Networking & Service Discovery Flashcards

Which Kubernetes Service type creates an external load balancer in cloud environments?

Answer: LoadBalancer

The LoadBalancer Service type provisions an external cloud load balancer that routes traffic to the backend pods.

What does a headless Service (ClusterIP: None) return when queried via DNS?

Answer: Individual pod IP addresses as DNS A records

Headless Services bypass kube-proxy and return the individual pod IPs directly as DNS A records, enabling direct pod addressing.

Which field in a NetworkPolicy spec restricts which pods can initiate connections TO the selected pods?

Answer: ingress

The ingress field defines rules for inbound traffic to the selected pods, specifying allowed sources.

In Kubernetes DNS, what is the fully qualified domain name for a Service named 'db' in namespace 'prod'?

Answer: db.prod.svc.cluster.local

Kubernetes DNS follows the pattern ..svc., defaulting to cluster.local.

What is the purpose of kube-proxy in a Kubernetes cluster?

Answer: To maintain iptables/IPVS rules that implement Service virtual IPs

kube-proxy watches the API server and programs iptables or IPVS rules on each node to forward traffic destined for Service ClusterIPs to backend pods.

Which annotation is commonly used to specify an Ingress controller class when multiple controllers exist?

Answer: kubernetes.io/ingress.class

The kubernetes.io/ingress.class annotation (or the newer IngressClassName field) tells Kubernetes which controller should handle a given Ingress resource.

What happens to existing connections when a pod backing a Service is deleted?

Answer: Existing connections may be terminated depending on the protocol and graceful termination period

When a pod is deleted, kube-proxy removes it from endpoints, but already-established TCP connections may be reset depending on the termination grace period and connection tracking.