kubernetes Ingress、Ingress controller

谁践踏了优雅 2023-07-20 10:37 128阅读 0赞

### 前言 ###

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### 四层负载均衡调度器service回顾 ###

使用四层负载均衡调度器service时，当客户端访问kubernetes集群内部的应用时，数据包走向如下面流程所示
    
    client--->nodeip:port--->service ip:port--->podip:port
    
    客户端-->node节点的ip:端口--->service的ip:端口--->pod的ip:端口

### 1.Ingress Controller ###

Ingress Controller是一个七层负载均衡调度器，客户端的请求先到达这个七层负载均衡调度器，由七层负载均衡器在反向代理到后端pod，常见的七层负载均衡器有nginx，traefik等，以我们熟悉的nginx为例，假如请求到达nginx，会通过upstream反向代理到后端pod，但是后端pod的ip地址是一直在变化的，因此在后端pod前需要加一个service，这个service只是起到分组的作用，那么我们upstream只需要填写service地址即可

nginx：需要手动加载配置文件  
traefik：定期自动加载配置文件，不需要手动干预，在微服务中几乎都会使用这种调度器

### 2.Ingress ###

官方：https://kubernetes.io/docs/concepts/services-networking/ingress/

ingress官网定义：ingress可以把进入到集群内部的请求转发到集群中的一些服务上，从而可以把服务暴漏到集群外部。Ingress 能把集群内Service 配置成外网能够访问的 URL，流量负载均衡，提供基于域名访问的虚拟主机等；ingress是k8s中的资源，当service关联的后端pod ip地址发生变化，就会把这些变化信息保存在ingress中，由ingress注入到七层负载均衡调度器ingress controller中，也就是把信息传入到七层负载均衡调度器的配置文件中，并且重新加载使配置生效，Ingress 可以用来规定 HTTP/S 请求应该被转发到哪个 Service 上，比如根据请求中不同的 Host 和 url 路径让请求落到不同的 Service 上

### 总结： ###

#### Ingress Controller： ####

Ingress Controller 可以理解为控制器，它通过不断的跟 Kubernetes API 交互，实时获取后端Service、Pod的变化，比如新增、删除等，结合Ingress 定义的规则生成配置，然后动态更新上边的 Nginx 或者trafik负载均衡器，并刷新使配置生效，来达到服务自动发现的作用。

#### Ingress： ####

Ingress 则是定义规则，通过它定义某个域名的请求过来之后转发到集群中指定的 Service。它可以通过 Yaml 文件定义，可以给一个或多个 Service 定义一个或多个 Ingress 规则。

### 3.七层调度器traefik ###

如果七层负载均衡调度器使用nginx，那么每次nginx配置文件修改之后，都需要重新reload才能生效，很不方便，如果使用traefik或者Envoy，可以每隔一定时间重新加载配置文件，不需要手动重新加载，对于这种微服务架构来说特别方便

### 4.使用七层负载均衡调度器的步骤 ###

（1）部署ingress controller，我们ingress controller使用的是traefik  
（2）创建service，用来分组pod  
（3）创建pod应用，可以通过控制器创建pod  
（4）创建ingress http，测试通过http访问  
（5）创建ingress https，测试通过https访问

### 5.客户端通过七层调度器访问后端pod的方式 ###

使用七层负载均衡调度器ingress controller时，当客户端访问kubernetes集群内部的应用时，数据包走向如下面流程所示：  
client—>Nodeip:port----->IngressController—>service—>pod  
![format_png][]\#\#\# 6.生成证书，在k8s集群的master节点操作  
（1）生成私钥  
openssl genrsa -out tls.key 2048  
（2）生成证书  
openssl req -new -x509 -key tls.key -out tls.crt -subj /C=CN/ST=Beijing/O=DevOps/CN=tomcat.lucky.com  
（3）生成secret  
kubectl create secret tls tomcat-ingress-secret --cert=tls.crt --key=tls.key

Secret 对象类型用来保存敏感信息，例如密码、OAuth 令牌和 ssh key。将这些信息放在 secret 中比放在 pod 的定义或者 docker 镜像中来说更加安全和灵活  
kubectl get secret 显示如下：  
![format_png 1][]

