帶你將 Node.js Web App 給 Docker 化，並用 Kubernetes 部署的超簡單範例

# 安裝 kubectl
brew install kubectl
# 確認是否安裝成功
kubectl version --client
# 查看目前 cluster 運行狀態
kubectl get all

# 安裝 minikube
brew install minikube
# 啟動 minikube，啟動 k8s cluster
minikube start
# 查看 minikube 狀態
minikube status
# 取得目前 minikube 的 IP address
minikube ip

{
  "name": "docker_web_app",
  "version": "1.0.0",
  "description": "Node.js on Docker",
  "author": "Dean Lin",
  "main": "server.js",
  "scripts": {
    "start": "node server.js"
  },
  "dependencies": {
    "express": "^4.17.2"
  }
}

"use strict";

const express = require("express");

// Constants
const PORT = 8080;
const HOST = "0.0.0.0";

// App
const app = express();
app.get("/", (req, res) => {
  res.send("Hello World");
});

app.listen(PORT, HOST);
console.log(`Running on http://${HOST}:${PORT}`);

FROM node:14

# Create app directory
WORKDIR /usr/src/app

# Install app dependencies
# A wildcard is used to ensure both package.json AND package-lock.json are copied
# where available (npm@5+)
COPY package*.json ./

RUN npm install
# If you are building your code for production
# RUN npm ci --only=production

# Bundle app source
COPY . .

EXPOSE 8080
CMD [ "node", "server.js" ]

# 登入 Docker
docker login
# ！如果 Docker app沒有開啟就執行下面步驟會報錯！
# 建立 Docker Image
docker build . -t <your username>/node-web-app
# 筆者範例指令
docker build . -t babydragon9703111/node-web-app

docker images

# 裡面填寫的 port 是本地端要跑的（對外 port）
docker run -p [port]:8080 -d <your username>/node-web-app
# 筆者範例指令
docker run -p 8080:8080 -d babydragon9703111/node-web-app

# Get container ID
docker ps

# Print app output
docker logs <container id>

apiVersion: v1
kind: Service
metadata:
  name: node-app-service
spec:
  selector:
    app: node-web-app
  ports:
    - protocol: "TCP"
      port: 8080
      targetPort: 8080
  type: LoadBalancer

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: node-web-app
spec:
  selector:
    matchLabels:
      app: node-web-app
  replicas: 3
  template:
    metadata:
      labels:
        app: node-web-app
    spec:
      containers:
        - name: node-web-app
          image: babydragon9703111/node-web-app:latest
          imagePullPolicy: Always
          ports:
            - containerPort: 8080

# 啟動 k8s cluster
minikube start

# 執行部署
kubectl apply -f nodetest-k8s.yaml

# 此指令會查 default namespace 的資源
kubectl get pods

# 指定刪除剛剛建立的 K8s
kubectl delete -f nodetest-k8s.yaml