KCNA Networking & Service Discovery 5

Question 1

Which component is responsible for watching Service and Endpoints changes and updating node-level routing rules?

Accepted Answer

kube-proxy

Answer

kube-proxy runs on every node, watches the API server for Service and Endpoint changes, and updates iptables or IPVS rules accordingly.

Question 2

In Kubernetes, what is a 'Service Topology' feature used for?

Accepted Answer

Routing Service traffic preferentially to endpoints in the same zone or node

Answer

Service Topology allows traffic to be routed preferentially to endpoints topologically close to the client, such as same-node or same-zone, reducing latency and cross-zone costs.

Question 3

What is the purpose of a NetworkPolicy's 'namespaceSelector'?

Accepted Answer

To allow or deny traffic from pods in specific namespaces

Answer

namespaceSelector in NetworkPolicy ingress/egress rules matches namespaces by label, controlling which namespaces' pods can communicate with the selected pods.

Question 4

Which Service discovery mechanism do pods use by default when environment variable injection is enabled?

Accepted Answer

Environment variables injected at pod start for each active Service

Answer

Kubernetes injects environment variables like _SERVICE_HOST and _SERVICE_PORT into each pod at startup for all Services that existed before the pod.

Question 5

What is the function of the 'targetPort' field in a Service spec?

Accepted Answer

The port on the pod/container that the Service forwards traffic to

Answer

targetPort specifies the actual port on the pod container to which the Service forwards incoming traffic, and can be a number or a named port.

(KCNA) Kubernetes and Cloud Native Associate Practice Test

(KCNA) Kubernetes and Cloud Native Associate Practice Test

KCNA Networking & Service Discovery 5