### 7.部署trafik，在k8s集群的master节点操作 ###

（1）生成openssl.cnf文件，这个文件里面把签发证书时需要的参数已经定义好了  
mkdir /root/test  
echo “”"

\[req\]

distinguished\_name = req\_distinguished\_name

prompt = yes

\[ req\_distinguished\_name \]

countryName = Country Name (2 letter code)

countryName\_value = CN

stateOrProvinceName = State or Province Name (full name)

stateOrProvinceName\_value = Beijing

localityName = Locality Name (eg, city)

localityName\_value = Haidian

organizationName = Organization Name (eg, company)

organizationName\_value = Channelsoft

organizationalUnitName = Organizational Unit Name (eg, section)

organizationalUnitName\_value = R & D Department

commonName = Common Name (eg, your name or your server’s hostname)

commonName\_value = \*.multi.io

emailAddress = Email Address

emailAddress\_value = xianchao@qq.com

“”" > /root/test/openssl.cnf

（2）生成一个证书  
openssl req -newkey rsa:4096 -nodes -config /root/test/openssl.cnf -days 3650 -x509 -out /root/test/tls.crt -keyout /root/test/tls.key  
（3）创建一个secret对象  
kubectl create -n kube-system secret tls ssl --cert /root/test/tls.crt --key /root/test/tls.key  
（4）部署traefik  
cat traefik.yaml

---
    kind: ClusterRole
    apiVersion: rbac.authorization.k8s.io/v1beta1
    metadata:
      name: traefik-ingress-controller
    rules:
      - apiGroups:
          - ""
        resources:
          - services
          - endpoints
          - secrets
        verbs:
          - get
          - list
          - watch
      - apiGroups:
          - extensions
        resources:
          - ingresses
        verbs:
          - get
          - list
          - watch
    ---
    kind: ClusterRoleBinding
    apiVersion: rbac.authorization.k8s.io/v1beta1
    metadata:
      name: traefik-ingress-controller
    roleRef:
      apiGroup: rbac.authorization.k8s.io
      kind: ClusterRole
      name: traefik-ingress-controller
    subjects:
    - kind: ServiceAccount
      name: traefik-ingress-controller
      namespace: kube-system
    ---
    apiVersion: v1
    kind: ServiceAccount
    metadata:
      name: traefik-ingress-controller
      namespace: kube-system
    ---
    kind: ConfigMap
    apiVersion: v1
    metadata:
      name: traefik-conf
      namespace: kube-system
    data:
      traefik.toml: |
        insecureSkipVerify = true
        defaultEntryPoints = ["http","https"]
        [entryPoints]
          [entryPoints.http]
          address = ":80"
          [entryPoints.https]
          address = ":443"
            [entryPoints.https.tls]
              [[entryPoints.https.tls.certificates]]
              CertFile = "/ssl/tls.crt"
              KeyFile = "/ssl/tls.key"
    ---
    kind: DaemonSet
    apiVersion: apps/v1
    metadata:
      name: traefik-ingress-controller
      namespace: kube-system
      labels:
        k8s-app: traefik-ingress-lb
    spec:
      selector:
          matchLabels:
            k8s-app: traefik-ingress-lb
            name: traefik-ingress-lb
      template:
        metadata:
          labels:
            k8s-app: traefik-ingress-lb
            name: traefik-ingress-lb
        spec:
          serviceAccountName: traefik-ingress-controller
          tolerations:
          - key: node-role.kubernetes.io/master
            effect: NoSchedule
          terminationGracePeriodSeconds: 60
          hostNetwork: true
          volumes:
          - name: ssl
            secret:
              secretName: ssl
          - name: config
            configMap:
              name: traefik-conf
          containers:
          - image: k8s.gcr.io/traefik:1.7.9
            name: traefik-ingress-lb
            ports:
            - name: http
              containerPort: 80
              hostPort: 80
            - name: admin
              containerPort: 8080
            securityContext:
              privileged: true
            args:
            - --configfile=/config/traefik.toml
            - -d
            - --web
            - --kubernetes
            volumeMounts:
            - mountPath: "/ssl"
              name: "ssl"
            - mountPath: "/config"
              name: "config"
    ---
    kind: Service
    apiVersion: v1
    metadata:
      name: traefik-ingress-service
    spec:
      selector:
        k8s-app: traefik-ingress-lb
      ports:
        - protocol: TCP
          port: 80
          name: web
        - protocol: TCP
          port: 8080
          name: admin
        - protocol: TCP
          port: 443
          name: https
      type: NodePort
    ---
    apiVersion: v1
    kind: Service
    metadata:
      name: traefik-web-ui
      namespace: kube-system
    spec:
      selector:
        k8s-app: traefik-ingress-lb
      ports:
      - port: 80
        targetPort: 8080
    ---
    apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      name: traefik-web-ui
      namespace: kube-system
      annotations:
        kubernetes.io/ingress.class: traefik
    spec:
      rules:
      - host: ingress.multi.io
        http:
          paths:
          - backend:
              serviceName: traefik-web-ui
              servicePort: 80

