26.kubernetes(k8s)笔记 Ingress(一)

前言:

什么是Ingress？

官方的解释是:
Ingress 是对集群中服务的外部访问进行管理的 API 对象，典型的访问方式是 HTTP。
Ingress 可以提供负载均衡、SSL 终结和基于名称的虚拟托管。

• Ingress简介
  Ingress对象，其实就是对“反向代理”的一种抽象，简单的说就是一个全局的负载均衡器，可以通过访问URL定位到后端的Service
  有了Ingress这个抽象，K8S就不需要关心Ingress的细节了，实际使用时，只需要选择一个具体的Ingress Controller部署就行了，业界常用的反向代理项目有：Nginx、HAProxy、Envoy、Traefik 都已经成为了K8S专门维护的Ingress Controller
  一个Ingress对象的主要内容，就类似Nginx的配置文件描述，对应的转发规则就是ingressRule，
  有了Ingress这个对象，用户就可以根据自己的需求选择Ingress Controller，例如，如果应用对代理服务的中断非常敏感，可以使用Treafik这样的Ingress Controller

Ingress工作在七层，Service工作在四层，当想要在Kubernetes里为应用进行TLS配置等HTTPS相关操作时，都必须通过Ingress来进行

• ingress-nginx 简单的理解就是你原来需要改 Nginx 配置，然后配置各种域名对应哪个 Service，现在把这个动作抽象出来，变成一个 Ingress 对象，你可以用 yaml 创建，每次不要去改 Nginx 了，直接改 yaml 然后创建/更新就行了；那么问题来了：”Nginx 该怎么处理？”

• Ingress Controller 这东西就是解决 “Nginx 的处理方式” 的；Ingress Controoler 通过与 Kubernetes API 交互，动态的去感知集群中 Ingress 规则变化，然后读取他，按照他自己模板生成一段 Nginx 配置，再写到 Nginx Pod 里，最后 reload 一下，工作流程如下图：

  
  

• 实际上Ingress也是Kubernetes API的标准资源类型之一，它其实就是一组基于DNS名称（host）或URL路径把请求转发到指定的Service资源的规则。用于将集群外部的请求流量转发到集群内部完成的服务发布。我们需要明白的是，Ingress资源自身不能进行“流量穿透”，仅仅是一组规则的集合，这些集合规则还需要其他功能的辅助，比如监听某套接字，然后根据这些规则的匹配进行路由转发，这些能够为Ingress资源监听套接字并将流量转发的组件就是Ingress Controller

• Ingress 两种路由方式
  1.虚拟主机
  2.URL 路径

Ingree-nginx部署

• ingress-nginx 很多全局配置或修改默认配置都是通过annotations 注释来加载配置文件具体参数详细解释可
  参考官方文档：

https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/

• 选择NodePort部署方式

https://kubernetes.github.io/ingress-nginx/deploy/

• extensions/v1beta1 Ingress资源规范 1.22+版本后会被彻底弃用

apiVersion: extensions/v1betal #资源所属的API群组和版本
Kind: Ingress#资源类型标识符
metadata: #元数据
  name <string> #资源名称
  annotationsl #资源注解,v1betal使用下面的注解来指定要解析该资源的控制器类型
    kubernetes.io/ingress.class: <string> #适配的Ingress控制器类别
  namespace <string> #名称空间
spec:
  rules <[]Object> #Ingress规则列表;
  - host <string>  #虚拟主机的FQDN，支持“*"前缀通配，不支持IP，不支持指定端口
    http <object>
      paths<[]0bject>#虚拟主机PATH定义的列表，由path和backend组成
      - path <string> #流量匹配的HTTP PATH，必须以/开头
        pathType <string> #匹配机制，支持Exact、_Prefix和ImplementationSpecific
        backend <object> #匹配到的流量转发到的目标后端
          resource <Object> #引用的同一名称空间下的资源，与下面两个字段互斥
          serviceName <string>#引用的Service资源的名称
          servicePort <string># Service用于提供服务的端口
  tls <[]object> #TLS配置，用于指定上rules中定义的哪些host需要工作HTTPS模式
  - hosts <[]string>  #使用同一组证书的主机名称列表
    secretName <string>  #保存于数字证书和私钥信息的secret资源名称
  backend <object>   #默认backend的定义，可嵌套字段及使用格式跟rules字段中的相同
  ingressClassName <string> #ingress类名称，用于指定适配的控制器

