How Docker Shares Kernel

Docker is a containerization platform that enables running applications in isolated environments. Containers in Docker share the underlying host operating system’s kernel, making them lightweight and efficient.

The mechanism behind Docker’s kernel sharing is based on Linux kernel features like namespaces and cgroups. Namespaces provide containers with their own view of the filesystem, network, and process table. Cgroups help limit CPU, memory, and disk resources for each container.

Upon creation, Docker assigns unique namespaces to containers for filesystem, network, and process table, isolating them from the host OS and other containers. Cgroups ensure resource limitations to prevent excessive resource consumption.

Kernel sharing in Docker contributes to its lightweight and efficient nature. Multiple containers can run on a single host OS without compromising performance.

Benefits of Docker Kernel Sharing

  • Lightweight: Shared kernel reduces resource requirements, leading to hardware cost savings.
  • Efficient: Container isolation minimizes conflicts and resource contention, enhancing application performance.
  • Portable: Docker containers can run on any OS with Docker, simplifying application deployment.

Drawbacks of Docker Kernel Sharing

  • Security: Kernel sharing means a vulnerability in one container can impact others on the host.
  • Updates: Host OS updates require updating all Docker containers, which can be time-consuming.
  • Performance: Running numerous containers may affect the host OS performance.


Docker’s kernel sharing feature is crucial, allowing multiple containers on a single host OS without performance degradation. However, it’s essential to consider drawbacks like security vulnerabilities and performance impact. Evaluating the pros and cons of Docker kernel sharing is crucial for informed decision-making in production environments.