Discuss Linux Foundation KCNA Exam Topic 5 Question 74

What is the main role of the Kubernetes DNS within a cluster?

AActs as a DNS server for virtual machines that are running outside the cluster.

BProvides a DNS as a Service, allowing users to create zones and registries for domains that they own.

CAllows Pods running in dual stack to convert IPv6 calls into IPv4 calls.

DProvides consistent DNS names for Pods and Services for workloads that need to communicate with each other.

Suggested Answer: D

Kubernetes DNS (commonly implemented by CoreDNS) provides service discovery inside the cluster by assigning stable, consistent DNS names to Services and (optionally) Pods, which makes D correct. In a Kubernetes environment, Pods are ephemeral---IP addresses can change when Pods restart or move between nodes. DNS-based discovery allows applications to communicate using stable names rather than hardcoded IPs.

For Services, Kubernetes creates DNS records like service-name.namespace.svc.cluster.local, which resolve to the Service's virtual IP (ClusterIP) or, for headless Services, to the set of Pod endpoints. This supports both load-balanced communication (standard Service) and per-Pod addressing (headless Service, commonly used with StatefulSets). Kubernetes DNS is therefore a core building block that enables microservices to locate each other reliably.

Option A is not Kubernetes DNS's purpose; it serves cluster workloads rather than external VMs. Option B describes a managed DNS hosting product (creating zones/registries), which is outside the scope of cluster DNS. Option C describes protocol translation, which is not the role of DNS. Dual-stack support relates to IP families and networking configuration, not DNS translating IPv6 to IPv4.

In day-to-day Kubernetes operations, DNS reliability impacts everything: if DNS is unhealthy, Pods may fail to resolve Services, causing cascading outages. That's why CoreDNS is typically deployed as a highly available add-on in kube-system, and why DNS caching and scaling are important for large clusters.

So the correct statement is D: Kubernetes DNS provides consistent DNS names so workloads can communicate reliably.

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26 comments · newest first

Felix 2 months ago

But without D, Pods can't find each other easily. That's a big issue!

Beth 2 months ago

I’m leaning towards C. Dual stack support is important too.

Odette 2 months ago

Agreed! D makes sense. Consistent names are key in clusters.

Cammy 3 months ago

I think D is the right answer. It’s crucial for Pods to communicate.

Bettye 3 months ago

But without D, Pods can't communicate effectively. That's key!

Fletcher 3 months ago

I’m leaning towards C. Dual stack support is important too.

James 3 months ago

Agreed! D makes sense. It helps with service discovery.

Reita 3 months ago

I think D is the best answer. Consistent DNS names are crucial for Pods.

Ronny 3 months ago

Definitely D. Without it, managing services would be chaotic!

Rolande 4 months ago

I’m leaning towards D too. It simplifies service discovery.

Denna 4 months ago

Agreed! D makes sense. Pods need stable names to connect.

Dawne 4 months ago

I think the answer is D. It's crucial for communication in the cluster.

Ty 4 months ago

Yup, D is crucial for service discovery in Kubernetes!

Elvera 4 months ago

I disagree, B is more about external DNS, not cluster communication.

Kristin 6 months ago

Wait, does Kubernetes DNS really handle dual stack? That's wild!

Jerry 6 months ago

I thought it was A at first, but D makes more sense.

Catina 6 months ago

D is definitely the right answer!

Lazaro 6 months ago

Yup, D is crucial for service discovery in Kubernetes!

Chantell 6 months ago

I disagree, B is more about external DNS, not cluster communication.

Kanisha 7 months ago

Wait, does Kubernetes DNS really handle dual stack? That's wild!

Chandra 7 months ago

I thought it was A at first, but D makes more sense.

Coleen 7 months ago

D is definitely the right answer!

Ines 7 months ago

I vaguely recall that Kubernetes DNS helps with service discovery within the cluster, so I think option D makes the most sense.

Bev 7 months ago

I feel like I might be mixing up the roles of DNS in Kubernetes with something else. Wasn't there a question about external DNS servers too?

Gabriele 8 months ago

I remember practicing a question about DNS in Kubernetes, and I think it was about providing consistent names for services. That sounds like option D.

Hana 8 months ago

I think the main role of Kubernetes DNS is related to how Pods and Services communicate, but I'm not entirely sure which option that is.

Linux Foundation KCNA Exam - Topic 5 Question 74 Discussion