kubernetes常用资源对象ingress

我们前面介绍过用Service做集群代理，Service一般情况下只作用于内部Pod的代理调度，就算有NodePort类型，其访问节点相对复杂，流程大概如下：

但是我们知道，如果只指定一个NodeIP，随着业务量增大，这个Node的压力就会很大，所以我们可能会在前端再加一个代理，代理几个Node，比如我们在前端加一个NG，流程如下：



在应用小的情况下，这种架构虽然调度复杂，但是也可以使用，但是如果有大量应用，这种管理就非常麻烦，因为 我们要管理大量的NodePort，这个时候使用Ingress就非常方便。


再则，Service的转发不论是iptables还是ipvs，都是4层的，但是在实际中基本都https请求，https是7层，4层是没办法对起进行SSL校验的，如果我们是第二幅流程图，我们可以在前置NG上配置SSL，但是如果我们是第一幅图的流程，我们只能在Pod上配置SSL，因为Service上是无法进行校验，那么就会出现一个问题，SSL的校验是很耗资源的，我们的客户端访问Pod，如果Pod非常多并且访问模式是轮询，那么每访问一次就要做一次SSL校验，这就非常不科学，我们就只有用类似于第二副图的架构，Ingress可以很完美的解决这种问题。

一、Ingress

流程图如上，其中Ingress代理的并不是Pod的Service，而是Pod，之所以在配置的时候是配置的Service，是为了获取Pod的信息。


Ingress提供外部访问集群的入口，将外部的HTTP或者HTTPS请求转发到集群内Service上，流量规则是在Ingress资源上定义。
配置Ingress资源的必要条件是你的kubernetes集群种由Ingress controller。其中Ingress Controller常用的有如下：

• HAProxy Ingress Controller
• Nginx Ingress Controller
• Traefik Ingress Controller
• Kong Ingress Controller

其中最常用的是Nginx Controller和Traefik Ingress Controller。
定义一个简单的Ingresss:
[root@master ingress]# cat ingress-simple-daemo.yaml

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: ingress-simple-daemo
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - http:
      paths:
      - path: /joker
        backend:
          serviceName: nginx
          servicePort: 80

简要说明：
apiVersion，kind，metadata，spec都是Kubernetes YAML文件的标准字段，Ingress经常通过annotations来配置一些选项，比如rewrite-target，不同的Ingress Controller支持不同的annotations。对于规则而言，每个HTTP都有如下规则：

• 主机：主机是可选参数，如果不配置表示适用于所有主机HTTP通信，如果配置了表示只适用于该主机；
• 路径：类似于NG的location，每个路径后面都有后端ServiceName和ServicePort；
• 后端：后端是ServiceName和ServicePort组合，符合该规则的流量会转发到这个后端Service上。通常会在Ingress中配置默认后端，以匹配任何不符合规则的请求流量转发；
• 具体的语法规则可以通过kubectl explain ingress来查看。

1.1、Ingress 类型

1.1.1、单服务Ingress

Kubernetes中已经存在一些概念可以暴露单个service（查看替代方案），但是你仍然可以通过Ingress来实现，通过指定一个没有rule的默认backend的方式。比如：
[root@master ingress]# cat single-service-ingress.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: single-service-ingress
spec:
  backend:
    serviceName: nginx
    servicePort: 80

1.1.2、简单展开

如前面描述的那样，kubernete pod中的IP只在集群网络内部可见，我们需要在边界设置一个东西，让它能够接收ingress的流量并将它们转发到正确的端点上。这个东西一般是高可用的loadbalancer。使用Ingress能够允许你将loadbalancer的个数降低到最少，例如，假如你想要创建这样的一个设置：

foo.bar.com -> 178.91.123.132 -> / foo    service1:4200
                                 / bar    service2:8080

我们就可以这样配置Ingress：

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: simple-fanout-example
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: foo.bar.com
    http:
      paths:
      - path: /foo
        backend:
          serviceName: service1
          servicePort: 4200
      - path: /bar
        backend:
          serviceName: service2
          servicePort: 8080

1.1.3、基于名称的虚拟主机

如果想实现下面这种需求：

foo.bar.com --|                 |-> foo.bar.com s1:80
              | 178.91.123.132  |
bar.foo.com --|                 |-> bar.foo.com s2:80

我们就可以这样配置Ingress:

