Ingress 英文翻译 进入;进入权;进食，更准确的讲就是入口，即外部流量进入k8s集群必经之口。这道大门到底有什么作用？我们如何使用Ingress？k8s又是如何进行服务发现的呢？先看一张图：

OK。ingress 的作用可以做到 service nodeport 不能做到的 使用不同的web url 来指向不同的pod service 的功能。

下面开始部署：看了网上下载以下两个yaml: (和网上的路径有些不一样，原因是官方把原文件放了不同的位置)

https://github.com/kubernetes/ingress-nginx/blob/master/deploy/static/mandatory.yaml

https://github.com/kubernetes/ingress-nginx/blob/master/deploy/baremetal/service-nodeport.yaml

下载下来，kubectl apply -f  mandatory.yaml  和 service-nodeport.yaml 发现是jason 文件，我就去链接下面copy yaml 原代码，然后copy 到server 上， apply 一下就成功啦。

 

[root@k8s-master script]# kubectl apply -f mandatory.yaml
namespace/ingress-nginx created
configmap/nginx-configuration created
configmap/tcp-services created
configmap/udp-services created
serviceaccount/nginx-ingress-serviceaccount created
clusterrole.rbac.authorization.k8s.io/nginx-ingress-clusterrole created
role.rbac.authorization.k8s.io/nginx-ingress-role created
rolebinding.rbac.authorization.k8s.io/nginx-ingress-role-nisa-binding created
clusterrolebinding.rbac.authorization.k8s.io/nginx-ingress-clusterrole-nisa-binding created
deployment.apps/nginx-ingress-controller created

[root@k8s-master script]# kubectl get pod -n ingress-nginx -o wide
NAME                                        READY   STATUS    RESTARTS   AGE     IP            NODE       NOMINATED NODE   READINESS GATES
nginx-ingress-controller-568867bf56-6tvzv   1/1     Running   0          2m30s   10.244.1.17   k8s-node   <none>           <none>

### 通过创建的svc可以看到已经把ingress-nginx service在主机映射的端口为30239(http)，30949(https)

[root@k8s-master script]# kubectl get svc
NAME            TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx   NodePort    10.1.13.222    <none>        80:30239/TCP,443:30949/TCP   34s

2、验证

 2.1 创建svc及后端deployment

[root@k8s-master01 ingress-master]# cat test-ingress-pods.yml 
apiVersion: v1
kind: Service
metadata:
  name: myapp-svc
  namespace: default
spec:
  selector:
    app: myapp
    env: test
  ports:
  - name: http
    port: 80
    targetPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata: 
  name: myapp-test
spec:
  replicas: 2
  selector: 
    matchLabels:
      app: myapp
      env: test
  template:
    metadata:
      labels:
        app: myapp
        env: test
    spec:
      containers:
      - name: myapp
        image: nginx:1.15-alpine 
        ports:
        - name: httpd
          containerPort: 80
## 查看pod资源部署

[root@k8s-master script]# kubectl get pods
NAME                         READY   STATUS    RESTARTS   AGE
myapp-test-d84885678-7hzhj   1/1     Running   0          4m7s
myapp-test-d84885678-v959h   1/1     Running   0          4m7s

## 查看svc

[root@k8s-master script]# kubectl get svc
NAME            TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx   NodePort    10.1.13.222    <none>        80:30239/TCP,443:30949/TCP   43m
kubernetes      ClusterIP   10.1.0.1       <none>        443/TCP                      6d2h
myapp-svc       ClusterIP   10.1.235.146   <none>        80/TCP                       4m23s

2.2 创建ingress规则

## ingress规则中，要指定需要绑定暴露的svc名称
[root@k8s-master01 ingress-master]# cat test-ingress-myapp.yml 
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-myapp
  namespace: default
  annotations: 
    kubernetes.io/ingress.class: "nginx"
spec:
  rules:
  - host: www.shp.com
    http:
      paths:
      - path: 
        backend:
          serviceName: myapp-svc
          servicePort: 80

[root@k8s-master script]# kubectl apply -f test-ingress-myapp.yml
ingress.extensions/ingress-myapp created

[root@k8s-master script]# kubectl get ingress
NAME            HOSTS         ADDRESS   PORTS   AGE
ingress-myapp   www.shp.com             80      42s

