Kubernetes Complete Course

Definition: Smallest deployable unit in Kubernetes.

• Contains one or more containers
• Shared network & storage
• Usage: Runs your application

apiVersion: v1              # API version for Pod
kind: Pod                  # Resource type
metadata:
  name: my-pod             # Name of the Pod
spec:
  containers:
    - name: my-container   # Container name inside Pod
      image: nishan023/my-app:01         # Docker image to run
      ports:
        - containerPort: 80 # Exposes port 80 inside container

Definition: A way to expose Pods so they can be accessed.

Why needed: Pods change IP when restarted, Service provides stable IP/DNS.

• ClusterIP: internal
• NodePort: external via port
• LoadBalancer: cloud access

apiVersion: v1
kind: Service              # Exposes Pods
metadata:
  name: my-service         # Service name
spec:
  selector:
    app: my-app            # Selects Pods with this label
  ports:
    - protocol: TCP        # Network protocol
      port: 80             # Service port (external)
      targetPort: 80       # Pod container port
  type: NodePort           # Makes service accessible from outside cluster

Definition: Manages external HTTP/HTTPS access to services based on URL routing.

Usage: Routing based on URL/path. Why use: No need multiple ports, works like smart router.

apiVersion: networking.k8s.io/v1
kind: Ingress              # Manages external HTTP/HTTPS access
metadata:
  name: my-ingress
spec:
  rules:
    - host: example.com    # Domain name
      http:
        paths:
          - path: /        # URL path
            pathType: Prefix
            backend:
              service:
                name: my-service  # Target service
                port:
                  number: 80      # Service port

Definition: Stores non-sensitive configuration data

Usage: Pass config to Pods without changing code

apiVersion: v1
kind: ConfigMap            # Stores non-sensitive config
metadata:
  name: my-config
data:
  APP_MODE: production     # App environment setting
  DB_HOST: localhost       # Database host

Definition: Stores sensitive data securely (Passwords, API keys, Tokens)

Usage: Inject into Pods safely. More secure than ConfigMap.

apiVersion: v1
kind: Secret               # Stores sensitive data
type: Opaque               # Generic secret type
metadata:
  name: my-secret
data:
  username: YWRtaW4=       # base64 encoded 'admin'
  password: cGFzc3dvcmQ=   # base64 encoded 'password'

Definition: Manages Pods automatically (healing, rolling updates, scaling).

What it does: Creates Pods, Scales Pods, Updates Pods. If you want 3 pods → Deployment ensures always 3 running.

apiVersion: apps/v1
kind: Deployment           # Manages Pods automatically
metadata:
  name: my-deployment
spec:
  replicas: 3              # Number of Pod copies
  selector:
    matchLabels:
      app: my-app          # Matches Pods with this label
  template:
    metadata:
      labels:
        app: my-app        # Label applied to Pods
    spec:
      containers:
        - name: my-container
          image: nishan023/my-app:01     # Container image
          ports:
            - containerPort: 80

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

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

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
        - name: my-container
          image: nishan023/my-app:01
          volumeMounts:
            - mountPath: /app/data
              name: my-storage
      volumes:
        - name: my-storage
          persistentVolumeClaim:
            claimName: my-pvc

minikube start --driver=docker

kubectl apply -f mongo-config.yaml
kubectl apply -f mongo-secret.yaml
kubectl apply -f mongo.yaml
kubectl apply -f web.yaml

kubectl get pods

kubectl expose deployment webapp --type=LoadBalancer --port=3000

minikube service webapp-service