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: name-virtual-host-ingress
spec:
  rules:
  - host: foo.bar.com
    http:
      paths:
      - backend:
          serviceName: service1
          servicePort: 80
  - host: bar.foo.com
    http:
      paths:
      - backend:
          serviceName: service2
          servicePort: 80

如果要增加配置默认的backend，可以配置成如下Ingress：

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: name-virtual-host-ingress
spec:
  rules:
  - host: first.bar.com
    http:
      paths:
      - backend:
          serviceName: service1
          servicePort: 80
  - host: second.foo.com
    http:
      paths:
      - backend:
          serviceName: service2
          servicePort: 80
  - http:
      paths:
      - backend:
          serviceName: service3
          servicePort: 80

默认backend：一个没有rule的ingress，所有流量都将发送到一个默认backend。你可以用该技巧通知loadbalancer如何找到你网站的404页面，通过制定一些列rule和一个默认backend的方式。如果请求header中的host不能跟ingress中的host匹配，并且/或请求的URL不能与任何一个path匹配，则流量将路由到你的默认backend。

1.1.4、TLS

你可以通过指定包含TLS私钥和证书的secret来加密Ingress。 目前，Ingress仅支持单个TLS端口443，并假定TLS termination。 如果Ingress中的TLS配置部分指定了不同的主机，则它们将根据通过SNI TLS扩展指定的主机名（假如Ingress controller支持SNI）在多个相同端口上进行复用。 TLS secret中必须包含名为tls.crt和tls.key的密钥，这里面包含了用于TLS的证书和私钥，例如：

apiVersion: v1
kind: Secret
metadata:
  name: testsecret-tls
  namespace: default
data:
  tls.crt: base64 encoded cert
  tls.key: base64 encoded key
type: kubernetes.io/tls

在Ingress中引用这个secret将通知Ingress controller使用TLS加密从将客户端到loadbalancer的channel：

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: tls-example-ingress
spec:
  tls:
  - hosts:
    - sslexample.foo.com
    secretName: testsecret-tls
  rules:
    - host: sslexample.foo.com
      http:
        paths:
        - path: /
          backend:
            serviceName: service1
            servicePort: 80

注意：各种Ingress controller支持的TLS功能之间存在差距。 请参阅有关nginx，GCE或任何其他平台特定Ingress controller的文档，以了解TLS在你的环境中的工作原理。

1.2、Ingress更新

如果你想更改你现在正工作的Ingress，比如新增一个HOST，可以使用kubectl edit ingress my-ingress进行更新，在保存退出后其会触发Ingress Controller重新配置LB。比如我们现有一个ingress：

[root@master ingress]# kubectl get ingresses.
NAME                     HOSTS   ADDRESS   PORTS   AGE
      *                 80      58m

然后我们使用kubectl edit ingress ingress-simple-daemo来新增一个HOST：

......
spec:
  rules:
  - http:
      paths:
      - backend:
          serviceName: nginx-service
          servicePort: 8000
        path: /joker
  - host: bar.baz.com
    http:
      paths:
      - backend:
          serviceName: nginx
          servicePort: 80
        path: /foo
status:
  loadBalancer: {}

保存退出后就会生效：

[root@master ingress]# kubectl describe ingresses ingress-simple-daemo
Name:             ingress-simple-daemo
Namespace:        default
Address:          
Default backend:  default-http-backend:80 ()
Rules:
  Host         Path  Backends
  ----         ----  --------
  *            
               /joker   nginx-service:8000 (172.20.2.84:80)
  bar.baz.com  
               /foo   nginx:80 (172.20.2.79:80,172.20.2.82:80)
Annotations:
  kubernetes.io/ingress.class:                       traefik
  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"networking.k8s.io/v1beta1","kind":"Ingress","metadata":{"annotations":{"kubernetes.io/ingress.class":"traefik"},"name":"ingress-simple-daemo","namespace":"default"},"spec":{"rules":[{"http":{"paths":[{"backend":{"serviceName":"nginx-service","servicePort":8000},"path":"/joker"}]}}]}}

Events:  

二、Nginx Ingress

2.1、安装

2.1.1 在线安装

在线安装直接执行以下命令：

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/mandatory.yaml

然后安装NodePort：

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/provider/baremetal/service-nodeport.yaml

2.1.2、离线安装

到https://github.com/kubernetes/ingress-nginx/tree/master/deploy/static这个下面下载对应的YAML文件，有configmap.yaml，namespace.yaml，rbac.yaml，with-rbac.yaml，可以写一个如下循环下载：

for yaml in configmap.yaml namespace.yaml rbac.yaml with-rbac.yaml; do wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/$yaml;done

然后执行如下命令安装，前提先执行namespace.yaml这个YAML文件：

kubectl apply -f namespace.yaml
kubectl apply -f .

