কুবারনেটিস (K8s)

kubectl run nginx-pod --image=nginx --restart=Never
kubectl get pods

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    app: nginx
spec:
  containers:
  - name: nginx
    image: nginx:latest
    ports:
    - containerPort: 80

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
  labels:
    app: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80

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

kubectl get pods -n kube-system

apiVersion: v1
kind: PersistentVolume
metadata:
  name: my-pv
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data"

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: nginx
    image: nginx
    volumeMounts:
    - mountPath: "/usr/share/nginx/html"
      name: my-storage
  volumes:
  - name: my-storage
    persistentVolumeClaim:
      claimName: my-pvc

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
spec:
  rules:
  - host: "example.com"
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 80

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data:
  database_url: "mysql://localhost:3306"
  log_level: "debug"

spec:
  containers:
  - name: myapp
    image: myapp
    env:
    - name: DB_URL
      valueFrom:
        configMapKeyRef:
          name: my-config
          key: database_url

apiVersion: v1
kind: Secret
metadata:
  name: my-secret
type: Opaque
data:
  password: cGFzc3dvcmQ= # base64 এনকোডেড "password"

spec:
  containers:
  - name: myapp
    image: myapp
    env:
    - name: PASSWORD
      valueFrom:
        secretKeyRef:
          name: my-secret
          key: password

apiVersion: v1
kind: Pod
metadata:
  name: resource-pod
spec:
  containers:
  - name: nginx
    image: nginx
    resources:
      requests:
        memory: "64Mi"
        cpu: "250m" # 0.25 CPU
      limits:
        memory: "128Mi"
        cpu: "500m" # 0.5 CPU

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: myapp-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: myapp-deployment
  minReplicas: 1
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 50

kubectl logs mypod -f # রিয়েল-টাইম লগ
kubectl logs -l app=myapp # লেবেল দিয়ে

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: my-ns
  name: pod-reader
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get", "list"]

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: read-pods
  namespace: my-ns
subjects:
- kind: User
  name: "user1"
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: pod-reader
  apiGroup: rbac.authorization.k8s.io

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-app
  namespace: my-ns
spec:
  podSelector:
    matchLabels:
      app: myapp
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: frontend
    ports:
    - protocol: TCP
      port: 80

kubectl get nodes
kubeadm upgrade plan
sudo kubeadm upgrade apply v1.XX.X

name: Deploy to K8s
on:
  push:
    branches: [main]
jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v3
    - name: Set up kubectl
      uses: azure/setup-kubectl@v3
      with:
        version: 'latest'
    - name: Deploy
      run: |
        kubectl apply -f deployment.yaml
      env:
        KUBE_CONFIG: ${{ secrets.KUBE_CONFIG }}

apiVersion: apps/v1
kind: Deployment
metadata:
  name: webapp
spec:
  replicas: 2
  selector:
    matchLabels:
      app: webapp
  template:
    metadata:
      labels:
        app: webapp
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80
        resources:
          requests:
            cpu: "100m"
            memory: "128Mi"
          limits:
            cpu: "200m"
            memory: "256Mi"

apiVersion: v1
kind: Service
metadata:
  name: webapp-service
spec:
  selector:
    app: webapp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  type: LoadBalancer

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: webapp-ingress
spec:
  rules:
  - host: "myapp.local"
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: webapp-service
            port:
              number: 80

kubectl apply -f app-deployment.yaml
kubectl apply -f app-service.yaml
kubectl apply -f app-ingress.yaml
kubectl get all