2.3 在主机配置hosts域名解析

## 这里随机解析任一台节点主机都可以

1	192.168.122.152 www.shp

然后主机浏览器访问http://www.shp.com:30239，这里访问时需要加上svc映射到主机时随机产生的nodePort端口号。

[root@k8s-master script]# kubectl describe ingress ingress-myapp
Name:             ingress-myapp
Namespace:        default
Address:          
Default backend:  default-http-backend:80 (<none>)
Rules:
  Host         Path  Backends
  ----         ----  --------
  www.shp.com  
                  myapp-svc:80 (10.244.1.27:80,10.244.1.28:80)
Annotations:
  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"extensions/v1beta1","kind":"Ingress","metadata":{"annotations":{"kubernetes.io/ingress.class":"nginx"},"name":"ingress-myapp","namespace":"default"},"spec":{"rules":[{"host":"www.shp.com","http":{"paths":[{"backend":{"serviceName":"myapp-svc","servicePort":80},"path":null}]}}]}}

  kubernetes.io/ingress.class:  nginx
Events:
  Type    Reason  Age   From                      Message
  ----    ------  ----  ----                      -------
  Normal  CREATE  38m   nginx-ingress-controller  Ingress default/ingress-myapp

------

下面进入容器看看nginx 是否已经进来了：

[root@k8s-master script]# kubectl exec -n ingress-nginx -it nginx-ingress-controller-568867bf56-6tvzv bash
www-data@nginx-ingress-controller-568867bf56-6tvzv:/etc/nginx$ cat nginx.conf

    ## start server www.shp.com
    server {
        server_name www.shp.com ;
        
        listen 80  ;
        listen 443  ssl http2 ;
        
        set $proxy_upstream_name "-";
        
        ssl_certificate_by_lua_block {
            certificate.call()
        }
        
        location / {
            
            set $namespace      "default";
            set $ingress_name   "ingress-myapp";
            set $service_name   "myapp-svc";
            set $service_port   "80";
            set $location_path  "/";

我测试了一把，发现： curl www.shp.com 被拒绝，

所以不能打开，下面研究改一下。

看了是因为80 端口没有暴露，修改在mandatory.yaml 的:(红色部分)

[root@k8s-master script]# cat mandatory.yaml
apiVersion: v1
kind: Namespace
metadata:
  name: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---

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/v1beta1
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/v1beta1
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/v1beta1
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/v1beta1
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:
      # wait up to five minutes for the drain of connections
      terminationGracePeriodSeconds: 300
      serviceAccountName: nginx-ingress-serviceaccount
      hostNetwork: true
      nodeSelector:
        kubernetes.io/os: linux
      containers:
        - name: nginx-ingress-controller
          image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.26.1
          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 -> 33
            runAsUser: 33
          env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          ports:
            - name: http
              containerPort: 80
            - name: https
              containerPort: 443
          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

---

然后再 apply 一下：

root@k8s-master script]# kubectl apply -f mandatory.yaml
namespace/ingress-nginx unchanged
configmap/nginx-configuration unchanged
configmap/tcp-services unchanged
configmap/udp-services unchanged
serviceaccount/nginx-ingress-serviceaccount unchanged
clusterrole.rbac.authorization.k8s.io/nginx-ingress-clusterrole unchanged
role.rbac.authorization.k8s.io/nginx-ingress-role unchanged
rolebinding.rbac.authorization.k8s.io/nginx-ingress-role-nisa-binding unchanged
clusterrolebinding.rbac.authorization.k8s.io/nginx-ingress-clusterrole-nisa-binding unchanged
deployment.apps/nginx-ingress-controller configured

[root@k8s-master script]# kubectl apply -f test-ingress-pods.yaml
service/myapp-svc unchanged
deployment.apps/myapp-test unchanged
[root@k8s-master script]# kubectl apply -f test-ingress-myapp.yml
ingress.extensions/ingress-myapp configured

现在再看一下ingress-control 的变化：

[root@k8s-master script]# kubectl get pod -n ingress-nginx
NAME                                        READY   STATUS        RESTARTS   AGE
nginx-ingress-controller-568867bf56-6tvzv   1/1     Terminating   2          20h
nginx-ingress-controller-5bbd46cd86-mwrjz   1/1     Running       0          15s

原来的pod 在 terminate, 好事，下面看看：

[root@k8s-master script]# kubectl get pod -n ingress-nginx -o wide
NAME                                        READY   STATUS    RESTARTS   AGE     IP               NODE       NOMINATED NODE   READINESS GATES
nginx-ingress-controller-5bbd46cd86-mwrjz   1/1     Running   0          2m22s   192.168.122.61   k8s-node   <none>           <none>

发现现在的ingress 的IP 变成 node 的IP，然后再测试一下：

[root@k8s-master script]# kubectl get svc
NAME            TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx   NodePort    10.1.13.222    <none>        80:30239/TCP,443:30949/TCP   20h

[root@k8s-master script]# curl 192.168.122.61 30239
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>openresty/1.15.8.2</center>
</body>
</html>

测试成功！