• v1 Ingress资源规范

apiVersion: networking.k8s.io/v1 #资源所属的API群组和版本
kind: Ingress #资源类型标识符
metadata: #元数据
  name <string> #资源名称
  annotations: #资源注解,vlbetal使用下面的注解来指定要解析该资源的控制器类型
    kubernetes.io/ingress.class:<string> #适配的Ingress控制器类别
  namespace <string>  #名称空间
spec:
  rules <[]object> #Ingress规则列表
  - host <string>  #虚拟主机的FQDN，支持“*"前缀通配，不支持IP，不支持指定端口
    http <object>
      paths <[]object>#虚拟主机PATH定义的列表，由path和backend组成
      - path <string> #流量匹配的HTTP PATH，必须以/开头
        pathType <string> #支持Exact、Prefix和ImplementationSpecific，必选
        backend <Object>#匹配到的流量转发到的目标后端
          resource <object>  #引用的同一名称空间下的资源，与下面两个字段互斥
          service <object> #关联的后端Service对象
            name <string> #后端Service的名称
            port bject> #后端Service上的端口对象
              name <string> #端口名称
              number <integer>  #端口号
  tls <[]object>  #TLS配置，用于指定上rules中定义的哪些host需要工作HTTPS模式
  - hosts <[]string>  #使用同一组证书的主机名称列表
    secretName <string> #保存于数字证书和私钥信息的secret资源名称
  backend <object>  #默认backend的定义，可嵌套字段及使用格式跟rules字段中的相同
  ingressClassName <string> #ingress类名称，用于指定适配的控制器

• 添加externalIPs:节点3 IP非必须步骤，方便记忆使用 而不是记忆NodePort端口 NodePort与externalIPs可同时访问

[root@k8s-master Ingress]# vim deploy.yaml
...
---
# Source: ingress-nginx/templates/controller-service.yaml
apiVersion: v1
kind: Service
metadata:
  annotations:
  labels:
    helm.sh/chart: ingress-nginx-4.0.1
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/version: 1.0.0
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/component: controller
  name: ingress-nginx-controller
  namespace: ingress-nginx
spec:
  type: NodePort
  externalIPs: [192.168.54.173]   #添加externalIPs字段 固定访问IP
  ports:
    - name: http
      port: 80
      protocol: TCP
      targetPort: http
      appProtocol: http
    - name: https
      port: 443
      protocol: TCP
      targetPort: https
      appProtocol: https
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/component: controller
...

• 部署Ingress-nginx

[root@k8s-master Ingress]# kubectl apply -f deploy.yaml 
namespace/ingress-nginx unchanged
serviceaccount/ingress-nginx unchanged
configmap/ingress-nginx-controller configured
clusterrole.rbac.authorization.k8s.io/ingress-nginx unchanged
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx unchanged
role.rbac.authorization.k8s.io/ingress-nginx unchanged
rolebinding.rbac.authorization.k8s.io/ingress-nginx unchanged
service/ingress-nginx-controller-admission unchanged
service/ingress-nginx-controller configured
deployment.apps/ingress-nginx-controller configured
ingressclass.networking.k8s.io/nginx unchanged
validatingwebhookconfiguration.admissionregistration.k8s.io/ingress-nginx-admission configured
serviceaccount/ingress-nginx-admission unchanged
clusterrole.rbac.authorization.k8s.io/ingress-nginx-admission unchanged
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx-admission unchanged
role.rbac.authorization.k8s.io/ingress-nginx-admission unchanged
rolebinding.rbac.authorization.k8s.io/ingress-nginx-admission unchanged
job.batch/ingress-nginx-admission-create unchanged
job.batch/ingress-nginx-admission-patch unchanged
[root@k8s-master Ingress]# kubectl get pod
NAME                              READY   STATUS    RESTARTS   AGE
etcd-operator-646cbffdb6-brbn6    1/1     Running   0          19h
example-etcd-cluster-5fb5d9d6n8   1/1     Running   0          49m
example-etcd-cluster-nc8pdgjrjr   1/1     Running   0          19h
example-etcd-cluster-svgdngq28k   1/1     Running   0          48m
[root@k8s-master Ingress]# kubectl get svc -n ingress-nginx
NAME                                 TYPE        CLUSTER-IP     EXTERNAL-IP      PORT(S)                      AGE
ingress-nginx-controller             NodePort    10.109.24.78   192.168.54.173   80:32493/TCP,443:30239/TCP   120m
ingress-nginx-controller-admission   ClusterIP   10.110.72.52   <none>           443/TCP                      120m

