This chapter provides a comprehensive guide to enhancing the security posture of Kubernetes environments. It covers a wide array of security practices designed to protect workloads, sensitive data, and network communications within the Kubernetes cluster. The goal is to equip readers with practical knowledge to secure Kubernetes across various levels, from managing secrets and container-level security to implementing advanced access control mechanisms and securing service meshes. This chapter also delves into service mesh architectures, with a particular focus on Istio, a popular service mesh solution. By the end of the chapter, readers will gain a holistic understanding of how to manage and improve security in a Kubernetes-based system, including best practices for deploying and managing service meshes.