TreeviewCopyright © Pengfei Ni all right reserved, powered by aleen42

Traefik ingress

Traefik是一个开源的反向代理和负载均衡工具,它监听后端的变化并自动更新服务配置。

主要功能包括

  • Golang编写,部署容易
  • 快(nginx的85%)
  • 支持众多的后端(Docker, Swarm, Kubernetes, Marathon, Mesos, Consul, Etcd等)
  • 内置Web UI、Metrics和Let’s Encrypt支持,管理方便
  • 自动动态配置
  • 集群模式高可用

Ingress简介

简单的说,ingress就是从kubernetes集群外访问集群的入口,将用户的URL请求转发到不同的service上。Ingress相当于nginx、apache等负载均衡方向代理服务器,其中还包括规则定义,即URL的路由信息,路由信息得的刷新由Ingress controller来提供。

Ingress Controller 实质上可以理解为是个监视器,Ingress Controller 通过不断地跟 kubernetes API 打交道,实时的感知后端 service、pod 等变化,比如新增和减少 pod,service 增加与减少等;当得到这些变化信息后,Ingress Controller 再结合下文的 Ingress 生成配置,然后更新反向代理负载均衡器,并刷新其配置,达到服务发现的作用。

部署Traefik

介绍traefik

Traefik是一款开源的反向代理与负载均衡工具。它最大的优点是能够与常见的微服务系统直接整合,可以实现自动化动态配置。目前支持Docker, Swarm, Mesos/Marathon, Mesos, Kubernetes, Consul, Etcd, Zookeeper, BoltDB, Rest API等等后端模型。

以下配置文件可以在Traefik GitHub仓库中的examples/k8s/traefik-rbac.yaml找到。

创建ingress-rbac.yaml

将用于service account验证。

---
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
kubectl apply -f https://raw.githubusercontent.com/containous/traefik/master/examples/k8s/traefik-rbac.yaml

创建Depeloyment

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
---
kind: Deployment
apiVersion: extensions/v1beta1
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
  labels:
    k8s-app: traefik-ingress-lb
spec:
  replicas: 1
  selector:
    matchLabels:
      k8s-app: traefik-ingress-lb
  template:
    metadata:
      labels:
        k8s-app: traefik-ingress-lb
        name: traefik-ingress-lb
    spec:
      serviceAccountName: traefik-ingress-controller
      terminationGracePeriodSeconds: 60
      containers:
      - image: traefik
        name: traefik-ingress-lb
        args:
        - --web
        - --kubernetes
---
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
  type: NodePort
# 使用deployment部署
kubectl apply -f https://raw.githubusercontent.com/containous/traefik/master/examples/k8s/traefik-deployment.yaml
# 也可以使用daemonset来部署
# kubectl apply -f https://raw.githubusercontent.com/containous/traefik/master/examples/k8s/traefik-ds.yaml

注意我们这里用的是Deploy类型,没有限定该pod运行在哪个主机上。Traefik的端口是8580。

创建名为traefik-ingress的ingress,文件名traefik.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: traefik-ingress
spec:
  rules:
  - host: traefik.nginx.io
    http:
      paths:
      - path: /
        backend:
          serviceName: nginx
          servicePort: 80
  - host: traefik.frontend.io
    http:
      paths:
      - path: /
        backend:
          serviceName: frontend
          servicePort: 80

这其中的backend中要配置default namespace中启动的service名字。path就是URL地址后的路径,如traefik.frontend.io/path,service将会接受path这个路径,host最好使用service-name.filed1.filed2.domain-name这种类似主机名称的命名方式,方便区分服务。

根据你自己环境中部署的service的名字和端口自行修改,有新service增加时,修改该文件后可以使用kubectl replace -f traefik.yaml来更新。

Traefik UI

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: traefik-ui.nginx.io
    http:
      paths:
      - backend:
          serviceName: traefik-web-ui
          servicePort: 80

配置完成后就可以启动treafik ingress了。

kubectl create -f .

我查看到traefik的pod在172.20.0.115这台节点上启动了。

访问该地址http://172.20.0.115:8580/将可以看到dashboard。

kubernetes-dashboard

左侧黄色部分部分列出的是所有的rule,右侧绿色部分是所有的backend。

测试

在集群的任意一个节点上执行。假如现在我要访问nginx的"/"路径。

$ curl -H Host:traefik.nginx.io http://172.20.0.115/
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

如果你需要在kubernetes集群以外访问就需要设置DNS,或者修改本机的hosts文件。

在其中加入:

172.20.0.115 traefik.nginx.io
172.20.0.115 traefik.frontend.io

所有访问这些地址的流量都会发送给172.20.0.115这台主机,就是我们启动traefik的主机。

Traefik会解析http请求header里的Host参数将流量转发给Ingress配置里的相应service。

修改hosts后就就可以在kubernetes集群外访问以上两个service,如下图:

traefik-nginx

traefik-guestbook

参考文档

results matching ""

    No results matching ""