Configuring DNS Failover
How Edge DNS handles routing and failover — what works today, what doesn't yet, and practical workarounds for high availability.
What DNS failover is
DNS failover means automatically switching users to a backup server when the primary goes down. In an ideal setup, a health check detects failure, DNS stops returning the failed server's IP, and clients resolve to a healthy backup. Users get continuity without manual intervention.
Edge DNS geo-routing
Edge DNS supports geo-routing: routing different users to different servers based on their location. This works today. You can return IP A for users in Europe and IP B for users in the Americas, for example. Useful for multi-region deployments where you want users to hit the nearest origin.
Configure geo-routing in the control panel or via the API. Add A (or AAAA) records with geographic filters and specify which regions resolve to which IPs.
Multiple A records for round-robin
You can add multiple A records for the same hostname. Resolvers typically round-robin between them. This distributes load across several servers but does not provide automatic failover: if one IP is down, clients may still be directed to it. DNS does not remove unhealthy IPs automatically.
Monitoring DNS with Edge metrics
Edge provides DNS metrics: query volume, response times, and resolution data. Use these to monitor DNS health and spot anomalies. They complement application-level monitoring but do not replace health checks for failover logic.
Health-check-based failover: not yet implemented
Important: Edge DNS does not yet support health-check-based automatic failover. The system does not detect when a server is down and remove it from DNS responses. If you add multiple A records, they remain in the rotation regardless of server health.
Workarounds:
- External monitoring + API updates — Use an external monitoring service (e.g. UptimeRobot, Pingdom) to check your endpoints. When a failure is detected, call the Edge API to update DNS records — for example, remove the failed IP or add a CNAME to a backup. Requires automation (a script or Lambda) and API access.
- CDN as a resilient layer — Put Edge CDN in front of your origin. The CDN caches static content and can fail over to a backup origin if configured. For dynamic content, origin health still matters, but the CDN adds redundancy for cached responses.
- Manual failover — The control panel and CLI always allow manual record updates. For planned maintenance or known outages, switch records manually. Not automated, but reliable.