Kubernetes——对外服务之Ingress

Posted 2022-04-11 封玖FJ

Ingress简介

service的作用

1. 对集群内部，它不断跟踪pod的变化，更新endpoint中对应pod的对象，提供了ip不断变化的pod的服务发现机制
2. 对集群外部，他类似负载均衡器，可以在集群内外部对pod进行访问

外部访问k8s集群内的服务

1. NodePort: 测试环境使用还行，当有几十上百的服务在集群中运行时，NodePort的端口管理就是个灾难
2. LoadBalancer: 受限于云平台，且通常在云平台部署LoadBalancer还需要额外的费用
3. Ingress: 可以简单理解为service的service，它其实就是一组基于域名和URL路径，把用户的请求转发到一个或多个service的规则

Ingress组成

1. ingress

1. ingress是一个API对象，通过yaml文件来配置，ingress对象的作用是定义请求如何转发到service的规则，可以理解为配置模板
2. ingress通过http或https暴露集群内部service，给service提供外部URL、负载均衡、SSL/TLs能力以及基于域名的反向代理。ingress要依靠ingress-controller来具体实现以上功能

2 ingress-controller

1. ingress-controller是具体实现反向代理及负载均衡的程序，对ingress定义的规则进行解析，根据配置的规则来实现请求转发
2. ingress -controller并不是kes自带的组件，实际上ingress-controller只是一个统称，用户可以选择不同的ingress-controller实现，目前，由k8s维护的ingress-controller只有google云的ccz与ingress-nginx两个，其他还有很多第三方维护的ingres-controller，具体可以参考官方文档。但是不管哪一种ingress-controller，实现的机制都大同小异，只是在具体配置上有差异

3. 一般来说，ingress-controller的形式都是一个pod,里面跑着daemon程序和反向代理程序。daemcn负责不断监控集群的变化，根据ingress对象生成配置并应用新配置到反向代理，比如ingress -nginx就是动态生成nginx配置，动态更新upstrea，并在需要的时候reloada程序应用新配置。为了方便，后面的例子都以k8s官方维护的ingress-nginx为例

4. Ingress-Nginx github 地址:https://github.com/kubernetes/ingress-nginx
   Ingress-Nginx官方网站:https:/kubernetes.github.io/ingress-nginx/

总结: ingress-controller才是负责具体转发的组件，通过各种方式将它暴露在集群入口，外部对集群的请求流量会先到

Ingress工作原理

1. ingress-controller通过和 kubernetes APIServer 交互，动态的去感知集群中ingress规则变化
2. 然后读取它，按照自定义的规则，规则就是写明了哪个域名对应哪个service，生成一段nginx配置
3. 再写到nginx-ingress-controller的pod里，这个ingress-controller的pod里运行着一个nginx服务，控制器会把生成的nginx配置写入/etc/nginx.conf文件中

4. 然后reload一下使配置生效。以此达到域名区分配置和动态更新的作用

   

部署nginx-ingress-controller

1. 部署ingress-controller pod及相关资源

1.mkdir /opt/ingress
2.cd /opt/ingress
==========================================================
官方下载地址：
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.25.0/deploy/static/mandatory.yaml

上面可能无法下载，可用国内的gitee
3.wget https://gitee.com/mirrors/ingress-nginx/raw/nginx-0.25.0/deploy/static/mandatory.yaml

wget https://gitee.com/mirrors/ingress-nginx/raw/nginx-0.30.0/deploy/static/mandatory.yaml

#mandatory.yaml文件中包含了很多资源的创建，包括namespace、configMap、role，ServiceAccount等等所有部署ingress-controller需要的资源

