The article explores the role of Linux namespaces and control groups (cgroups) in enhancing Docker performance and security. Docker uses these Linux kernel features to isolate system resources and manage resource allocation effectively. Namespaces provide isolation by creating separate environments for processes, ensuring security by preventing interactions between processes in different namespaces. Cgroups, on the other hand, manage system resources by setting limits and priorities for groups of processes, ensuring efficient resource usage. The article demonstrates how to use Docker's user namespace to mitigate security risks by remapping user IDs, and how cgroups can be employed to set CPU and memory limits for Docker containers. By mastering these features, users can optimize Docker performance and ensure the secure and efficient operation of containerized applications.