Author: Zen and the Art of Computer Programming
1 Introduction
Docker is an open source application container engine that makes it easy to package, deploy, and run applications on any infrastructure, including physical machines, virtual machines, or the cloud. Docker packages the application and its dependencies into a portable image, and then this image can run anywhere, which is the so-called "build once, run everywhere" concept. The installation and configuration of Docker is relatively simple and can be completed in a few minutes.
The Docker-based application architecture pattern mainly includes three roles:
User: Developers or operation and maintenance personnel define application components in a containerized environment by writing a Dockerfile, submit it to a remote warehouse, and the user can pull the image through the command line or a graphical interface, and start the container for application development and testing Waiting for work.
Warehouse: A remote warehouse is a file server that stores Docker images. With the help of service providers such as Docker Hub and Alibaba Cloud Warehouse, users can quickly obtain the required images.
Engine: The Docker engine is the core part of the entire Docker, responsible for creating, running and managing Docker containers.
In short, based on Docker, various applications can be effectively packaged, deployed, and run, which effectively reduces the difficulty of environment construction and application migration.
2. Basic Concepts and Terminology of Containers
2.1 What is a container?
A container is a standardized way of packaging an application and all its dependencies together. From a macro point of view, a container is like a lightweight virtual machine, because it does not simulate complete hardware, but only provides necessary resource isolation and security mechanisms, so it can be easily deployed to any platform. From a microscopic point of view, a container consists of an image and a running