使用 ingress-nginx 暴露服务

 

ingress-nginx： 

https://github.com/kubernetes/ingress-nginx/tree/nginx-0.20.0/deploy

 

kubernetes暴露服务的方式：ClusterIP、NodePort、LoadBalancer、ingress

我对于这几种模式，简单的理解如下，

ClusterIP，集群内的应用都可以访问，集群外部无法访问。

 

NodePort，相信初学者接触的第一个对外暴露服务的方式就是NodePort方式，是kubernetes引导外部流量到pod最原始的方式，

                    Nodeport即在每个node上开放一个特定端口，对应到某个pod的端口，集群外部通过 nodeIP:NodePort的方式进行访问，

它的缺点也比较明显：

每个端口对应一种服务，

每个node上都需要开放NodePort端口，

默认端口范围30000-32767，可以修改，

如果某个node的ip地址发生变化，可能需要人工干预

 

LoadBalancer，是暴露服务到internet的标准方式，每个服务对应一个单独的IP地址，转发所有流量到对应的服务，可以转发任意类型的流量，

这种方式，最大的缺点就是每个暴露的服务都需要有自己的IP地址

 

Ingress

ingress事实上不是一种服务类型。它处于多个服务的前端，扮演着“智能路由”或者集群入口的角色。

ingress可能是暴露服务最强大，也是最复杂的方式，它的控制器有各种类型，包括 Google Cloud Load Balancer， Nginx，Contour，Istio，等等。它还有各种插件，比如 cert-manager（https://github.com/jetstack/cert-manager），它可以为你的服务自动提供 SSL 证书。

如果想用一个ip暴露多个服务，这些服务都使用相同的7层协议，比如http，那ingres将是最有用的。

 

接下来，我们对ingress-nginx进行测试，

 

 一、部署

下载官方yaml文件

wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.20.0/deploy/mandatory.yaml

更新yaml里面两处镜像地址，此处使用的是阿里的镜像仓库

          image: registry.cn-hangzhou.aliyuncs.com/google_containers/defaultbackend:1.4
          image: registry.cn-hangzhou.aliyuncs.com/google_containers/nginx-ingress-controller:0.23.0

部署nginx-ingress-controller

[k8s@k8s-m1 ingress]$ kubectl apply -f mandatory.yaml
namespace/ingress-nginx created
deployment.extensions/default-http-backend created
service/default-http-backend 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.extensions/nginx-ingress-controller created

查看部署后的状态

#deployment状态
[k8s@k8s-m1 ingress]$ kubectl get deployment -n ingress-nginx
NAME                       DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
default-http-backend       1         1         1            1           7m
nginx-ingress-controller   1         1         1            1           7m
#pod状态
[k8s@k8s-m1 ingress]$ kubectl get pods  -n ingress-nginx -o wide
NAME                                        READY     STATUS    RESTARTS   AGE       IP            NODE                 NOMINATED NODE
default-http-backend-598df75c7d-ngfvs       1/1       Running   0          3m        172.60.75.2   k8s-m1               <none>
nginx-ingress-controller-67954599b4-hbkfg   1/1       Running   0          3m        172.60.19.3   vm10-10-8-10ksccom   <none>
#svc状态
[k8s@k8s-m1 ingress]$ kubectl get svc  -n ingress-nginx -o wide
NAME                   TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE       SELECTOR
default-http-backend   ClusterIP   10.240.44.251   <none>        80/TCP    4m        app.kubernetes.io/name=default-http-backend,app.kubernetes.io/part-of=ingress-nginx

default-http-backend是安装的一个默认后端，ClusterIP类型，可以在集群任意node访问，用于返回404结果

二、测试

[root@k8s-m2 ~]# curl http://10.240.44.251
default backend - 404
[root@k8s-m2 ~]# curl http://10.240.44.251/healthz
ok[root@k8s-m2 ~]#