2. 修改clusterRole资源配置

vim mandatory.yaml
....
- apiGroups:
    - ""
  resources:
    -services
  verbs:
    - get
    - list
    - watch
- apiGroups:
    - "extensions"
    - "networking.k8s.io"#增加（0.25版本）
  resources:
    - ingresses
  verbs:
    - get
    - list
    - watch
- apiGroups:
    - ""
  resources:
    - events
  verbs:
    - create
    - patch
- apiGroups:
    - "extensions"
    - "networking.k8s.io"#增加（o.25版本)
  resources:
    - ingresses/ status
  verbs:
    - update

ingress暴露服务的方式

1. Deployment+LoadBalancer模式的Service

如果要把ingress部署在公有云，那用这种方式比较合适。用Deployment部署ingress-controller，创建一个type为 LoadBalancer的 service关联这组pod。大部分公有云，都会为 LoadBalancer的 service自动创建一个负载均衡器，通常还绑定了公网地址。只要把域名解析指向该地址，就实现了集群服务的对外暴露

2. DaemonSet+HostNetwork+nodeselector

用DaemonSet结合nodeselector来部署ingress-controller到特定的node 上，然后使用Hostiletwork直接把该pod与宿主机node的网络打通，直接使用宿主机的80/433端口就能访问服务。这时，ingress-controller所在的node机器就很类似传统架构的边缘节点，比如机房入口的nginx服务器。该方式整个请求链路最简单，性能相对NodePort模式更好。缺点是由于直接利用宿主机节点的网络和端口，一个node只能部署一个ingress-controller pod。比较适合大并发的生产环境使用

3. Deployment+NodePort模式的Service

1)同样用deployment模式部署ingres-controller，并创建对应的服务，但是type为NodePort。这样，ingress就会暴露在集群节点ip的特定端口上
2)由于nodeport暴露的端口是随机端口，一般会在前面再搭建一套负载均衡器来转发请求。该方式一般用于宿主机是相对固定的环境ip地址不变的场景
3)NodePort方式暴露ingress虽然简单方便，但是NodePort多了一层NAT，在请求量级很大时可能对性能会有一定影响

采用方式二:DaemonSet+HostNetwork+nodeselector

1. 指定nginx-ingress-controller运行在node02节点

kubectl label node node02 ingress=true

kubectl get nodes --show-labels

2. 修改Deployment为Daemonset,指定节点运行，并开启 hostNetwork

vim mandatory.yaml
...
apiversion: apps/vl
kind: Daemonset   #修改kind
...
hostNetwork: true  #使用主机网络
nodeSelector:
  ingress: "true"   #选择节点运行
...

3. 所有node节点上传nginx-ingress-controller镜像压缩包ingree.contro.tar.gz.到/opt/ingress目录，并解压和加载镜像

mkdir /opt/ingress
cd /opt/ingress
tar zxvf ingree.contro.tar.gz
docker load -i ingree.contro.tar

4. 启动nginx-ingress-controller

#主节点
kubectl apply -f mandatory.yaml

kubectl get pod -n ingress-nginx -o wide

到node02节点查看
netstat -natp | grep nginx
==========================================================
由于配置了hostnetwork， nginx已经在 node主机本地监听团/443/8181端口。其中 8181 是nginx-controller默认配置的一个defaultbackend (Ingress资源没有匹配的 rule 对象时，流量就会被导向这个default backend)
这样，只要访问 node主机有公网 TP，就可以直接映射域名来对外网暴露服务了。如果要nginx高可用的话，可以在多个node39上部署，并在前面再搭建一套LVS+keepalive做负载均衡。

5. 创建ingress规则

1) 创建一个deployment和svc

在主节点创建
vim service-nginx.yaml
==========================================================
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    run: nginx-app
  name: nginx-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx-app
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata :
  name: nginx-service
spec:
  type: ClusterIP
  ports :
  - port: 7777
    targetPort: 80
  selector :
   app: nginx
==========================================================
kubectl apply -f service-nginx.yaml

kubectl get pod,svc

2) 创建ingress

vim ingress-1.yaml
==========================================================
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-ingress
spec:
  rules:
  - host: www.lzc.com
    http:
      paths:
      - path: /
        backend:
          serviceName: nginx-service  #指定你创建的svc的名称
          servicePort: 80
==========================================================
kubectl apply -f ingress-1.yaml

