This chapter examines security mechanisms within Kubernetes environments and the architectural controls that protect cluster resources. Security in Kubernetes operates across multiple integrated layers, from access control policies to network isolation to certificate management, each contributing to the overall security posture of deployed applications. We explore how role-based access control (RBAC) governs what users and workloads can access, how service accounts provide identity for applications, and how these systems interact with namespace boundaries and resource management. The relationship between different security components demonstrates that effective protection requires not isolated controls but coordinated strategies that align with operational requirements.