K8s中使用traefik（基础）

2023-09-21 约 1895 字预计阅读 4 分钟

简介

Traefik是一个为了让部署微服务更加便捷而诞生的现代HTTP反向代理、负载均衡工具。它支持多种后台 (Docker, Swarm, Kubernetes, Marathon, Mesos, Consul, Etcd, Zookeeper, BoltDB, Rest API, file…) 来自动化、动态的应用它的配置文件设置。

核心概念：当启动Traefik时，需要定义entrypoints，然后通过entrypoints的路由来分析传入的请求，来查看他们是否是一组规则匹配，如果匹配，则路由可能将请求通过一系列的转换过来在发送到服务上去。

Providers用来自动发现平台上的服务，可以是编排工具、容器引擎
Entrypoints监听传入的流量，是网络的入口点，定义了接受请求的端口(HTTP或者TCP)
Routers分析请求(host,path,headers,SSL等)，负责将传入的请求连接到可以处理这些请求的服务上去
Service将请求转发给应用，负责配置如何最终将处理传入请求的实际服务
Middlewares中间件，用来修改请求或者根据请求来做出判断，中间件被附件到路由上，是一种在请求发送到服务之前调整请求的一种方法

安装

使用helm在k8s中安装

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helm repo add traefik https://helm.traefik.io/traefik
helm repo update
helm install --namespace=traefik --create-namespace traefik traefik/traefik

暴露dashboard服务

使用port-forward临时暴露：

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kubectl port-forward $(kubectl get pods --selector "app.kubernetes.io/name=traefik" --output=name -n traefik) -n traefik --address 0.0.0.0 9000:9000

使用IngressRoute暴露：

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# traefik-dashboard.yaml
apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: traefik-dashboard
  namespace: traefik
spec:
  entryPoints:
    - web
  routes:
    - match: Host(`traefik.nblh.local`) && (PathPrefix(`/dashboard`) || PathPrefix(`/api`))
      kind: Rule
      services:
        - name: api@internal
          kind: TraefikService

Host为你的域名，写好配置清单之后kubectl apply一下就好了. 最后打开浏览器访问 http://traefik.nblh.local:39281/dashboard/ 即可（注意dashboard后面还有个/不然访问不了）. 上面的39281为traefik NodePort的映射端口，这里要换成实际自己的（没有LoadBlancer的话）.

docker中运行

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docker run -d -p 8080:8080 -p 80:80 \ -v $PWD/traefik.yml:/etc/traefik/traefik.yml traefik:v2.10

使用场景

路由

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# 下面以官方whoami为例，稍作改动
kind: Deployment
apiVersion: apps/v1
metadata:
  name: whoami
  labels:
    app: whoami

spec:
  replicas: 1
  selector:
    matchLabels:
      app: whoami
  template:
    metadata:
      labels:
        app: whoami
    spec:
      containers:
        - name: whoami
          image: traefik/whoami
          ports:
            - name: web
              containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: whoami

spec:
  ports:
    - name: web
      port: 80
      targetPort: web

  selector:
    app: whoami
# ---
# apiVersion: networking.k8s.io/v1
# kind: Ingress
# metadata:
#   name: whoami-ingress
# spec:
#   rules:
#   - host: whoami.nblh.local
#     http:
#       paths:
#       - path: /whoami
#         pathType: Prefix
#         backend:
#           service:
#             name: whoami
#             port:
#               name: web
---
apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: whoami-example
  namespace: traefik
spec:
  entryPoints:
    - web
  routes:
  - match: Host(`whoami.nblh.local`) && PathPrefix(`/`)
    kind: Rule
    services:
    - name: whoami
      port: 80
      kind: Service
      namespace: traefik

