kubernetes中traefik部署安装

参考github项目地址https://github.com/containous/traefik

以下配置文件均可在https://github.com/containous/traefik/tree/master/examples/k8s找到

一部署

traefik 有两种部署方式，一种是通过deamonset形式，一种是通过deployment的形式。两个形式各有优势。

使用deployment,可伸缩性可以更好

使用deamonset，Single-Pod-per-Node。当节点加入群集时，DaemonSet会自动扩展到新节点。DaemonSet可以使用NET_BIND_SERVICE功能运行，这将允许它绑定到每个主机上的端口80/443 / etc。这将允许绕过kube-proxy，并减少流量跳跃。

首先创建rbac文件

##traefik-rbac.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

##traefik-ds.yaml

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
---
kind: DaemonSet
apiVersion: extensions/v1beta1
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
  labels:
    k8s-app: traefik-ingress-lb
spec:
  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
        ports:
        - name: http
          containerPort: 80
          hostPort: 80
        - name: admin
          containerPort: 8080
          hostPort: 8580
        securityContext:
          capabilities:
            drop:
            - ALL
            add:
            - NET_BIND_SERVICE
        args:
        - --api
        - --kubernetes
        - --logLevel=INFO
---
kind: Service
apiVersion: v1
metadata:
  name: traefik-ingress-service
  namespace: kube-system
spec:
  selector:
    k8s-app: traefik-ingress-lb
  ports:
    - protocol: TCP
      port: 80
      name: web
    - protocol: TCP
      port: 8080
      name: admin

deamonset的方式在配置文件中直接暴露机器的端口，由hostPort实现。访问时未使用的kube-proxy.

##traefik-deployment.yaml

---
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
        ports:
        - name: http
          containerPort: 80
        - name: admin
          containerPort: 8080
        args:
        - --api
        - --kubernetes
        - --logLevel=INFO
---
kind: Service
apiVersion: v1
metadata:
  name: traefik-ingress-service
  namespace: kube-system
spec:
  selector:
    k8s-app: traefik-ingress-lb
  ports:
    - protocol: TCP
      port: 80
      name: web
    - protocol: TCP
      port: 8080
      name: admin
  type: NodePort

deployment 的形式通过nodePort的形式暴露访问的端口。

创建

#创建rbac
kubectl create -f traefik-rbac.yaml

#创建服务
kubectl create -f traefik-ds.yaml
或者：
kubectl create -f traefik-deployment.yaml

二使用

创建到服务的Ingress

example：traefik web界面的访问

###traefik-ingress.yaml 

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: traefik-web-ui
  namespace: kube-system
spec:
  tls:
  - secretName: traefik-cert
  rules:
  - host: traefik-ui.k8s
    http:
      paths:
      - path: /
        backend:
          serviceName: traefik-ingress-service
          servicePort: 8080

注：此处的servicePort，可以是8080，也可以用name表示，如下：

###traefik-ingress2.yaml

---
apiVersion: v1
kind: Service
metadata:
  name: traefik-web-ui
  namespace: kube-system
spec:
  type: NodePort
  selector:
    k8s-app: traefik-ingress-lb
  ports:
  - name: web
    port: 80
    targetPort: 8080
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: traefik-web-ui
  namespace: kube-system
spec:
  rules:
  - host: traefik-ui.k8s
    http:
      paths:
      - path: /
        backend:
          serviceName: traefik-web-ui
          servicePort: web

三访问

将Ingress中的host 添加到本地的hosts文件中，形式： [节点IP host]

添加完成后即可通过浏览器访问。

四同一个域名，区分路径

example:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: cheeses
  annotations:
    traefik.frontend.rule.type: PathPrefixStrip
spec:
  rules:
  - host: cheeses.minikube
    http:
      paths:
      - path: /stilton
        backend:
          serviceName: stilton
          servicePort: http
      - path: /cheddar
        backend:
          serviceName: cheddar
          servicePort: http
      - path: /wensleydale
        backend:
          serviceName: wensleydale
          servicePort: http

traefik.frontend.rule.type: PathPrefixStrip 必须放在ingress的annotations中，才可以生效。

五访问调度

对于后台有多个副本的服务，默认的调度是：轮询调度。

可以在service的annotations中，配置traefik.ingress.kubernetes.io/load-balancer-method: drr

调度算法更改为动态轮询，根据每次调度到的服务动态调整权重。