Docker Tutorial

Docker is an open-source application container engine, based onGo Languageand is open-sourced under the Apache 2.0 license.

Docker allows developers to package their applications and dependencies into a lightweight, portable container, which can then be distributed to any popular Linux machine, also enabling virtualization.

Containers fully use a sandbox mechanism, with no interfaces between them (similar to iPhone apps). More importantly, containers have extremely low performance overhead.

After version 17.03, Docker is divided into CE (Community Edition) and EE (Enterprise Edition). We can just use the Community Edition.

Who is this tutorial for?

This tutorial is suitable for operations engineers and backend developers. Through this tutorial, you can learn how to use Docker step by step.

Knowledge you need before reading this tutorial

Before reading this tutorial, you need to master common Linux commands. You can use this website'sLinux TutorialCome learn related commands.

Docker application scenarios

Microservices architecture:Each service is independently containerized, making it easy to manage and scale.
CI/CD pipeline:Integrates with Jenkins/GitLab CI to enable automated builds and testing.
Standardized development environment:New members can launch the full set of dependent services (such as databases, message queues) with one click.
Cloud-native fundamentals:Orchestration tools such as Kubernetes manage container clusters based on Docker.

Core Advantages

Cross-platform consistency:Solves the "it works on my machine" problem, ensuring consistency across development, testing, and production environments.
Resource Efficiency:Containers directly share the host kernel, eliminating the need to virtualize the entire operating system, saving memory and CPU.
Fast Deployment:Containers start in seconds, supporting automated scaling and shrinking.
Isolation:Each container has its own independent file system, network, and process space.

Core Concepts

Container:Lightweight runtime instances, containing application code, runtime environment, and dependency libraries. Created based on images, isolated from other containers, sharing the host OS kernel (more efficient than virtual machines).
Image:Read-only template, defining the container's runtime environment (such as operating system, software configuration, etc.). Uses layered storage (Layer) to optimize space and build speed.
Dockerfile：A text file describing how to automatically build images (for example, specifying a base image, installing software, copying files, etc.).
Registry:A platform for storing and distributing images, such as Docker Hub (official public repository) or private repositories (such as Harbor).

Basic Commands

Example

# Pull the image (e.g., official Nginx image)
docker pull nginx

# Run the container (-d run in background, -p map ports)
docker run -d -p 80:80 nginx

# List running containers
docker ps

# Build the image (based on the Dockerfile in the current directory)
docker build -t my-app .

# Enter the container
docker exec -it <Container ID> /bin/bash