示例1：创建 Ingress-nginx虚拟主机

• 创建 Deployment 和与之对应的SVC

[root@k8s-master Ingress]# cat deployment-demo.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment-demo
  namespace: default
spec:
  replicas: 4
  selector:
    matchLabels:
      app: demoapp
      release: stable
  template:
    metadata:
      labels :
        app: demoapp
        release: stable
    spec:
      containers:
      - name: demoapp
        image: ikubernetes/demoapp:v1.1
        ports:
        - containerPort: 80
          name: http

---
apiVersion: v1
kind: Service
metadata:
  name: demoapp-deploy
  namespace: default
spec:
  selector:
    app: demoapp
    release: stable
  ports:
  - name: http
    port: 80
    targetPort: 80

• 创建 ingress-nginx

[root@k8s-master Ingress]# cat  demoapp-ingress.yaml 
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-demo
  annotations:
    kubernetes.io/ingress.class: "nginx"
  namespace: default
spec:
  rules:
  - host: www.ik8s.io  #虚拟主机
    http:
      paths:
      - path: /
        pathType: Prefix  #前缀匹配
        backend:
          service:
            name: demoapp-deploy
            port:
              number: 80

[root@k8s-master Ingress]# kubectl apply -f deployment-demo.yaml
[root@k8s-master Ingress]# kubectl apply -f demoapp-ingress.yaml

[root@k8s-master Ingress]# kubectl get svc -n ingress-nginx
NAME                                 TYPE        CLUSTER-IP     EXTERNAL-IP      PORT(S)                      AGE
ingress-nginx-controller             NodePort    10.109.24.78   192.168.54.173   80:32493/TCP,443:30239/TCP   5h50m
ingress-nginx-controller-admission   ClusterIP   10.110.72.52   <none>           443/TCP                      5h50m

[root@k8s-master Ingress]# 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
ingress-demo   <none>   www.ik8s.io   192.168.4.171   80      3h11m

• 访问测试

[root@bigyong ~]# cat /etc/hosts   
# ::1       localhost localhost.localdomain localhost6 localhost6.localdomain6
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4

...
192.168.54.173   www.ik8s.io   #写hosts

[root@bigyong ~]# curl 192.168.54.173  #直接访问只能到ingress-nginx 没到转发到后端
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx</center>
</body>
</html>
[root@bigyong ~]# curl -H  "Host:www.ik8s.io" 192.168.54.173  #访问成功
iKubernetes demoapp v1.1 !! ClientIP: 192.168.113.37, ServerName: deployment-demo-867c7d9d55-gw6qp, ServerIP: 192.168.113.39
[root@bigyong ~]# curl -H  "Host:www.ik8s.io" 192.168.54.173
iKubernetes demoapp v1.1 !! ClientIP: 192.168.113.37, ServerName: deployment-demo-867c7d9d55-9lnpq, ServerIP: 192.168.12.39!
[root@bigyong ~]# curl -H  "Host:www.ik8s.io" 192.168.54.173
iKubernetes demoapp v1.1 !! ClientIP: 192.168.113.37, ServerName: deployment-demo-867c7d9d55-2zcr5, ServerIP: 192.168.51.61!
[root@bigyong ~]# curl -H  "Host:www.ik8s.io" 192.168.54.173
iKubernetes demoapp v1.1 !! ClientIP: 192.168.113.37, ServerName: deployment-demo-867c7d9d55-9lnpq, ServerIP: 192.168.12.39!