然后我们可以执行以下命令查看：

[root@master nginx]# kubectl get pod -n ingress-nginx
NAME                                        READY   STATUS              RESTARTS   AGE
nginx-ingress-controller-799dbf6fbd-zxvmp   0/1     ContainerCreating   0          12s

然后安装nodePort:

wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/provider/baremetal/service-nodeport.yaml
kubectl apply -f service-nodeport.yaml

然后我修改了nodePort的端口，如下：

apiVersion: v1
kind: Service
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: NodePort
  ports:
    - name: http
      port: 80
      targetPort: 80
      nodePort: 30080
      protocol: TCP
    - name: https
      port: 443
      targetPort: 443
      nodePort: 30443
      protocol: TCP
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---

然后查看结果：

[root@master nginx]# kubectl get pod -n ingress-nginx
NAME                                        READY   STATUS    RESTARTS   AGE
nginx-ingress-controller-799dbf6fbd-zxvmp   1/1     Running   0          52m
[root@master nginx]# kubectl get svc -n ingress-nginx
NAME            TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx   NodePort   10.68.194.177           80:30080/TCP,443:30443/TCP   46m

2.2、使用

先创建Pod，service，定义如下YAML：
[root@master test]# cat nginx-ingress-demo.yaml

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-deploy
  namespace: default
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx-demo
      release: canary
  template:
    metadata:
      name: my-nginx
      labels:
        app: nginx-demo
        release: canary
    spec:
      containers:
      - name: my-nginx
        image: nginx
        imagePullPolicy: IfNotPresent
        ports:
        - name: http
          containerPort: 80

---
apiVersion: v1
kind: Service
metadata:
  name: nginx-svc
  namespace: default
spec:
  selector:
    app: nginx-demo
    release: canary
  ports:
  - name: http
    port: 80
    targetPort: 80

然后执行kubectl apply -f nginx-ingress-demo.yaml，查看结果：

[root@master test]# kubectl get pod
NAME                            READY   STATUS    RESTARTS   AGE
nginx-deploy-549cb5c7ff-65fbb   1/1     Running   0          21s
nginx-deploy-549cb5c7ff-75fmt   1/1     Running   0          21s
nginx-deploy-549cb5c7ff-wg4w7   1/1     Running   0          17s
[root@master test]# kubectl get svc
NAME                     TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
kubernetes               ClusterIP   10.68.0.1              443/TCP          5d2h
nginx-svc                ClusterIP   10.68.214.28           80/TCP           6m21s

然后定义Ingress Nginx，YAML文件如下：
[root@master test]# cat ingress-nginx.yaml

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: ingress-nginx
  annotations:
    kubernetes.io/ingress.class: "nginx"
spec:
  rules:
  - host: 
    http:
      paths:
      - path:
        backend:
          serviceName: nginx-svc
          servicePort: 80

然后查看结果：

[root@master test]# kubectl describe ingresses ingress-nginx 
Name:             ingress-nginx
Namespace:        default
Address:          10.68.194.177
Default backend:  default-http-backend:80 ()
Rules:
  Host  Path  Backends
  ----  ----  --------
  *     
           nginx-svc:80 (172.20.1.61:80,172.20.1.62:80,172.20.2.87:80)
Annotations:
  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"networking.k8s.io/v1beta1","kind":"Ingress","metadata":{"annotations":{"kubernetes.io/ingress.class":"nginx"},"name":"ingress-nginx","namespace":"default"},"spec":{"rules":[{"host":null,"http":{"paths":[{"backend":{"serviceName":"nginx-svc","servicePort":80},"path":null}]}}]}}

  kubernetes.io/ingress.class:  nginx
Events:
  Type    Reason  Age                From                      Message
  ----    ------  ----               ----                      -------
  Normal  CREATE  11m                nginx-ingress-controller  Ingress default/ingress-nginx
  Normal  UPDATE  77s (x3 over 11m)  nginx-ingress-controller  Ingress default/ingress-nginx

