load balancing operationally sound: short TTLs to enable fast changes, latency-based as the default policy, and explicit weights for canary rollouts.

• 60-second TTL. Long TTLs mean changes propagate slowly during incidents. 60 seconds is the right floor for production traffic.
• Latency-based default. Most workloads benefit from nearest-target routing without operator effort.
• Weighted for canaries. 5 percent to canary, 95 percent to stable. Canary unhealthy? Drop the weight to zero in seconds.
• Health checks integrated and documented. Unhealthy targets are removed automatically. Each zone’s policy and rationale lives in the runbook.

Why this compounds

The first DNS load-balancing policy teaches the team how the trade-off between latency, weight, and health behaves at their scale. Subsequent policies reuse the framework.

• Global performance. Latency-based routing produces measurable improvements for global users without per-region work.
• Incident-time tuning. Weighted policies make traffic shifts a config change, not a deploy.
• Compliance fit. Geo-based routing satisfies data-residency requirements that pure global policies cannot.
• Year-one investment, year-two habit. The first policy takes a sprint. The fourth uses the same patterns with new numbers.