示例2： 创建TLS Ingress HTTPS

[root@k8s-master Ingress]# cat   demoapp-ingress.yaml 
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-demo
  annotations:
    kubernetes.io/ingress.class: "nginx"
  namespace: default
spec:
  rules:
  - host: www.ik8s.io
    http:
      paths:
      - path: /
        pathType: Prefix  #前缀匹配
        backend:
          service:
            name: demoapp-deploy
            port:
              number: 80
  tls:  #添加tls
  - hosts:
    - www.ik8s.io
    secretName: ik8s-tls
    
[root@k8s-master Ingress]# kubectl  apply -f demoapp-ingress.yaml 
ingress.networking.k8s.io/ingress-demo configured

[root@k8s-master Ingress]# kubectl describe ingress ingress-demo
Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress
Name:             ingress-demo
Namespace:        default
Address:          192.168.4.171
Default backend:  default-http-backend:80 (<error: endpoints "default-http-backend" not found>)
TLS:
  ik8s-tls terminates www.ik8s.io
Rules:
  Host         Path  Backends
  ----         ----  --------
  www.ik8s.io  
               /   demoapp-deploy:80 (192.168.113.39:80,192.168.12.39:80)
Annotations:   kubernetes.io/ingress.class: nginx
Events:
  Type    Reason  Age                   From                      Message
  ----    ------  ----                  ----                      -------
  Normal  Sync    113s (x3 over 6h36m)  nginx-ingress-controller  Scheduled for sync

• 创建tls自签证书

[root@k8s-master Ingress]# (umask 077); openssl  genrsa -out tls.key 2048
Generating RSA private key, 2048 bit long modulus
............................+++
.......................+++
e is 65537 (0x10001)
[root@k8s-master Ingress]# openssl req -new -x509 -key tls.key -out tls.crt -subj "/CN=www.ik8s.io" -days 365
[root@k8s-master Ingress]# ls
demoapp-ingress.yaml    deployment-demo.yaml  tls.crt
deploy-externalIP.yaml  deploy.yaml           tls.key

• 创建Secret

[root@k8s-master Ingress]# kubectl create secret tls ik8s-tls --cert=./tls.crt --key=./tls.key
secret/ik8s-tls created

• 访问测试

[root@k8s-master Ingress]# curl -H  "Host:www.ik8s.io" 192.168.54.173   #308已经被重定向
<html>
<head><title>308 Permanent Redirect</title></head>
<body>
<center><h1>308 Permanent Redirect</h1></center>
<hr><center>nginx</center>
</body>
</html>

#通过https访问  提示证书无效不被信任
[root@k8s-master Ingress]# curl -H  "Host:www.ik8s.io" https://192.168.54.173 
curl: (60) Issuer certificate is invalid.
More details here: http://curl.haxx.se/docs/sslcerts.html

curl performs SSL certificate verification by default, using a "bundle"
 of Certificate Authority (CA) public keys (CA certs). If the default
 bundle file isn't adequate, you can specify an alternate file
 using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
 the bundle, the certificate verification probably failed due to a
 problem with the certificate (it might be expired, or the name might
 not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use
 the -k (or --insecure) option.

• 忽略风险 访问成功

[root@k8s-master Ingress]# curl -k -H  "Host:www.ik8s.io" https://192.168.54.173  
iKubernetes demoapp v1.1 !! ClientIP: 192.168.113.37, ServerName: deployment-demo-867c7d9d55-9lnpq, ServerIP: 192.168.12.39!

示例3：为dashboard 添加ingress

https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/

[root@k8s-master Ingress]# cat ingress-kubernetes-dashboard.yaml 
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: dashboard
  annotations:
    kubernetes.io/ingress.class: "nginx" #指定控制器
    ingress.kubernetes.io/ssl-passthrough: "true"   #tcp代理 因为后端dashboard必须通过https访问  这里通过4层转发直接转发到后端Pod
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS" #后端直接通过https协议访问
    nginx.ingress.kubernetes.io/rewrite-target: /$2 #重写标记 path:/dashboard(/|$)(.*) 这里的第2部分
  namespace: kubernetes-dashboard
spec:  #这里没有配置host 相当于*号通配所有主机 
  rules:
  - http:
      paths:
      - path: /dashboard(/|$)(.*)
        backend:
          serviceName: kubernetes-dashboard
          servicePort: 443

[root@k8s-master Ingress]# kubectl apply -f ingress-kubernetes-dashboard.yaml 
Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress
ingress.extensions/dashboard created