在流量器访问：

2.3、TLS

Nginx Ingress不止支持HTTP，还支持HTTPS。我们使用如下命令手动创建证书：

openssl genrsa -out tls.key 2048
openssl req -new -x509  -key tls.key -out tls.crt -subj "/C=CN/ST=Chongqing/L=Chongqing/OU=DevOps/CN=nginx.joker.com"

然后配置Secrect：

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

然后查看：

[root@master test]# kubectl get secret
NAME                  TYPE                                  DATA   AGE
default-token-gmdbb   kubernetes.io/service-account-token   3      5d3h
tls-secret            kubernetes.io/tls                     2      20s
[root@master test]# kubectl describe secrets tls-secret
Name:         tls-secret
Namespace:    default
Labels:       
Annotations:  

Type:  kubernetes.io/tls

Data
====
tls.crt:  1302 bytes
tls.key:  1679 bytes

配置Ingress nginx:
[root@master test]# cat ingress-nginx-tls.yaml

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: ingress-nginx-tls
  annotations:
    kubernetes.io/ingress.class: "nginx"
spec:
  tls:
  - host:
    secretName: tls-secret
  rules:
  - host: 
    http:
      paths:
      - path:
        backend:
          serviceName: nginx-svc
          servicePort: 80

然后查看结果：

[root@master test]# kubectl get ingresses.
NAME                HOSTS   ADDRESS         PORTS     AGE
ingress-nginx-tls   *                       80, 443   4s

浏览器访问：

三、Traefik Ingress

3.1、安装

创建namespace（namespace.yaml）：

apiVersion: v1
kind: Namespace
metadata:
  name: ingress-traefik
  labels:
    app.kubernetes.io/name: ingress-traefik
    app.kubernetes.io/part-of: ingress-traefik
---

创建RBAC安全认证（rdac.yaml）：

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
  namespace: ingress-traefik 
---
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: ingress-traefik 

配置traefik（traefik.yaml）：

---
kind: Deployment
apiVersion: extensions/v1beta1
metadata:
  name: traefik-ingress-controller
  namespace: ingress-traefik 
  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
#      tolerations:
#      - operator: "Exists"
#      nodeSelector:
#        kubernetes.io/hostname: master
      containers:
      - image: traefik:v1.7.17
        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: ingress-traefik 
spec:
  selector:
    k8s-app: traefik-ingress-lb
  ports:
    - protocol: TCP
      port: 80
      name: web
      nodePort: 38000
    - protocol: TCP
      port: 8080
      nodePort: 38080
      name: admin
  type: NodePort

然后执行如下命令创建：

kubectl apply -f .

查看其结果：

[root@master traefik]# kubectl get svc -n ingress-traefik 
NAME                      TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)                       AGE
traefik-ingress-service   NodePort   10.68.173.196           80:38000/TCP,8080:38080/TCP   9m19s
[root@master traefik]# kubectl get pod -n ingress-traefik 
NAME                                          READY   STATUS    RESTARTS   AGE
traefik-ingress-controller-86769d5d99-fvf82   1/1     Running   0          7m10s

Traefik提供一个WEB UI工具，就是上面8080端口，可以通过其映射的NodePort端口在浏览器访问，如下：

3.2、使用

使用和上面nginx ingress一样，只是在annotations里配置的kubernetes.io/ingress.class: "traefik"。

3.3、配置

生成SSL证书：

openssl req -newkey rsa:2048 -nodes -keyout tls.key -x509 -days 365 -out tls.crt

创建Secret来存储证书：

# kubectl create secret generic traefik-cert --from-file=tls.crt --from-file=tls.key -n ingress-traefik 

配置traefik，让其支持https，配置文件如下：

defaultEntryPoints = ["http", "https"]

[entryPoints]
  [entryPoints.http]
  address = ":80"
    [entryPoints.http.redirect]
      entryPoint = "https"
  [entryPoints.https]
  address = ":443"
    [entryPoints.https.tls]
      [[entryPoints.https.tls.certificates]]
      CertFile = "/ssl/tls.crt"
      KeyFile = "/ssl/tls.key"

