Docker Installation, Usage, and Image Customization Guide

Docker is a revolutionary open‑source platform that greatly improves application deployment, testing, and distribution efficiency by leveraging container virtualization.

System requirements : Docker CE requires a 64‑bit Ubuntu version (Artful 17.10, Zesty 17.04, Xenial 16.04 LTS, Trusty 14.04 LTS) and supports architectures such as x86_64, armhf, s390x, and ppc64le.

Uninstall old versions (docker, docker‑engine): apt-get remove docker docker-engine Install Docker CE via repository :

apt-get update

apt-get install apt-transport-https ca-certificates curl software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

apt-get update && apt-get install docker-ce

Verify the installation with the test image: docker run hello-world The command pulls the hello-world:latest image, runs a container, and prints a success message.

Manage Docker as a non‑root user :

sudo groupadd docker

sudo usermod -aG docker $USER

Log out and back in, then you can run Docker commands without sudo: docker run hello-world Uninstall Docker CE :

sudo apt-get purge docker-ce

sudo rm -rf /var/lib/docker

Customize images with docker commit :

docker run --name myweb -d -p 80:80 nginx

docker exec -it myweb bash

echo '<h1>Welcome to Docker!</h1>' > /usr/share/nginx/html/index.html

docker commit --author "penglei <[email protected]>" --message "Modified default page" myweb nginx:v2

View the new image with docker image ls and its history with docker history nginx:v2.

Dockerfile‑based image building provides reproducible, layered images. A simple Dockerfile:

FROM nginx
RUN echo '<h1>Hello, Docker!</h1>' > /usr/share/nginx/html/index.html

The FROM instruction selects the base image (e.g., an official image or scratch for an empty base). The RUN instruction executes commands; multiple commands should be combined with && in a single RUN to minimize layers and keep images lean.

Build the image: docker build -t nginx:v3 . The build output shows each step, the intermediate container IDs, and the final image ID.

Advanced docker build usage includes building directly from a Git repository, a tarball URL, or standard input streams, allowing flexible CI/CD pipelines.

References: "Docker – From Beginner to Practice" and Docker official installation guide for Ubuntu.