kubectl get pod,svc,ingress

6. 做端口映射并访问测试

echo 192.168.10.30 www.lzc.com >> /etc/hosts

curl www.lzc.com

7. 查看nginx-ingress-controller

kubectl get pod -n ingress-nginx -o wide

kubectl exec -it nginx-ingress-controller-k5vvf  -n ingress-nginx bash

采用方式三：Deployment+NodePort模式的Service

1. 下载nginx-ingress-controller和ingress-nginx暴露端口配置文件

在主节点
mkdir /opt/ingress-nodeport
cd /opt/ingress-nodeport

官方下载地址：
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.30.0/deploy/static/mandatory.yaml
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.30.0/deploy/static/provider/baremetal/service-nodeport.yaml

国内 gitee 资源地址：
wget https://gitee.com/mirrors/ingress-nginx/raw/nginx-0.30.0/deploy/static/mandatory.yaml
wget https://gitee.com/mirrors/ingress-nginx/raw/nginx-0.30.0/deploy/static/provider/baremetal/service-nodeport.yaml

2. 在所有node节点上传镜像包ingress-controller-0.30.0.tar到/opt/ingress-nodeport目录，并加载镜像

在所有node节点
mkdir /opt/ingress-nodeport
cd /opt/ingress-nodeport
tar zxvf ingree.contro-0.30.0.tar.gz
docker load -i ingree.contro-0.30.0.tar

3. 启动nginx-ingress-controller

kubectl apply -f mandatory.yaml
kubectl apply -f service-nodeport.yaml

4. 创建deployment、service和ingress的yaml资源

vim ingress-nginx.yaml 
==========================================================
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-app
spec:
  replicas: 2
  template:
    metadata:
      labels:
        name: nginx
    spec:
      containers:
        - name: nginx
          image: nginx
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-svc
spec:
  ports:
    - port: 80
      targetPort: 80
      protocol: TCP
  selector:
    name: nginx
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-test
spec:
  rules:
    - host: www.lzc111.com
      http:
        paths:
        - path: /
          backend:
            serviceName: nginx-svc
            servicePort: 80
==========================================================kubectl apply -f ingress-nginx.yaml                       
kubectl get pod,svc,ingress -owide

5. 做端口映射并访问测试

echo 192.168.10.30 www.lzc111.com >> /etc/hosts

curl www.lzc111.com

ingress http代理访问虚拟主机

mkdir /opt/ingress-nodeport/vhost
cd /opt/ingress-nodeport/vhost
==========================================================
#创建虚拟主机1资源
vim demo1.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: deployment1
spec:
  replicas: 2
  template:
    metadata:
      labels:
        name: nginx1
    spec:
      containers:
        - name: nginx1
          image: nginx
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: svc-1
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    name: nginx1
  type: ClusterIP
==========================================================
#创建虚拟主机2资源
vim demo2.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: deployment2
spec:
  replicas: 2
  template:
    metadata:
      labels:
        name: nginx2
    spec:
      containers:
        - name: nginx2
          image: nginx
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: svc-2
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    name: nginx2
  type: ClusterIP
==========================================================
创建ingress资源
vim ingress-nginx.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress1
spec:
  rules:
    - host: www1.lzc.com
      http:
        paths:
        - path: /
          backend:
            serviceName: svc-1
            servicePort: 80
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress2
spec:
  rules:
    - host: www2.gxd.com
      http:
        paths:
        - path: /
          backend:
            serviceName: svc-2
            servicePort: 80
==========================================================
kubectl apply -f demo1.yaml
kubectl apply -f demo2.yaml
kubectl apply -f ingress-nginx.yaml
kubectl get pod,svc,ingress

echo 192.168.10.30 www1.lzc.com  >> /etc/hosts
echo 192.168.10.30 www2.lzc.com  >> /etc/hosts
curl www1.lzc.com:31396
curl www2.lzc.com:31396

ingress https代理访问

1. 创建工作目录

mkdir /opt/ingress-nodeport/https
cd /opt/ingress-nodeport/https

2.创建ssl证书

openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout tls.key -out tls.crt -subj  "/CN=nginXsvc/O=nginxsvc"