将上面的 traefik.toml 配置文件通过一个 ConfigMap 对象挂载到 traefik pod 中去。
创建configMap：

# kubectl create configmap traefik-conf --from-file=traefik.toml -n ingress-traefik

更改traefik的YAML文件：

---
kind: Deployment
apiVersion: extensions/v1beta1
metadata:
  name: traefik-ingress-controller
  namespace: ingress-traefik 
  labels:
    k8s-app: traefik-ingress-lb
spec:
  replicas: 1
  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
      terminationGracePeriodSeconds: 60
#      tolerations:
#      - operator: "Exists"
#      nodeSelector:
#        kubernetes.io/hostname: master
      containers:
      - image: traefik:v1.7.17
        name: traefik-ingress-lb
        volumeMounts:
        - name: ssl
          mountPath: "/ssl"
        - name: config
          mountPath: "/config"
        ports:
        - name: http
          containerPort: 80
        - name: https
          containerPort: 443
        - name: admin
          containerPort: 8080
        args:
        - --configfile=/config/traefik.toml
        - --api
        - --kubernetes
        - --logLevel=INFO
      volumes:
      - name: ssl
        secret:
          secretName: traefik-cert
      - name: config
        configMap:
          name: traefik-conf
---
kind: Service
apiVersion: v1
metadata:
  name: traefik-ingress-service
  namespace: ingress-traefik 
spec:
  selector:
    k8s-app: traefik-ingress-lb
  ports:
    - protocol: TCP
      port: 80
      name: web
      nodePort: 38000
    - protocol: TCP
      port: 8080
      nodePort: 38080
      name: admin
  type: NodePort

然后生成配置清单，并查看日志观察其是否生效；

# kubectl apply -f traefik.yaml
# kubectl logs traefik-ingress-controller-867f5668dd-7p7tv -n ingress-traefik 
time="2019-11-25T08:25:30Z" level=info msg="Using TOML configuration file /config/traefik.toml"
time="2019-11-25T08:25:30Z" level=info msg="No tls.defaultCertificate given for https: using the first item in tls.certificates as a fallback."
time="2019-11-25T08:25:30Z" level=info msg="Traefik version v1.7.17 built on 2019-09-23_06:22:08PM"
time="2019-11-25T08:25:30Z" level=info msg="\nStats collection is disabled.\nHelp us improve Traefik by turning this feature on :)\nMore details on: https://docs.traefik.io/v1.7/basics/#collected-data\n"
time="2019-11-25T08:25:30Z" level=info msg="Preparing server https &{Address::443 TLS:0xc0002b22d0 Redirect: Auth: WhitelistSourceRange:[] WhiteList: Compress:false ProxyProtocol: ForwardedHeaders:0xc00050a100} with readTimeout=0s writeTimeout=0s idleTimeout=3m0s"
time="2019-11-25T08:25:30Z" level=info msg="Preparing server traefik &{Address::8080 TLS: Redirect: Auth: WhitelistSourceRange:[] WhiteList: Compress:false ProxyProtocol: ForwardedHeaders:0xc00050a120} with readTimeout=0s writeTimeout=0s idleTimeout=3m0s"
time="2019-11-25T08:25:30Z" level=info msg="Starting server on :443"
time="2019-11-25T08:25:30Z" level=info msg="Preparing server http &{Address::80 TLS: Redirect:0xc000843fc0 Auth: WhitelistSourceRange:[] WhiteList: Compress:false ProxyProtocol: ForwardedHeaders:0xc00050a0e0} with readTimeout=0s writeTimeout=0s idleTimeout=3m0s"
time="2019-11-25T08:25:30Z" level=info msg="Starting server on :8080"
time="2019-11-25T08:25:30Z" level=info msg="Starting provider configuration.ProviderAggregator {}"
time="2019-11-25T08:25:30Z" level=info msg="Starting server on :80"
time="2019-11-25T08:25:30Z" level=info msg="Starting provider *kubernetes.Provider {\"Watch\":true,\"Filename\":\"\",\"Constraints\":[],\"Trace\":false,\"TemplateVersion\":0,\"DebugLogGeneratedTemplate\":false,\"Endpoint\":\"\",\"Token\":\"\",\"CertAuthFilePath\":\"\",\"DisablePassHostHeaders\":false,\"EnablePassTLSCert\":false,\"Namespaces\":null,\"LabelSelector\":\"\",\"IngressClass\":\"\",\"IngressEndpoint\":null,\"ThrottleDuration\":0}"
time="2019-11-25T08:25:30Z" level=info msg="ingress label selector is: \"\""
time="2019-11-25T08:25:30Z" level=info msg="Creating in-cluster Provider client"
time="2019-11-25T08:25:30Z" level=info msg="Server configuration reloaded on :443"
time="2019-11-25T08:25:30Z" level=info msg="Server configuration reloaded on :8080"
time="2019-11-25T08:25:30Z" level=info msg="Server configuration reloaded on :80"

