Docker da thay doi cach chung ta xay dung, phan phoi va chay phan mem. Thay vi "chay duoc tren may cua toi", Docker dam bao rang ung dung cua ban chay giong nhau o moi noi - tren laptop cua ban, tren may cua dong nghiep, trong CI/CD va trong production. Trong huong dan nay, chung ta se di tu con so khong den viec deploy mot ung dung thuc te.

Docker la gi?

Docker la mot nen tang dong goi ung dung cua ban va tat ca cac phu thuoc cua no vao mot don vi chuan hoa goi la container. Container la mot tien trinh co lap, nhe, chia se kernel OS cua may chu nhung co he thong tap tin, mang va khong gian tien trinh rieng.

Container vs May Ao

Khia canh	Container	May Ao
Khoi dong	Giay	Phut
Kich thuoc	MB	GB
OS	Chia se kernel may chu	OS khach day du
Co lap	Cap tien trinh	Cap phan cung
Hieu suat	Gan nhu native	Chi phi tu hypervisor
Mat do	Hang tram moi may chu	Hang chuc moi may chu

Cai dat Docker

# macOS
brew install --cask docker

# Ubuntu/Debian
curl -fsSL https://get.docker.com | sh
sudo usermod -aG docker $USER

# Verify installation
docker --version
docker run hello-world

Cac Khai niem Cot loi

Image

Image la mot template chi doc voi cac huong dan de tao container. Hay nghi ve no nhu mot ban chup nhanh cua ung dung va moi truong cua no.

# Pull an image from Docker Hub
docker pull node:20-alpine

# List local images
docker images

# Remove an image
docker rmi node:20-alpine

Container

Container la mot phien ban dang chay cua mot image. Ban co the tao, khoi dong, dung va xoa container.

# Run a container
docker run -d --name my-app -p 3000:3000 node:20-alpine

# List running containers
docker ps

# List all containers (including stopped)
docker ps -a

# Stop a container
docker stop my-app

# Remove a container
docker rm my-app

# View logs
docker logs my-app

# Execute a command inside a running container
docker exec -it my-app sh

Viet Dockerfile

Dockerfile la mot tap tin van ban voi cac huong dan de xay dung image. Moi huong dan tao mot layer.

Dockerfile Co ban cho Ung dung Node.js

# Use an official Node.js runtime as base image
FROM node:20-alpine

# Set working directory
WORKDIR /app

# Copy package files first (better caching)
COPY package.json package-lock.json ./

# Install dependencies
RUN npm ci --only=production

# Copy application code
COPY . .

# Expose the port the app runs on
EXPOSE 3000

# Command to run the application
CMD ["node", "server.js"]

Build va Chay

# Build the image
docker build -t my-node-app .

# Run the container
docker run -d -p 3000:3000 my-node-app

# Visit http://localhost:3000

Multi-Stage Build

Multi-stage build giu cho image production cua ban nho bang cach tach moi truong build khoi runtime.

# Stage 1: Build
FROM node:20-alpine AS builder
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci
COPY . .
RUN npm run build

# Stage 2: Production
FROM node:20-alpine AS runner
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/package.json ./
EXPOSE 3000
CMD ["node", "dist/server.js"]

Dieu nay tao ra mot image chi chua dau ra da bien dich va cac phu thuoc production - khong co ma nguon, khong co phu thuoc phat trien, khong co cong cu build.

Vi du Multi-Stage cho Next.js

FROM node:20-alpine AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci

FROM node:20-alpine AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
RUN npm run build

FROM node:20-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production
COPY --from=builder /app/public ./public
COPY --from=builder /app/.next/standalone ./
COPY --from=builder /app/.next/static ./.next/static
EXPOSE 3000
CMD ["node", "server.js"]

Volume: Du lieu Ben vung

Mac dinh, du lieu ben trong container se mat khi container bi xoa. Volume giai quyet van de nay.

# Create a named volume
docker volume create my-data

# Run with a volume
docker run -d -v my-data:/app/data my-app

# Bind mount (map host directory to container)
docker run -d -v $(pwd)/data:/app/data my-app

# List volumes
docker volume ls

Mang

Docker tao cac mang co lap de cac container giao tiep voi nhau.

