ingress-nginx のデモ。

demo.md

ingress-nginx の様子をデモ。WebサービスA、サービスBを起動して、Ingressで振り分け。

1. LB (MetalLB) の準備

• NSX-T LB の代わり

MetalLB の IP レンジを決めておく。（ワーカーの IP レンジで。例： 10.0.3.221-10.0.3.229）

$ cat configmap.yml
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    address-pools:
    - name: default
      protocol: layer2
      addresses:
      - 10.0.3.221-10.0.3.229

metalLB インストール

$ kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.3/manifests/namespace.yaml
$ kubectl apply -f  https://raw.githubusercontent.com/metallb/metallb/v0.9.3/manifests/metallb.yaml
$ kubectl apply -f configmap.yml
$ kubectl create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"

2. nginx-ingress インストール

作成されるリソースを見ておく。

$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.43.0/deploy/static/provider/cloud/deploy.yaml --dry-run=client

作成

$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.43.0/deploy/static/provider/cloud/deploy.yaml

3. Pod の起動

サービスA

$ cat web-deploy-test-A.yml
---
kind: Service
apiVersion: v1
metadata:
  name: web-svc-a
  labels:
    app: web
    site: web-a
spec:
  type: LoadBalancer
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    site: web-a

---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: web-a
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demo-httpd
  template:
    metadata:
      labels:
        app: demo-httpd
        site: web-a
    spec:
      containers:
      - name: httpd
        image: gowatana/centos7:httpd
        ports:
        - containerPort: 80
          protocol: TCP
        command:
        - bash
        - -c
        - |
          N=$(uname -n); echo '<h1><font color="red">Site A</font> on TKG</h1>' $N > /var/www/html/index.html; httpd -D FOREGROUND

サービスB

$ cat web-deploy-test-B.yml
---
kind: Service
apiVersion: v1
metadata:
  name: web-svc-b
  labels:
    app: web
    site: web-b
spec:
  type: LoadBalancer
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    site: web-b

---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: web-b
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demo-httpd
  template:
    metadata:
      labels:
        app: demo-httpd
        site: web-b
    spec:
      containers:
      - name: httpd
        image: gowatana/centos7:httpd
        ports:
        - containerPort: 80
          protocol: TCP
        command:
        - bash
        - -c
        - |
          N=$(uname -n); echo '<h1><font color="blue">Site B</font> on TKG</h1>' $N > /var/www/html/index.html; httpd -D FOREGROUND

サービスAとBの起動

$ kubectl apply -f web-deploy-test-A.yml
$ kubectl apply -f web-deploy-test-B.yml

4. Ingress 作成

$ cat test-ingress-01.yml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: test-ingress-01
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - http:
      paths:
      - path: /site-a
        pathType: Prefix
        backend:
          service:
            name: web-svc-a
            port:
              number: 80
      - path: /site-b
        pathType: Prefix
        backend:
          service:
            name: web-svc-b
            port:
              number: 80

Ingress 作成

$ kubectl apply -f test-ingress-01.yml

5. 確認

Service LoadBalancer のIP

$ kubectl get svc
NAME         TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP      100.64.0.1       <none>        443/TCP        4d9h
web-svc-a    LoadBalancer   100.64.90.133    10.0.3.222    80:32740/TCP   14s
web-svc-b    LoadBalancer   100.65.209.202   10.0.3.223    80:30799/TCP   10s

Ingress の IP は 10.0.3.221

$ kubectl get ingress
Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress
NAME              CLASS    HOSTS   ADDRESS      PORTS   AGE
test-ingress-01   <none>   *       10.0.3.221   80      6m16s

アクセステスト

サービスA、サービスBの Service 直接

• http://10.0.3.222/
• http://10.0.3.223/

Ingress 経由

• http://10.0.3.221/site-a
• http://10.0.3.221/site-b

以上