3. 创建secret资源进行存储

kubectl create secret tls tls-secret --key tls.key --cert tls.crt

kubectl get secret

kubectl describe secret tls-secret

4. 创建deployment、service和ingress的yaml资源

vim demo3.yaml 
==========================================================
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-app
spec:
  replicas: 2
  template:
    metadata:
      labels:
        name: nginx
    spec:
      containers:
        - name: nginx
          image: nginx
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: svc-3
spec:
  ports:
    - port: 80
      targetPort: 80
      protocol: TCP
  selector:
    name: nginx
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress3
spec:
  tls:
    - hosts: 
      - www.lzc222.com
      secretName: tls-secret
  rules: 
    - host: www.lzc222.com
      http:
        paths:
        - path: /
          backend:
            serviceName: svc-3
            servicePort: 80
==========================================================kubectl apply -f demo3.yaml                       
kubectl get pod,svc,ingress 

5. 做端口映射并访问测试

echo 192.168.10.30 www.lzc222.com >> /etc/hosts

在浏览器访问 https://www.lzc222.com:31067
点击高级选项，确认安全例外即可

nginx进行BasicAuth（访问前输入用户和密码）

1. 创建工作目录

mkdir /opt/ingress-nodeport/basic-auth
cd /opt/ingress-nodeport/basic-auth

2. 生成用户密码文件，创建secret资源进行存储

yum install -y httpd
htpasswd -c auth lzc
kubectl create secret generic basic-auth --from-file=auth
kubectl get secret
kubectl describe secret basic-auth

3. 创建ingress资源

//具体详细设置方法可参考官网https://kubernetes.github.io/ingress-nginx/examples/auth/basic/

vim ingress-auth.yaml
==========================================================
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-auth
  annotations:
    #设置认证类型basic
    nginx.ingress.kubernetes.io/auth-type: basic
    #设置secret资源名称basic-auth
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    #设置认证窗口提示信息
    nginx.ingress.kubernetes.io/auth-realm: Authentication Required - lzc
spec:
  rules:
  - host: auth.lzc.com
    http:
      paths:
      - path: /
        backend:
          serviceName: svc-2  #之前指定创建过的svc
          servicePort: 80
==========================================================
kubectl apply -f ingress-auth.yaml 
kubectl get ingress

4. 做端口映射并访问测试

echo 192.168.10.30 auth.lzc.com >> /etc/hosts

在浏览器访问 http://auth.lzc.com:31396

nginx进行重写

1. 配置说明

nginx.ingress.kubernetes.io/rewrite-target:<字符串>#必须重定向流量的目标URI
nginx.ingress . kubernetes.io/ssl-redirect:<布尔值>指示位置部分是否仅可访问sSL(当Ingress包含证书时，默认为true)nginx.ingress . kubernetes.io/force-ssl-redirect:<布尔值>#即使Ingress未启用rLS，也强制重定向到HTTPS
nginx.ingress .kubernetes.io/app-root:<字符串>#定义controller必须重定向的应用程序根，如果它在/上下文中·nginx.ingress, kubernetes.io/use-regex:<布尔值>#指示Ingress.上定义的路径是否使用正则表达式

2. 编写yaml文件

vim ingress-rewrite.yaml
==========================================================
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-rewrite
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: http://auth.lzc.com:31396
spec:
  rules:
  - host: rewrite.lzc.com
    http:
      paths:
      - path: /
        backend:
          serviceName: ggggg  #由于rewrite.lzc.com只是用于跳转不需要真实站点存在，因此svc资源名称可随意定义
          servicePort: 1111 
==========================================================
kubectl apply -f ingress-rewrite.yaml
kubectl get ingress

3. 做端口映射并访问测试

echo 192.168.10.30 rewrite.lzc.com >> /etc/hosts

在浏览器访问 http://rewrite.lzc.com