Certified Kubernetes Application Developer (CKAD) Practice Test

What is the primary function of a network policy in Kubernetes?

1. To ensure traffic is routed between nodes and services

2. To enforce security protocols for API access

3. To manage the lifecycle of applications in the cluster

4. To ensure traffic is routed between nodes and pods as expected

The correct answer is: To ensure traffic is routed between nodes and pods as expected

The primary function of a network policy in Kubernetes is to control the communication between pods within a cluster. Network policies define rules that specify how groups of pods can communicate with each other and with other network endpoints, providing a way to enforce security and restrict access based on these rules. In Kubernetes, without a network policy, all pods within a namespace can communicate freely, which may lead to security vulnerabilities in multi-tenant environments. By implementing network policies, developers can specify which pods can send and receive traffic from one another. This is crucial for preventing unwanted access and ensuring that only the intended communications occur, thus safeguarding sensitive data and application integrity. The correct option emphasizes how network policies facilitate expected routing behavior between nodes and pods, ensuring that traffic flows according to defined rules that enhance security and segmentation within the cluster. This is a core aspect of managing Kubernetes networking, aligning with the principles of microservices architecture and enabling fine-grained control over network communications.