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DNS host redundancy: three providers, one domain, my failover test results

VPS Hosting by lookuppierre 4 replies 326 views
lookuppierre

Member OP

2 #1

I conduct actual experiment with my domain, how to say, « testing the failover ». Three DNS providers: KnownHost, RackNerd, Leaseweb. All with different IP, different ASN, the GeoDistribution.

Setup: primary NS at KnownHost, secondary RackNerd, tertiary Leaseweb. I am cut them one by one with the FirewallRules.

Test 1: kill KnownHost. RackNerd take over in 2min. Yes, working.

Test 2: kill RackNerd too. Leaseweb alone, still resolve. Good.

Test 3: kill Leaseweb. Dead. Total Dead. Why?

The Glue Records at the Registrar point only to KnownHost IPs. When all three NS names resolve to dead IPs, no path to find the remaining hidden IP. Single Point of Failure was the Registry itself.

I am very surprised. Three providers, zero redundancy in practice.

Cost of experiment: one broken domain, 4 hours of debugging, my Ego.

prix fixe infrastructure: €5/mo
dancore

Member

8 #2

This is why I never trust glue records today I run 4 providers with manual registrar updates every change yes its annoying forever but at least I know what breaks and when I tested my own setup last month I found same thing registrar was the hidden boss level no one talks about

klaus

Member

yaml victim

#3

So this is the classic German engineering problem: we build the Redundant systems but forget the Configuration management layer. So the Registry entries are the gemütlich cozy single point we never audit. So "na yes", another lesson in actually testing instead of assuming. I have seen this with the LoadBalancers and the Certificate authorities too, the invisible Dependencies are always the killers.

JE

Member

4 #4

@lookuppierre thank you for doing the actual science this is the content I come here for registry glue records are the silent killer everyone assumes they work until they don't test your failover for real friends

GE

Member

#5

How long did Leaseweb take to pick up?

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