 到这里，说明ingress-nginx已经部署成功了。

以上是通过default-http-backend进行访问，并没有对集群外部暴露服务，

接下来继续，看看对外暴露服务的方式

三、通过nodeport的方式将服务暴露出去

下载nodePort模板

wget  https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/baremetal/service-nodeport.yaml

default backend - 404[k8s@k8s-m1 ingress]$ cat service-nodeport.yaml
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
      port: 80
      targetPort: 80
      protocol: TCP
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---

#生效
[k8s@k8s-m1 ingress]$ kubectl create -f service-nodeport.yaml

查看svc状态

[k8s@k8s-m1 ingress]$ kubectl get svc -n ingress-nginx
NAME                   TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                    AGE
default-http-backend   ClusterIP   10.240.13.114   <none>        80/TCP                     44m
ingress-nginx          NodePort    10.240.82.29    <none>        80:8807/TCP,443:8956/TCP   40m
nginx-1108             ClusterIP   10.240.31.31    <none>        80/TCP,1935/TCP            42m

创建一个应用

[k8s@k8s-m1 ingress]$ cat nginx-1.10.2.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx-1108
  labels:
    app: nginx-1108
  namespace: ingress-nginx
spec:
  selector:
    app: nginx-1108
  ports:
  - name: http80
    port: 80
    targetPort: 80
  - name: rtmp1935
    port: 1935
    targetPort: 1935
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-1108
  labels:
    addonmanager.kubernetes.io/mode: Reconcile
  namespace: ingress-nginx
spec:
  template:
    metadata:
      labels:
        app: nginx-1108
    spec:
      containers:
      - name: my-nginx-1108
        image: rtmp-nginx:1.10.8
        imagePullPolicy: Never
        command: ["/usr/local/nginx/sbin/nginx","-g","daemon off;"]
        ports:
        - containerPort: 80

创建ingress规则

# 域名方式访问，本次使用域名方式测试
nginx-ingress]# cat ingress-host-nginx-1.10.2.yaml 
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: pand-ingress
  annotations:
    ingress.kubernetes.io/ssl-redirect: "false"
spec:
  rules:
  - host: www.test1.com
    http:
      paths:
      - backend:
          serviceName: nginx-1108
          servicePort: 80
          
# url路径方式访问
nginx-ingress]# cat ingress-path-nginx-1.10.2.yaml 
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: test-ingress
  annotations:
    ingress.kubernetes.io/ssl-redirect: "false" 
spec:
  rules:
  - http:
      paths:
      - path: /test1
        backend:
          serviceName: nginx-1108
          servicePort: 80

使用ingress域名规则进行测试

[root@k8s-m2 ~]# curl   http://10.240.82.29/
default backend - 404[
[root@k8s-m2 ~]# curl -H "Host: foo.bar.com"  http://10.240.82.29/
successfully
[root@k8s-m2 ~]# curl -H "Host: foo.bar.com"  http://nodePort+port/
successfully

 四、通过hostNetwork的方式，对外暴露服务

 修改mandatory.yaml，对nginx-ingress-controller添加hostNetwork: true，

hostNetwork是直接定义pod的网络方式，定义后，物理机ip就是nginx-ingress的ip，通过物理机ip直接访问nginx-ingress端口，将请求转发给后端pod

apiVersion: extensions/v1beta1
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
      serviceAccountName: nginx-ingress-serviceaccount
      nodeSelector:
        zone: test_node
      containers:
        - name: nginx-ingress-controller
          image: registry.cn-hangzhou.aliyuncs.com/google_containers/nginx-ingress-controller:0.23.0

 

kubectl apply -f mandatory.yaml 

查看pod所在物理机监听的端口，多了一个80端口，即nginx-ingress端口

tcp        0      0 10.10.8.11:2380         0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:8800            0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:8801            0.0.0.0:*               LISTEN

 

测试

#通过物理机ip测试
[k8s@k8s-m1 ~]$ curl http://10.69.58.68/
default backend - 404