Does docker share the kernel with the host?
Mar 08, 2022 pm 03:22 PM
Docker and the host share the kernel; the Docker container is essentially a process on the host. Docker implements resource isolation through namespace. Docker and the host share the kernel essentially through the kernel's namespace and cgroup. Implemented process isolation.
The operating environment of this tutorial: linux7.3 system, docker-1.13.1 version, Dell G3 computer.
Docker and the host share the kernel
Docker and the host share the kernel
The essence is process isolation achieved through the kernel namespace and cgroup
When talking about Docker, we often talk about the implementation of Docker. Many developers know that Docker containers are essentially processes on the host machine. Docker implements resource isolation through namespace. Resource restrictions are implemented through cgroups, and efficient file operations are implemented through the copy-on-write mechanism. But when going deeper into the technical details such as namespaces and cgroups, most developers will feel at a loss. So here, I will first lead you into the Linux kernel and understand the technical details of namespace and cgroups.
namespace resource isolation
If you want to implement a resource isolation container, where should you start? Some people's first reaction may be the chroot command. The most intuitive feeling given to users by this command is that the mount point of the root directory / is switched after use, that is, the file system is isolated. Next, in order to communicate and locate in a distributed environment, the container must have an independent IP, port, routing, etc., so network isolation naturally comes to mind. At the same time, the container also needs an independent host name to identify itself on the network. When I think of the network, I naturally think of communication, and I also think of the need for isolation of inter-process communication. Developers may also have thought about the issue of permissions. The isolation of users and user groups realizes the isolation of user permissions. Finally, the application running in the container needs to have its own (PID), and naturally needs to be isolated from the PID in the host.
Thus, the six isolations required for a container are basically completed. The Linux kernel provides these six namespace isolation system calls, as shown in Table 1-1.
In fact, one of the main purposes of the Linux kernel implementing namespace is to implement lightweight virtualization (container) services. Processes in the same namespace can sense each other's changes and know nothing about external processes. This can give the process in the container the illusion that it is in an independent system environment, thereby achieving independence and isolation.
Recommended learning: "docker video tutorial"
The above is the detailed content of Does docker share the kernel with the host?. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undress AI Tool
Undress images for free
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
.NET Core Quick Start Tutorial 1. The beginning: Talking about .NET Core
May 07, 2025 pm 04:54 PM
1. The Origin of .NETCore When talking about .NETCore, we must not mention its predecessor .NET. Java was in the limelight at that time, and Microsoft also favored Java. The Java virtual machine on the Windows platform was developed by Microsoft based on JVM standards. It is said to be the best performance Java virtual machine at that time. However, Microsoft has its own little abacus, trying to bundle Java with the Windows platform and add some Windows-specific features. Sun's dissatisfaction with this led to a breakdown of the relationship between the two parties, and Microsoft then launched .NET. .NET has borrowed many features of Java since its inception and gradually surpassed Java in language features and form development. Java in version 1.6
How to develop a complete Python Web application?
May 23, 2025 pm 10:39 PM
To develop a complete Python Web application, follow these steps: 1. Choose the appropriate framework, such as Django or Flask. 2. Integrate databases and use ORMs such as SQLAlchemy. 3. Design the front-end and use Vue or React. 4. Perform the test, use pytest or unittest. 5. Deploy applications, use Docker and platforms such as Heroku or AWS. Through these steps, powerful and efficient web applications can be built.
Docker vs. Kubernetes: Key Differences and Synergies
May 01, 2025 am 12:09 AM
Docker and Kubernetes are leaders in containerization and orchestration. Docker focuses on container lifecycle management and is suitable for small projects; Kubernetes is good at container orchestration and is suitable for large-scale production environments. The combination of the two can improve development and deployment efficiency.
How to view process information inside Docker container
May 19, 2025 pm 09:06 PM
There are three ways to view the process information inside the Docker container: 1. Use the dockertop command to list all processes in the container and display PID, user, command and other information; 2. Use dockerexec to enter the container, and then use the ps or top command to view detailed process information; 3. Use the dockerstats command to display the usage of container resources in real time, and combine dockertop to fully understand the performance of the container.
How to deploy a PyTorch app on Ubuntu
May 29, 2025 pm 11:18 PM
Deploying a PyTorch application on Ubuntu can be done by following the steps: 1. Install Python and pip First, make sure that Python and pip are already installed on your system. You can install them using the following command: sudoaptupdatesudoaptinstallpython3python3-pip2. Create a virtual environment (optional) To isolate your project environment, it is recommended to create a virtual environment: python3-mvenvmyenvsourcemyenv/bin/activatet
Performance Tuning of Jenkins Deployment on Debian
May 28, 2025 pm 04:51 PM
Deploying and tuning Jenkins on Debian is a process involving multiple steps, including installation, configuration, plug-in management, and performance optimization. Here is a detailed guide to help you achieve efficient Jenkins deployment. Installing Jenkins First, make sure your system has a Java environment installed. Jenkins requires a Java runtime environment (JRE) to run properly. sudoaptupdatesudoaptininstallopenjdk-11-jdk Verify that Java installation is successful: java-version Next, add J
Efficient operation method for batch stopping Docker containers
May 19, 2025 pm 09:03 PM
An efficient way to batch stop a Docker container includes using basic commands and tools. 1. Use the dockerstop$(dockerps-q) command and adjust the timeout time, such as dockerstop-t30$(dockerps-q). 2. Use dockerps filtering options, such as dockerstop$(dockerps-q--filter"label=app=web"). 3. Use the DockerCompose command docker-composedown. 4. Write scripts to stop containers in order, such as stopping db, app and web containers.
How to compare the differences in different Docker image versions
May 19, 2025 pm 09:00 PM
There are two ways to compare the differences in different Docker image versions: 1. Use the dockerdiff command to view changes in the container file system; 2. Use the dockerhistory command to view the hierarchy difference in the image building. These methods help to understand and optimize image versioning.
