Kubernetes DNS redundancy

What this Scenario does

This Scenario blocks DNS traffic within your Kubernetes pods, simulating a primary DNS provider failure. This tests whether your Kubernetes DNS configuration—including CoreDNS and any external DNS providers—correctly handles failover.

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Why run this Scenario?

DNS can fail in many ways, including:

• Failures in nameservers and/or recursive resolvers, causing DNS queries to time out or return errors.
• Network saturation (or a DDoS attack) slowing down DNS queries or causing them to drop.
• Misconfigured Quality of Service (QoS) rules, causing the network to de-prioritize DNS traffic.

Running this Scenario can help:

• Verify that Kubernetes CoreDNS or kube-dns handles upstream DNS failures gracefully.
• Validate that Kubernetes service discovery continues working when external DNS providers fail.
• Test DNS policy and dnsConfig settings across your pods for resilience.
• Ensure that DNS failures don't cascade into pod-to-pod or pod-to-service communication outages.

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Expected outcome

If the primary DNS provider fails, Kubernetes services continue resolving DNS queries through secondary providers with no interruption.