[root@k8s-master Ingress]# kubectl describe ingress dashboard -n kubernetes-dashboard
Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress
Name:             dashboard
Namespace:        kubernetes-dashboard
Address:          192.168.4.171
Default backend:  default-http-backend:80 (<error: endpoints "default-http-backend" not found>)
Rules:
  Host        Path  Backends
  ----        ----  --------
  *           
              /dashboard(/|$)(.*)   kubernetes-dashboard:443 (192.168.51.64:8443)  #后端pod
Annotations:  ingress.kubernetes.io/ssl-passthrough: true
              kubernetes.io/ingress.class: nginx
              nginx.ingress.kubernetes.io/backend-protocol: HTTPS
              nginx.ingress.kubernetes.io/rewrite-target: /$2
Events:
  Type    Reason  Age                   From                      Message
  ----    ------  ----                  ----                      -------
  Normal  Sync    103s (x2 over 2m41s)  nginx-ingress-controller  Scheduled for sync

• 访问测试

注意：https://192.168.54.173/dashboard/ 一定要带上最后的/ $2为/后面部分 不然无法访问

示例4：longhorn添加ingress-nginx basic认证

参考官方文档

https://longhorn.io/docs/1.2.0/deploy/accessing-the-ui/longhorn-ingress/

• 默认longhorn没有登录认证暴露到公网会存在风险 首先添加basic认证

[root@k8s-master Ingress]# kubectl get pod -n longhorn-system 
NAME                                        READY   STATUS    RESTARTS   AGE
....
longhorn-manager-cc8sp                      1/1     Running   0          149m
longhorn-manager-fs5tx                      1/1     Running   2          149m
longhorn-manager-vwbzn                      1/1     Running   1          149m
longhorn-ui-79f8976fbf-c44ct                1/1     Running   1          149m
[root@k8s-master Ingress]# kubectl get svc  -n longhorn-system 
NAME                TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)     AGE
csi-attacher        ClusterIP   10.108.190.205   <none>        12345/TCP   142m
csi-provisioner     ClusterIP   10.99.216.181    <none>        12345/TCP   142m
csi-resizer         ClusterIP   10.96.161.192    <none>        12345/TCP   141m
csi-snapshotter     ClusterIP   10.101.216.72    <none>        12345/TCP   141m
longhorn-backend    ClusterIP   10.108.67.31     <none>        9500/TCP    149m
longhorn-frontend   ClusterIP   10.107.71.176    <none>        80/TCP      149m

[root@k8s-master Ingress]# USER=user.com; PASSWORD=passwd.com; echo "${USER}:$(openssl passwd -stdin -apr1 <<< ${PASSWORD})" >> auth
[root@k8s-master Ingress]# ls
auth                  deploy-externalIP.yaml  deploy.yaml                        tls.crt
demoapp-ingress.yaml  deployment-demo.yaml    ingress-kubernetes-dashboard.yaml  tls.key

[root@k8s-master Ingress]# kubectl -n longhorn-system create secret generic basic-auth --from-file=authsecret/basic-auth created

[root@k8s-master Ingress]# cat longhorn-ui-ingress.yaml 
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: longhorn-ingress
  namespace: longhorn-system
  annotations:
    kubernetes.io/ingress.class: "nginx"   #指定控制器
    # type of authentication
    nginx.ingress.kubernetes.io/auth-type: basic  #认证类型
    # prevent the controller from redirecting (308) to HTTPS
    nginx.ingress.kubernetes.io/ssl-redirect: 'false'     #http通信
    # name of the secret that contains the user/password definitions
    nginx.ingress.kubernetes.io/auth-secret: basic-auth    #secret名称
    # message to display with an appropriate context why the authentication is required
    nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required '   #输入提示
    # custom max body size for file uploading like backing image uploading
    nginx.ingress.kubernetes.io/proxy-body-size: 10000m
    nginx.ingress.kubernetes.io/rewrite-target: /$2 
spec:
  rules:
  - http:
      paths:
      - pathType: Prefix
        path: /longhorn(/|$)(.*)
        backend:
          service:
            name: longhorn-frontend
            port:
              number: 80

[root@k8s-master Ingress]# kubectl apply -f longhorn-ui-ingress.yaml 
ingress.networking.k8s.io/longhorn-ingress configured

• 访问 http://IP/longhorn/ #最后的 "/" 一定要加

• 以下图片IP 重新部署后的服务IP