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November 2025

Kubernetes Services: Exposing Your Applications

Kubernetes Services are the cornerstone of networking in modern containerized applications. They provide stable, reliable access to dynamic sets of Pods, abstracting away the complexity of Pod IP management and enabling seamless communication between application components. For anyone preparing for the Certified Kubernetes Administrator (CKA) exam, mastering Services is essential—they represent 20% of the exam's Services & Networking domain.

In this comprehensive guide, we'll explore how Services work, when to use each type, and the practical kubectl commands you need to succeed in both the exam and production environments.

Persistent Volumes and Claims: Stateful Storage

Kubernetes excels at managing stateless applications, but production reality demands stateful workloads—databases, message queues, file storage systems. PersistentVolumes (PV) and PersistentVolumeClaims (PVC) provide the abstraction layer that makes stateful storage portable, durable, and manageable across cluster infrastructure. For the CKA exam, mastering storage represents 10% of your score and is essential for real-world Kubernetes administration.

The storage model in Kubernetes separates provisioning (administrator responsibility via PV) from consumption (developer responsibility via PVC). This decoupling enables platform teams to standardize storage offerings through StorageClasses while application teams request storage without infrastructure knowledge. Understanding the PV lifecycle—binding, mounting, releasing, and reclaiming—is critical for both exam success and production troubleshooting.

Modern Kubernetes storage leverages the Container Storage Interface (CSI), which replaced legacy in-tree volume plugins. CSI drivers from AWS, Google Cloud, Azure, NetApp, and others provide production-grade dynamic provisioning. The 2025 Kubernetes landscape includes ReadWriteOncePod access mode (v1.29+), enhanced volume expansion capabilities, and topology-aware scheduling via WaitForFirstConsumer binding mode.

Security Contexts and Pod Security Standards

Harden workloads with Linux security mechanisms and enforce cluster-wide security policies

Security Contexts define privilege and access control settings for Pods and containers, leveraging Linux kernel security features like capabilities, SELinux, AppArmor, and seccomp. Pod Security Standards (PSS) provide a framework for enforcing security best practices across your cluster. For the CKA exam, you'll need to configure SecurityContext fields, apply Pod Security admission policies, troubleshoot permission issues, and understand how privileged workloads differ from restricted ones. This guide covers everything from basic runAsUser configuration to advanced seccomp profiles and cluster-wide policy enforcement.

CKA Exam Relevance: Cluster Architecture, Installation & Configuration (25% of exam weight)