# Create a custom network
docker network create my-network

# Run containers on the same network
docker run -d --name api --network my-network my-api
docker run -d --name db --network my-network postgres:16

# Containers can reach each other by name
# From "api" container: postgres://db:5432

Docker Compose

Docker Compose cho phep ban dinh nghia va chay cac ung dung nhieu container voi mot tap tin YAML duy nhat.

docker-compose.yml

services:
  api:
    build: ./api
    ports:
      - "3000:3000"
    environment:
      - DATABASE_URL=postgres://user:pass@db:5432/mydb
    depends_on:
      - db

  db:
    image: postgres:16-alpine
    environment:
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=pass
      - POSTGRES_DB=mydb
    volumes:
      - pgdata:/var/lib/postgresql/data
    ports:
      - "5432:5432"

  redis:
    image: redis:7-alpine
    ports:
      - "6379:6379"

volumes:
  pgdata:

Cac Lenh

# Start all services
docker compose up -d

# View logs
docker compose logs -f

# Stop all services
docker compose down

# Rebuild and restart
docker compose up -d --build

# Scale a service
docker compose up -d --scale api=3

.dockerignore

Giong nhu .gitignore, tap tin nay ngan cac tap tin khong can thiet bi sao chep vao image.

node_modules
.git
.env
*.md
.next
dist
coverage

Cac Phuong phap Tot nhat cho Production

1. Su dung Image Co so Nho

# Bad: 1GB+
FROM node:20

# Good: ~180MB
FROM node:20-alpine

2. Khong Chay voi Quyen Root

FROM node:20-alpine
RUN addgroup -S app && adduser -S app -G app
USER app
WORKDIR /home/app
COPY --chown=app:app . .

3. Su dung Tag Image Cu the

# Bad: can change unexpectedly
FROM node:latest

# Good: pinned version
FROM node:20.11-alpine3.19

4. Tan dung Build Cache

Sap xep cac huong dan Dockerfile tu it thay doi nhat den thay doi nhieu nhat:

FROM node:20-alpine
WORKDIR /app

# These change rarely - cached
COPY package.json package-lock.json ./
RUN npm ci --only=production

# This changes often - not cached
COPY . .

5. Health Check

HEALTHCHECK --interval=30s --timeout=3s --retries=3 \
  CMD wget -qO- http://localhost:3000/health || exit 1

6. Su dung Bien Moi truong

ENV NODE_ENV=production
ENV PORT=3000

Bang Tham chieu Nhanh cac Lenh Docker Thuong dung

# Images
docker build -t name:tag .        # Build image
docker images                      # List images
docker rmi image_name              # Remove image
docker image prune                 # Remove unused images

# Containers
docker run -d -p 3000:3000 image   # Run detached
docker ps                          # List running
docker stop container_name         # Stop
docker rm container_name           # Remove
docker logs -f container_name      # Follow logs
docker exec -it container sh       # Shell into container

# Compose
docker compose up -d               # Start services
docker compose down                # Stop services
docker compose logs -f             # Follow all logs
docker compose ps                  # List services

# Cleanup
docker system prune -a             # Remove everything unused

Tu Docker den Kubernetes

Docker quan ly cac container rieng le. Khi ban can dieu phoi hang tram container tren nhieu may chu, ban can Kubernetes. Docker va Kubernetes bo sung cho nhau:

1. Docker: xay dung va chay container
2. Kubernetes: dieu phoi container o quy mo lon (lap lich, mo rong, tu phuc hoi)

Neu ban quan tam den buoc tiep theo, hay xem bai viet cua toi ve Gioi thieu Kubernetes.

Ket luan

Docker la mot ky nang co ban cho cac nha phat trien hien dai. No loai bo su khong nhat quan ve moi truong, don gian hoa viec deploy va la nen tang cho viec dieu phoi container voi Kubernetes. Bat dau voi mot Dockerfile don gian, chuyen sang Docker Compose cho cac ung dung nhieu dich vu, va ap dung multi-stage build cung cac phuong phap bao mat tot nhat khi ban phat trien.

Cach tot nhat de hoc Docker la container hoa mot du an ma ban dang lam viec. Hay bat dau ngay hom nay.