k8sで自分のホスト名を返すnginxのPodとService

Pod

nginx-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    label: nginx-label
spec:
  containers:
  - name: nginx-container
    image: nginx
    ports:
    - containerPort: 80
    command: [ "sh", "-c", "
      ln -sf /etc/hostname /usr/share/nginx/html/index.html;
      nginx -g 'daemon off;';
    "]

$ kubectl apply -f nginx-pod.yaml
pod/nginx-pod created

$ # yaml を使わない場合
$ kubectl run nginx-pod --image=nginx --generator=run-pod/v1 --port=80 --labels=label=nginx-label -- sh -c "ln -sf /etc/hostname /usr/share/nginx/html/index.html; nginx -g 'daemon off;';"
pod/nginx-pod created

$ # 確認 (クラスタ内から nginx-pod を叩く)
$ kubectl run curl --image=curlimages/curl -it --rm --restart=Never -- curl $(kubectl get pod nginx-pod -o jsonpath='{.status.podIP}')
nginx-pod
pod "curl" deleted

Service (NodePort)

nginx-svc.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-svc
spec:
  type: NodePort
  ports:
  - port: 8080
    targetPort: 80
    nodePort: 30080 # コメントアウトで空きポートを自動選択
  selector:
    label: nginx-label

$ kubectl apply -f nginx-svc.yaml
service/nginx-svc created

$ # yaml を使わない場合 (nodePort は自動選択)
$ kubectl expose pod nginx-pod --type=NodePort --name=nginx-svc --port=8080 --target-port=80
service/nginx-svc exposed

$ # nodePortを指定
$ kubectl patch svc nginx-svc --type=json -p='[{"op": "replace", "path": "/spec/ports/0/nodePort", "value": 30080}]'
service/nginx-svc patched

$ # 確認 (クラスタ外から叩く)
$ # curl workernode:30080
$ curl $(kubectl get node -o jsonpath='{.items[0].status.addresses[?(@.type=="InternalIP")].address}'):$(kubectl get svc nginx-svc -o jsonpath='{.spec.ports[0].nodePort}')
nginx-pod