Respect My (DNS) Awe-Thor-Ih-TAY!!
Summary
Your cloud is humming along, then an edge breaks. What lever do you actually still have to steer users? In this episode, Carl and Brandon dig into DNS as a control plane and why “it is always DNS” keeps being true in 2025. DNS was designed for a slower internet with long TTLs and infrequent changes, but we now treat it like a real-time steering wheel for global failover. That mismatch shows up in outages where the backend is fine but nobody can resolve the hostname that front doors, CDNs, and APIs live behind. We unpack how TTL and caching really work (including negative caching and serve-stale), why modern edge products like Azure Front Door and Cloudflare can still turn into global single points of failure, and how DNS-based load balancers actually behave when you flip weights or priorities.
From there we move into patterns and mitigations. We walk through hub-and-spoke vs mesh topologies and where public vs private DNS sit in each, plus concrete strategies for what to do when your edge is broken: bypass patterns, equivalent services, and multi-product designs that let you route around a failing front door. We also hit the observability side so “it is DNS” becomes a graph and an alert instead of a guess in a war room. We close with a look at emerging record types like SVCB/HTTPS and how they may help you advertise alternate endpoints and protocol hints without building another fragile tower of CNAMEs.
Links
DNS Fundamentals
- RFC 1034: Domain Names - Concepts and Facilities
- RFC 1035: Domain Names - Implementation and Specification
- RFC 2308: Negative Caching of DNS Queries
- RFC 8767: Serving Stale Data to Improve DNS Resiliency
DNS Load Balancing and Edge Services
- Azure Traffic Manager documentation
- Azure DNS alias records
- Amazon Route 53 health checks and failover
- Cloudflare Load Balancing
- Akamai Global Traffic Management
Azure, AWS, and Cloudflare Outage Reading
- Azure Front Door service documentation
- AWS DynamoDB and Route 53 service health history
- Cloudflare status history