Pod 的進階版講的差不多了，接著我們就要講一下 Service 的進階版 Ingress 。

前面的 Service 簡單說就只是單純地將端口打開，然後 Service 會為你指出某條路通向某個 Pod ，就只是這麼的簡單暴力。

而 Ingress 就不一樣了，還可以提供驗證、負載平衡、路由過濾等功能，方便我們的使用。

但是， Kubernetes 預設是沒有 IngressController 的（我印象中是這樣啦），因此我們需要先手動建立一個 IngressController ，等等才能幫我們調度 Ingress 。

首先因為這次資源有點多，所以我們先建立一個新的 Namespace 。

apiVersion: v1
kind: Namespace
metadata:
  name: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

接著再用 Nginx 建立兩個等等要用的網頁及各自的 Service 。

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod1
  namespace: default
  labels:
    app: nginx-pod1
spec:
  containers:
    - image: nginx:latest
      name: nginx
      ports:
        - containerPort: 80

---
apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod2
  namespace: default
  labels:
    app: nginx-pod2
spec:
  containers:
    - image: nginx:latest
      name: nginx
      ports:
        - containerPort: 80

---
apiVersion: v1
kind: Service
metadata:
  name: nginx-service-1
spec:
  selector:
    app: nginx-pod1
  ports:
    - protocol: TCP
      port: 8081
      targetPort: 80

---

apiVersion: v1
kind: Service
metadata:
  name: nginx-service-2
spec:
  selector:
    app: nginx-pod2
  ports:
    - protocol: TCP
      port: 8082
      targetPort: 80

接著我們先進入 Pod 內，修改一下顯示的內容，通常位置在 /usr/share/nginx/html/index.html ，我們主要是讓兩個 Pod 顯示出不一樣的內容可以辨識而已。

$ kubectl exec -it pod <pod name> -- bash

接著我們就可以來建立一個 Ingress Controller 了（如果用公有雲的話就不用這麼麻煩了）。

kind: ConfigMap
apiVersion: v1
metadata:
  name: nginx-configuration
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: tcp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: udp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nginx-ingress-serviceaccount
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: nginx-ingress-role
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - pods
      - secrets
      - namespaces
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - configmaps
    resourceNames:
      # Defaults to "<election-id>-<ingress-class>"
      # Here: "<ingress-controller-leader>-<nginx>"
      # This has to be adapted if you change either parameter
      # when launching the nginx-ingress-controller.
      - "ingress-controller-leader-nginx"
    verbs:
      - get
      - update
  - apiGroups:
      - ""
    resources:
      - configmaps
    verbs:
      - create
  - apiGroups:
      - ""
    resources:
      - endpoints
    verbs:
      - get

---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: nginx-ingress-role-nisa-binding
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: nginx-ingress-role
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: nginx-ingress-clusterrole
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - endpoints
      - nodes
      - pods
      - secrets
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - services
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - events
    verbs:
      - create
      - patch
  - apiGroups:
      - "extensions"
      - "networking.k8s.io"
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - "extensions"
      - "networking.k8s.io"
    resources:
      - ingresses/status
    verbs:
      - update

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: nginx-ingress-clusterrole-nisa-binding
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: nginx-ingress-clusterrole
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-ingress-controller
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: ingress-nginx
      app.kubernetes.io/part-of: ingress-nginx
  template:
    metadata:
      labels:
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx
      annotations:
        prometheus.io/port: "10254"
        prometheus.io/scrape: "true"
    spec:
      hostNetwork: true
      # wait up to five minutes for the drain of connections
      terminationGracePeriodSeconds: 300
      serviceAccountName: nginx-ingress-serviceaccount
      nodeSelector:
        kubernetes.io/os: linux
        #custem/ingress-controller-ready: "true"
      containers:
        - name: nginx-ingress-controller
          image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.33.0
          args:
            - /nginx-ingress-controller
            - --configmap=$(POD_NAMESPACE)/nginx-configuration
            - --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
            - --udp-services-configmap=$(POD_NAMESPACE)/udp-services
            - --publish-service=$(POD_NAMESPACE)/ingress-nginx
            - --annotations-prefix=nginx.ingress.kubernetes.io
          securityContext:
            allowPrivilegeEscalation: true
            capabilities:
              drop:
                - ALL
              add:
                - NET_BIND_SERVICE
            # www-data -> 101
            runAsUser: 101
          env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          ports:
            - name: http
              containerPort: 80
              #hostPort: 80
              protocol: TCP
            - name: https
              containerPort: 443
              #hostPort: 443
              protocol: TCP
          livenessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 10
          readinessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 10
          lifecycle:
            preStop:
              exec:
                command:
                  - /wait-shutdown

---
apiVersion: v1
kind: LimitRange
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  limits:
    - min:
        memory: 90Mi
        cpu: 100m
      type: Container

---
apiVersion: v1
kind: Service
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: NodePort
  ports:
    - name: http # 服務為http
      port: 80 # service端口为80
      targetPort: 80 # 容器端口为80
      protocol: TCP
      nodePort: 30080
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
      nodePort: 30443
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

最後終於要進入到我們的 Ingress 了。

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-nginx
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
    - host: my.example.com # 要轉的域名 -> http://"my.example.com"/pod1
      http:
        paths:
          - path: /pod1 # 自訂的path
            pathType: Prefix
            backend:
              service:
                name: nginx-service-1
                port:
                  number: 8081
          - path: /pod2
            pathType: Prefix
            backend:
              service:
                name: nginx-service-2
                port:
                  number: 8082

這樣就可以通過輸入不同的路由進入到不同的後端 Pod 了。

那麼就先到這邊，明天就要來講 Volume 的進階版了。

大家掰~掰~