In-depth discussion of the specific use of Docker kernel

Docker, as a virtualization technology, can run multiple applications on one physical host. These applications are isolated from each other and do not interfere with each other. At the same time, they can also share physical resources to achieve more efficient utilization. The Docker kernel is the core of Docker technology and the key to virtualization of Docker.

In Docker, the kernel is an important concept and has different embodiments in Docker images and containers. This article will focus on the specific use of the Docker kernel.

1. Introduction to Docker kernel

The kernel used in Docker is the Linux kernel. These kernels are generally provided by Unix-like system distributions. The basis for Docker to use the Linux kernel is Linux container (Lxc) technology, and Lxc technology is one of the container implementation methods based on the Linux kernel.

Compared with traditional virtualization technology, Lxc technology is lighter and faster to deploy. In Lxc, applications can run in different user spaces of the same operating system kernel, isolated from each other, and can share the same file system and memory space.

The Docker kernel is an important basic component in Docker, and the implementation of the entire Docker technology also relies on some features in the kernel. The following focuses on some specific uses of the Docker kernel.

2. The main method of using Docker kernel

1. Using Docker image

In Docker technology, the kernel is implemented by using Docker image. Docker image is the basic component in Docker and the building material of Docker container. A Docker image can contain a complete operating system, and the kernel of this operating system is also included.

Therefore, if you want to use the Docker kernel, you need to first build a Docker image containing the Linux kernel, and then build a Docker container based on this image.

2. Configure the kernel parameters of the container

When a Docker container is created, you can control the kernel by configuring the kernel parameters in the container. These parameters can be set using Docker's command line tools or configured in a Dockerfile.

For example, you can control the container's kernel access capabilities by setting the --cap-add and --cap-drop parameters. In addition, the kernel parameters of the Docker container can be set using files in the system file /sys/fs/cgroup/.

3. Mapping the host kernel into the container

In some special cases, users may want to use the host kernel directly. At this time, you can use the --privileged option in the Docker command line to map the kernel in the host to the Docker container.

However, it should be noted that when using this kernel mapping method, special attention needs to be paid to the security of the container to avoid security vulnerabilities.

3. Summary

The Docker kernel is the basic component of the entire Docker technology and an important means for Docker containers to achieve virtualization isolation. By using Docker images, configuring container kernel parameters, and mapping the host kernel to the container, you can achieve flexible and efficient use and control of the Docker kernel.

Of course, to better understand and use the Docker kernel, you need to have a certain grasp and understanding of the basic knowledge of the Linux kernel and operating system.

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