Kubernetes Services and Ingress

apiVersion: v1
kind: Service
metadata:
  name: api
spec:
  selector:
    app: api
  ports:
    - port: 80
      targetPort: 3000

# Access from another pod
curl http://api.default.svc.cluster.local
# Or just
curl http://api

apiVersion: v1
kind: Service
metadata:
  name: api
spec:
  type: NodePort
  selector:
    app: api
  ports:
    - port: 80
      targetPort: 3000
      nodePort: 30080

apiVersion: v1
kind: Service
metadata:
  name: api
spec:
  type: LoadBalancer
  selector:
    app: api
  ports:
    - port: 80
      targetPort: 3000

kubectl get svc api
# EXTERNAL-IP shows the load balancer address

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

# Nginx Ingress Controller
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.10.0/deploy/static/provider/cloud/deploy.yaml

# Verify
kubectl get pods -n ingress-nginx

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: app-ingress
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt-prod
spec:
  ingressClassName: nginx
  tls:
    - hosts:
        - api.example.com
      secretName: api-tls
  rules:
    - host: api.example.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: api
                port:
                  number: 80

spec:
  rules:
    - host: example.com
      http:
        paths:
          - path: /api
            pathType: Prefix
            backend:
              service:
                name: api
                port:
                  number: 80
          - path: /
            pathType: Prefix
            backend:
              service:
                name: frontend
                port:
                  number: 80

# Check endpoints (pods backing the service)
kubectl get endpoints api

# No endpoints? Labels don't match
kubectl get pods --show-labels
kubectl describe svc api

# Test from inside cluster
kubectl run curl --image=curlimages/curl --rm -it -- curl http://api

# Check Ingress
kubectl describe ingress app-ingress
kubectl get ingress