#### 把traefik镜像traefik\_1\_7\_9.tar.gz上传到k8s各个节点，手动解压： ####

docker load -i traefik\_1\_7\_9.tar.gz

#### 镜像地址： ####

链接：https://pan.baidu.com/s/1fTRc0J0iL7DeAH\_LNUkTQQ  
提取码：xg1z

#### kubectl apply -f traefik.yaml ####

（5）验证traefik部署是否成功  
kubectl get pods -n kube-system 显示如下，说明部署成功  
traefik-ingress-controller-g45th 1/1 Running 0 9m2s  
traefik-ingress-controller-lj9md 1/1 Running 0 9m2s

### 8.部署tomcat ###

cat tomcat-deploy.yaml

apiVersion: v1
    kind: Service
    metadata:
      name: tomcat
      namespace: default
    spec:
      selector:
        app: tomcat
        release: canary
      ports:
      - name: http
        targetPort: 8080
        port: 80
      - name: ajp
        targetPort: 8009
        port: 8009
    ---
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: tomcat-deploy
      namespace: default
    spec:
      replicas: 3
      selector:
        matchLabels:
          app: tomcat
          release: canary
      template:
        metadata:
          labels:
            app: tomcat
            release: canary
        spec:
          containers:
          - name: myapp
            image: tomcat:8.5-jre8-alpine
            ports:
            - name: http
              containerPort: 8080
            - name: ajp
              containerPort: 8009

kubectl apply -f tomcat-deploy.yaml  
kubectl get pods 显示如下，说明部署成功  
tomcat-deploy-59664bcb6f-5z4nn 1/1 Running 0 20s  
tomcat-deploy-59664bcb6f-cgjbn 1/1 Running 0 20s  
tomcat-deploy-59664bcb6f-n4tqq 1/1 Running 0 20s

### 9.部署tomcat http ###

cat ingress-tomcat.yaml

apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      name: ingress-tomcat
      namespace: default
      annotations:
        kubernetes.io/ingress.class: "traefik"
    spec:
      rules:
      - host: tomcat.lucky.com
        http:
          paths:
          - path:
            backend:
              serviceName: tomcat
              servicePort: 80

kubectl apply -f ingress-tomcat.yaml

### 10.部署tomcat https ###

cat ingress-tomcat-tls.yaml

apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      name: ingress-tomcat-tls
      namespace: default
      annotations:
         kubernetes.io/ingress.class: traefik
    spec:
      tls:
      - hosts:
        - tomcat.lucky.com
        secretName: tomcat-ingress-secret
      rules:
      - host: tomcat.lucky.com
        http:
          paths:
          - path:
            backend:
              serviceName: tomcat
              servicePort: 80

kubectl apply -f ingress-tomcat-tls.yaml

kubectl get ingress

显示如下：  
NAME HOSTS ADDRESS PORTS AGE  
ingress-tomcat tomcat.lucky.com 80 103s  
ingress-tomcat-tls tomcat.lucky.com 80, 443 8s

11.配置自己电脑的hosts文件

192.168.0.16 tomcat.lucky.com

12.在浏览器访问：

https://tomcat.lucky.com:443

或者http://tomcat.lucky.com

可看到如下界面，说明https配置成功  
![format_png 2][]

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微信：luckylucky421302

![format_png 4][]

![format_png 5][]

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