A Quick Guide for Developers to Install and Use Docker: From Hello World to MySQL and Custom Images

Preface

Docker is the most widely used container technology today; while operations teams usually manage it in production, developers also need to understand its basics. This article provides a concise Docker cheat‑sheet for developers.

Concepts

The three key Docker concepts are:

Image : a packaged filesystem containing the JDK, application JAR, etc., similar to a system reinstall image.

Container : an instantiated image that runs as a lightweight Linux environment with its own process, user, and network spaces.

Repository : a storage location for images (e.g., Docker Hub).

Typical workflow: docker pull to fetch an image, docker run to start a container, and docker build to create your own image.

1. Connect to Linux

# ssh username@ip_address
chaitous-Mac-mini:~ chaitou$ ssh [email protected]
[email protected]'s password: 
Welcome to Ubuntu 16.04.1 LTS (GNU/Linux 4.4.0-157-generic x86_64)

# If connection fails, clear old keys:
# ssh-keygen -R 148.70.139.121

2. Install Docker

# Switch to root
sudo su

# Update apt
apt-get update

# Install Docker
apt-get install -y docker.io

# Verify version
docker version

# Start service (if needed)
service docker start

# Verify client and server versions
docker version

3. First Docker Image – Hello World

Steps:

Pull the image.

List local images.

Run the container.

# Pull image
docker pull hello-world

# List images
docker images

# Run container
docker run hello-world

The output confirms a successful installation.

Configure Accelerator

Because Docker Hub is overseas, you may configure the Alibaba Cloud mirror:

https://cr.console.aliyun.com/

4. Run Nginx

# Pull nginx image
docker pull nginx

# List images
docker images

Running Modes

Foreground (blocks terminal) vs. background (detached) mode. Use -d for detached:

# Foreground
docker run nginx

# Detached
docker run -d nginx

Network

Containers communicate through the host network. Three modes exist: Bridge, Host, and None. The Bridge mode is most common and uses -p hostPort:containerPort to map ports.

# Bridge mode example
docker run -d -p 8080:80 nginx

Access the service at http://<em>host_ip</em>:8080.

Random Port (-P)

# Random host port mapping
docker run -d -P nginx

5. Run MySQL

Deploy MySQL with a single command, mapping port 3306 and setting root password and database name:

docker pull mysql

docker run -d -p 3306:3306 -e MYSQL_ROOT_PASSWORD=leilema -e MYSQL_DATABASE=leilema mysql:latest

Connect with any MySQL client (e.g., Navicat). To stop and remove:

# Stop container
docker stop <em>container_id</em>

# Remove image
docker rmi image[:tag]

Error Handling (Enter Container)

For error

Authentication plugin 'caching_sha2_password' cannot be loaded

, enter the container and run:

ALTER USER 'root' IDENTIFIED WITH mysql_native_password BY 'leilema';

Enter the container with:

# List containers
docker ps

# Exec shell
docker exec -it <em>container_id</em> bash

6. Build Your Own Image

Two steps: write a Dockerfile and build it with docker build.

Dockerfile Example (Spring Boot)

# Base image
FROM java:8

# Maintainer
MAINTAINER bugpool [email protected]

# Copy JAR
COPY hello-springboot.jar /hello-springboot.jar

# Entry point
ENTRYPOINT ["java", "-jar", "/hello-springboot.jar"]

Build and Run

# Pull base image
docker pull java:8

# Build custom image
docker build -t hello-springboot:1.0 .

# Run, mapping host 80 to container 8081
docker run -p 80:8081 hello-springboot:1.0

Visit http://<em>host_ip</em>/hello to verify the application is running.

Original source: bugpool.blog.csdn.net/article/details/105467335