Kubernetes Live Replication with Traffic Split

Use case

• Category: Kubernetes-to-Kubernetes migration
• State profile: Stateful or mixed critical workloads
• Approach: Live replication plus staged traffic split

Mandatory prerequisites

• Replication path validated: Data replication pipeline supports target RPO/RTO.
• Traffic engineering available: DNS, ingress, service mesh, or gateway supports weighted routing.
• Dual-run operations model ready: Ownership, monitoring, and incident playbooks exist for parallel runtime.
• Rollback trigger policy approved: Quantitative rollback thresholds are agreed before migration.

Not suitable when

• Replication lag cannot be controlled: Freshness objectives cannot be met.
• No progressive traffic control exists: Cutover can only happen as full switch.

Implementation template

Phase 1: Establish dual-run baseline

1. Deploy target stack and validate health without production traffic.
2. Start replication pipeline and verify lag metrics.
3. Align alerting and SLO monitoring across source and target.

Phase 2: Progressive traffic split

1. Shift low percentage traffic to target and observe error/latency budgets.
2. Increase traffic in controlled increments after each validation gate.
3. Keep source active until final confidence threshold is reached.

Phase 3: Final switch and cleanup

1. Complete full traffic move to target.
2. Continue elevated monitoring through stabilization window.
3. Decommission source path after sign-off and evidence archive.

Validation checklist

• Replication health: Lag and replay status within defined limits.
• Traffic quality: Error rate and latency stable at each split stage.
• Business continuity: Critical user journeys remain uninterrupted.
• Rollback readiness: Reverse split can run within agreed time.