Containerization has revolutionized software deployment and scalability, presenting a lightweight alternative to traditional virtual machines. However, this shift has introduced critical challenges, particularly in kernel resource isolation and security. This review paper delves into the fundamental aspects of kernel resource isolation in containerized environments, analyzing the limitations of current Linux mechanisms such as namespaces, Cgroups, and Linux security modules in safeguarding resources effectively. The review also examines evolving security threats, including kernel exploits and privilege escalation attacks, exacerbated by the kernel-sharing model in container systems. To address these vulnerabilities, the paper explores recent advancements in kernel hardening, including extended Berkeley Packet Filter, Unikernels, and container-specific LSMs, which aim to strengthen the security perimeter of the kernel. Additionally, emerging trends in container security are discussed, with a focus on hardware-based security integration, enhanced access control granularity, and the application of machine learning for proactive threat detection. By synthesizing current research and development trends, this review highlights promising directions and potential strategies for reinforcing kernel resource isolation, ultimately contributing to a more secure containerized infrastructure.