应用清单文件并查看结果：

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# 应用
kubectl apply -f whoami.yaml
# describe看一下
kdn traefik ingressroutes.traefik.io whoami-example
Name:         whoami-example
Namespace:    traefik
Labels:       <none>
Annotations:  <none>
API Version:  traefik.io/v1alpha1
Kind:         IngressRoute
Metadata:
  Creation Timestamp:  2023-09-21T06:04:42Z
  Generation:          1
  Resource Version:    5659968
  UID:                 cb2ada76-9f1a-45aa-9fa2-541b5894409c
Spec:
  Entry Points:
    web
  Routes:
    Kind:   Rule
    Match:  Host(`whoami.nblh.local`) && PathPrefix(`/`)
    Services:
      Kind:       Service
      Name:       whoami
      Namespace:  traefik
      Port:       80
Events:           <none>

打开dashboard可以看到新创建的route：打开浏览器访问 whoami.nblh.local:39281：

反向代理

下面以反代tcp MySQL服务为例。

默认配置文件下，只有traefik(9000)、web(8000)、websecure(8443)以及metrics(9100)开放，如果想要反代MySQL tcp又想自定义端口的话，需要单独在配置文件中进行配置，下面以helm 安装的traefik为例：

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# 修改values.yaml的port配置段，添加MySQL的entrypoint
...
ports:
  mysql:
    port: 13306
    expose: true
    exposedPort: 3306
    protocol: TCP
  traefik:
    port: 9000
...

修改完成之后发布helm chart：

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helm upgrade -n traefik traefik -f values.yaml  . 
# describe检查一下
kdsvcn traefik traefik
Name:                     traefik
Namespace:                traefik
Labels:                   <none>
Annotations:              <none>
Selector:                 app.kubernetes.io/instance=traefik-traefik,app.kubernetes.io/name=traefik
Type:                     NodePort
IP Family Policy:         SingleStack
IP Families:              IPv4
IP:                       10.106.204.239
IPs:                      10.106.204.239
Port:                     web  8000/TCP
TargetPort:               8000/TCP
NodePort:                 web  39281/TCP
Endpoints:                10.96.0.222:8000
Port:                     websecure  8443/TCP
TargetPort:               8443/TCP
NodePort:                 websecure  35127/TCP
Endpoints:                10.96.0.222:8443
Port:                     mysql  13306/TCP
TargetPort:               13306/TCP
NodePort:                 mysql  37197/TCP
Endpoints:                10.96.0.222:13306
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>

可以看到MySQL的13306已经映射到NodePort的37197端口. 2. 编写反代tcp的清单文件：

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# traefik-tcp-mysql.yaml
apiVersion: traefik.io/v1alpha1
kind: IngressRouteTCP
metadata:
  name: mysql-ingressroutetcp
  namespace: default
spec:
  entryPoints:
    - mysql
  routes:
    - match: HostSNI(`*`)
      services:
        - name: mysql-svc      # 这里的mysql-svc是我集群中的一个无头服务.
          namespace: default
          port: 3306

应用该清单文件：kubectl apply -f traefik-tcp-mysql.yaml. 3. 检查与测试：

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# describe 看一下
kdn default ingressroutetcps.traefik.io mysql-ingressroutetcp
Name:         mysql-ingressroutetcp
Namespace:    default
Labels:       <none>
Annotations:  <none>
API Version:  traefik.io/v1alpha1
Kind:         IngressRouteTCP
Metadata:
  Creation Timestamp:  2023-09-21T06:26:23Z
  Generation:          1
  Resource Version:    5663676
  UID:                 52b46037-137e-444d-b90e-158b98d584b2
Spec:
  Entry Points:
    mysql
  Routes:
    Match:  HostSNI(`*`)
    Services:
      Name:       mysql-svc
      Namespace:  default
      Port:       3306
Events:           <none>

在dashboard中检查：现在就可以使用MySQL客户端进行连接啦，比如使用mycli工具进行连接：

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 mycli -h172.19.82.158 -P37197 -uroot
MySQL 5.7.43
mycli 1.27.0
Home: http://mycli.net
Bug tracker: https://github.com/dbcli/mycli/issues
Thanks to the contributor - KITAGAWA Yasutaka
MySQL root@172.19.82.158:(none)> select version();
+------------+
| version()  |
+------------+
| 5.7.43-log |
+------------+

1 row in set
Time: 0.026s

Done.

参考链接

Traefik Installation Documentation - Traefik

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