Linux Foundation Updated Cilium-Associate Exam Questions and Answers by safiyyah

Technical explanation

Cluster Mesh extends Cilium’s identity-aware networking and policy enforcement across connected Kubernetes clusters. A CiliumNetworkPolicy can authorize communication with workloads in a particular remote cluster by selecting their workload labels together with the synthetic io.cilium.k8s.policy.cluster label. Therefore, A accurately describes a direct network-policy function.

The policies themselves are not automatically copied between clusters. Administrators remain responsible for applying the required policy resources in the appropriate clusters, but enforcement can select and govern remote endpoints once Cluster Mesh has propagated their identities.

Option B confuses authorization with transport encryption. WireGuard or IPsec configuration enables transparent encryption; it is not established by a network-policy rule. Option C is also separate from policy enforcement: cross-cluster load balancing is configured through global-service facilities and service annotations, not through CiliumNetworkPolicy . Option D is incorrect under current documentation because Cilium mutual authentication does not provide a single trust domain spanning Cluster Mesh clusters and is not presently compatible with that multi-cluster arrangement.

Official references

Cluster Mesh Network Policy , Cluster Mesh Services , Mutual Authentication Limitations

Study Guide topic: Cross-cluster identity, endpoint selection, and policy enforcement.

Technical explanation

The policy attaches an HTTP Layer 7 rule to port 80 but omits protocol: TCP from the associated ports entry. HTTP policy is layered on a Layer 4 TCP rule, and the documented Cilium form explicitly identifies TCP before specifying the HTTP method and path. D therefore identifies the configuration defect intended by the question.

The cross-namespace source selection is valid. The policy resides in namespace back and selects backend pods there. Its fromEndpoints selector explicitly includes k8s:io.kubernetes.pod.namespace: blog , allowing it to select matching app-frontend endpoints in that other namespace. Option A is consequently not an error.

The k8s: source prefix in k8s:app.kubernetes.io/name is also valid Cilium label syntax and identifies the Kubernetes label source, making B false. Port 80 may be used in a Cilium policy; the privileged-port restriction concerns which processes may bind low-numbered ports under operating-system permissions, not whether a network policy can reference them.

The corrected port entry should contain port: "80" together with protocol: TCP .

Official references

Cilium Layer 7 Policies , Kubernetes Constructs in Cilium Policy

Study Guide topic: Combining Layer 4 port rules with Layer 7 HTTP policies.

Technical explanation

Policy Audit Mode allows administrators to evaluate the consequences of network policies before enforcing their deny decisions. Traffic that would ordinarily be rejected remains permitted, while Cilium records an audit verdict. These verdicts can be examined with Cilium monitoring tools and used to identify legitimate communications that are missing from the proposed policies.

This is especially valuable when introducing host policies or default-deny controls into an existing environment. An incomplete policy might otherwise block access to the Kubernetes API, node-management interfaces, DNS, monitoring systems, or other operational dependencies. The recommended workflow is to enable audit mode, observe traffic and policy verdicts, adjust the rules, confirm that all required communications receive allow verdicts, and then disable audit mode to begin enforcement.

DNS enforcement mode and HTTP audit mode are not the general Cilium configuration requested. “Policy enforcement mode” describes whether policies are normally enforced, but it does not provide the non-disruptive learning behavior in the question.

Audit mode should be treated as a temporary validation mechanism because it does not actually block disallowed traffic and does not persist across every agent-restart scenario.

Official references

Cilium Policy Audit Mode

Study Guide topic: Policy validation, audit verdicts, and safe policy rollout.