1. metadata

2. spec

• desired status

3. status

• actual status
• automatically generated and added by kubernetes
• Etcd holds the current status of kubernetes components

Pods from the same deployment have the same labels

Selector uses the labels to know which pods belong to the deployment

Pod label, selector label in deployment, deployment label, and service label should be same

Service uses the labels to create connection

Names are used as the reference, can be arbitrary names

apiVersion: apps/v1
kind: Deployment # type
metadata:
  name: nginx-deployment # deployment name
  labels:
    app: nginx
spec: # specification for deployment
  replicas: 1 # number of replicas
  selector:
    matchLabels:
      app: nginx
  template: # specification for pods
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.16
        ports:
        - containerPort: 8080 # container access port
        

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80 # service port
      targetPort: 8080 # container port
        

apiVersion: v1
kind: Secret
metadata:
  name: mongo-secret
type: Opaque
data:
  mongo-user: bW9uZ291c2Vy
  mongo-password: bW9uZ29wYXNzd29yZA==
        

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: minimal-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx-example
  rules:
  - http:
      paths:
      - path: /testpath
        pathType: Prefix
        backend:
          service:
            name: test
            port:
              number: 80
        

Command-line tools for Kubernetes: kubectl, stern, kubectx, kubens

Kubernetes best practices: Organizing with Namespaces