Docker & Kubernetes — الدليل الشامل من الحاويات المنفردة إلى إدارة العناقيد السحابية

+-----------------------+              +-----------------------+
|  Developer Machine    |              |   Production Server   |
|  - Node.js v20.x      |   Deploy     |  - Node.js v16.x (💥) |
|  - PostgreSQL 16      | -----------> |  - PostgreSQL 13 (💥) |
|  - Dependencies OK    |              |  - Missing Libs (💥)  |
|  ==> RUNNING PASS ✅   |              |  ==> CRASHED 500 ❌   |
+-----------------------+              +-----------------------+

# 1. Base Image
FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS base
WORKDIR /app
EXPOSE 8080

# 2. Build Stage
FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src
COPY ["MyApp.csproj", "./"]
RUN dotnet restore "./MyApp.csproj"
COPY . .
RUN dotnet build "MyApp.csproj" -c Release -o /app/build

# 3. Publish Stage
FROM build AS publish
RUN dotnet publish "MyApp.csproj" -c Release -o /app/publish /p:UseAppHost=false

# 4. Final Runtime
FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "MyApp.dll"]

Dockerfile (الوصف) ──[docker build]──> Docker Image (الحزمة المدمجة) ──[docker run]──> Container (الحاوية قيد التشغيل)

+-----------------------------------+    +-----------------------------------+
|       Virtual Machines (VMs)      |    |        Docker Containers          |
+-----------------------------------+    +-----------------------------------+
|  [App A]   [App B]   [App C]      |    |  [App A]   [App B]   [App C]      |
|  [Bins/Lib][Bins/Lib][Bins/Lib]   |    |  [Bins/Lib][Bins/Lib][Bins/Lib]   |
|  [Guest OS][Guest OS][Guest OS]   |    |         [Docker Engine]           |
|  +-----------------------------+  |    |  +-----------------------------+  |
|  |    Hypervisor (Type 1 / 2)  |  |    |  |     Host OS & Linux Kernel  |  |
|  +-----------------------------+  |    |  +-----------------------------+  |
|  |      Physical Hardware      |  |    |  |      Physical Hardware      |  |
|  +-----------------------------+  |    |  +-----------------------------+  |
+-----------------------------------+    +-----------------------------------+

version: '3.8'

services:
  api:
    build: .
    ports:
      - "8080:8080"
    environment:
      - DB_HOST=postgres
      - REDIS_HOST=redis
    depends_on:
      - postgres
      - redis

  postgres:
    image: postgres:16-alpine
    environment:
      POSTGRES_DB: myapp
      POSTGRES_USER: user
      POSTGRES_PASSWORD: secretpassword
    volumes:
      - pgdata:/var/lib/postgresql/data

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

volumes:
  pgdata:

+-------------------------------------------------------------------------------+
|                            KUBERNETES CLUSTER                                 |
+-------------------------------------------------------------------------------+
|  [ Control Plane (Master Node) ]                                              |
|  - API Server | etcd (State Store) | Scheduler | Controller Manager           |
+-------------------------------------------------------------------------------+
|  [ Worker Node 1 ]                |  [ Worker Node 2 ]                        |
|  - Kubelet | Kube-Proxy | Runtime |  - Kubelet | Kube-Proxy | Runtime         |
|  +-----------------------------+  |  +-----------------------------+          |
|  | Pod (App v1) | Pod (App v1) |  |  | Pod (App v1) | Pod (Redis)  |          |
|  +-----------------------------+  |  +-----------------------------+          |
+-------------------------------------------------------------------------------+

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myregistry/myapp:v1.2.0
        ports:
        - containerPort: 8080
        resources:
          limits:
            memory: "512Mi"
            cpu: "500m"
          requests:
            memory: "256Mi"
            cpu: "250m"

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  type: ClusterIP
  selector:
    app: myapp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8080