3.4、Rewrite

测试demo：

apiVersion: v1
kind: Service
metadata:
  name: nginx-demo
spec:
  selector:
    app: nginx
  ports:
  - name: nginx
    port: 80
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        imagePullPolicy: IfNotPresent

正常访问的ingress如下：

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

但是如果我们把path改为如下：

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-ingress-demo
  annotations:
    kubernetes.io/ingress.class: "traefik"
spec:
  rules:
  - host:
    http:
      paths:
      - backend:
          serviceName: nginx-demo
          servicePort: 80
        path: /app

那么这时候访问就会报404.



这时候我们可以在配置里加上rewrite规则，如下：

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-ingress-demo
  annotations:
    kubernetes.io/ingress.class: "traefik"
    traefik.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host:
    http:
      paths:
      - backend:
          serviceName: nginx-demo
          servicePort: 80
        path: /app

然后就可以正常访问了，如下：



为了更友好化，我们可以定义如下：

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-ingress-demo
  annotations:
    kubernetes.io/ingress.class: "traefik"
    traefik.ingress.kubernetes.io/rewrite-target: /$2
spec:
  rules:
  - host:
    http:
      paths:
      - backend:
          serviceName: nginx-demo
          servicePort: 80
        path: /app(/|$)(.*)

但是这种还是会有问题，比如有的静态资源无法正常显示，比如静态资源的路径在/static下面，现在我们做了 url rewrite 过后，要正常访问也需要带上前缀才可以：http://xxx.xxx/static/screen.css，对于图片或者其他静态资源也是如此，当然我们去更改页面引入静态资源的方式为相对路径也是可以的，但是毕竟要修改代码，这个时候我们可以借助 ingress-traefik 中的 configuration-snippet 来对静态资源做一次跳转，如下所示： ```yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: nginx-ingress-demo annotations: kubernetes.io/ingress.class: "traefik" traefik.ingress.kubernetes.io/rewrite-target: /$2 traefik.ingress.kubernetes.io/configuration-snippet: | rewrite ^/static/(.*)$ /app/static/$1 redirect; rewrite ^/image/(.*)$ /app/image/$1 redirect; spec: rules: - host: http: paths: - backend: serviceName: nginx-demo servicePort: 80 path: /app(/|$)(.*) ```

这时候就可以正常加载静态资源了。


但是我们还想直接访问主域名，但是会报404，要解决这种问题，可以app-root的注解，这样我们访问主域名的时候就可以跳转到app-root目录（真实存在的路径）下面，如下：

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-ingress-demo
  annotations:
    kubernetes.io/ingress.class: "traefik"
    traefik.ingress.kubernetes.io/app-root: /app/
    traefik.ingress.kubernetes.io/rewrite-target: /$2
    traefik.ingress.kubernetes.io/configuration-snippet: |
      rewrite ^/static/(.*)$ /app/static/$1 redirect;
      rewrite ^/image/(.*)$ /app/image/$1 redirect;
spec:
  rules:
  - host:
    http:
      paths:
      - backend:
          serviceName: nginx-demo
          servicePort: 80
        path: /app(/|$)(.*)

但是还有一个问题是我们的 path 路径其实也匹配了 /app 这样的路径，可能我们更加希望我们的应用在最后添加一个 / 这样的 slash，同样我们可以通过 configuration-snippet 配置来完成，如下 Ingress 对象：

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-ingress-demo
  annotations:
    kubernetes.io/ingress.class: "traefik"
    traefik.ingress.kubernetes.io/app-root: /app/
    traefik.ingress.kubernetes.io/rewrite-target: /$2
    traefik.ingress.kubernetes.io/configuration-snippet: |
      rewrite ^(/app)$ $1/ redirect;
      rewrite ^/static/(.*)$ /app/static/$1 redirect;
      rewrite ^/image/(.*)$ /app/image/$1 redirect;
spec:
  rules:
  - host:
    http:
      paths:
      - backend:
          serviceName: nginx-demo
          servicePort: 80
        path: /app(/|$)(.*)