Ch07

Chapter 7: Exposing Applications

Documentation

• kubernetes.io > Concepts > Services, Load Balancing, and Networking > Service

Generate Service

kubectl create service clusterip    app2 --tcp=80 --dry-run -o yaml
kubectl create service nodeport     app2 --tcp=80 --node-port=32000 --dry-run -o yaml
kubectl create service loadbalancer app2 --tcp=80 --dry-run -o yaml

Or

kubectl expose pod nginx        --port=80 [--type=ClusterIP]  --dry-run -o yaml
kubectl expose deployment nginx --port=80 --type=NodePort     --dry-run -o yaml
kubectl expose rc nginx         --port=80 --type=LoadBalancer --dry-run -o yaml

Using kubectl create service does not create the EndPoints for a NodePort service, instead use kubectl expose and add the nodePort: PORT to Service.spec.ports[N].nodePort.

Validate a Service

kubectl get services

clusterIP=$(kubectl get service app2 -o jsonpath='{$.spec.clusterIP}')
kubectl run busybox --image=busybox -it --rm --restart=Never -- sh -c "wget -q -O- http://${clusterIP}:${ServiceIP} | head -10"

curl -s http://${NodeIP}:${ServiceIP} | head -10
  
lbPort=$(kubectl get service app2 -o jsonpath='{$.spec.ports[0].nodePort}')
curl -s http://localhost${lbPort | port} | head -10

Notes from the Training

From: kubernetes.io > Concepts > Services, Load Balancing, and Networking > Service

Create a Service with kubectl

kubectl expose deployment/nginx --port=80 --type=NodePort
kubectl get services
kubectl get service nginx -o yaml

Get the port from Service.spec.ports.nodePort to open http://<publicIP>:<nodePort>/

Ingress Controllers

List of Ingress Controllers:

• Nginx
• GCE
• Traefik
• HAProxy

Service Mesh

• Envoy
• Istio
• linkerd