ingress

ingress 是什么?

node 节点的服务暴露通过service 的nodePort 可以实现端口的暴露。

但是通过nodePort这种方式暴露端口信息会有一些缺陷。

  • 每个端口只能使用一次，一个端口对应了一个应用
  • 实际访问中是使用域名访问，通过域名来访问到端口的服务中

而ingress就是为了弥补nodePort 访问的方式的不足的。

通过ingress可以定义规则来允许进入集群的请求被转发到集群中对应服务上，从来实现服务暴露。

ingress 和service 和pod的关系;

ingress 关联了一组service ，作为一个访问的入口，访问到service ，service 再访问到对应的pod

为什么用ingress 而不用nginx

ingress 可以实现通过域名访问service 进而访问到内部的pod。看起来好像跟nginx的功能类似。

虽然可以使用nginx实现类似的功能，但是如果有新加入的服务的话，需要去更新nginx pod 的配置信息。

而ingress 将nginx 和service 的关联通过Ingress Controller 和 Ingress 进行抽象出来，更加的方便管理。

ingress 重要概念

ingress

ingress 是 api的一个资源对象，通过yaml配置，可以定义请求如何转发到对应的service 上

ingress-controller

外部对集群的请求流量会先到ingress-controller，而ingress对象是用来告诉ingress-controller该如何转发请求。
ingress-controller 是一个实现了反向代理和负载均衡的程序，具体的如何反向代理请求的规则去对应的ingress 中进行获取，根据ingress 的定义的服务进行兴趣。
ingress-controller 有许多的实现，目前比较常用的有nginx-ingress 。当然也有一些其他的 ingress-controller

使用ingress实现自定义域名的访问

  1. 创建一个nginx 部署

//创建部署

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kubectl create deploy  nginx-deploy  --image=nginx  -n

//扩容4个

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kubectl scale  --replicas=5 deploy/nginx-deploy
  1. 创建服务，暴露服务的端口信息
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kubectl expose deploy nginx-deploy --port=80 --target-port=80   --type=NodePort

  1. 部署ingress controller

部署ingress-nginx

编辑部署文件

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vim ingress-controller.yaml

//进入粘贴模式，不然输入格式会乱
:set paste

i  输入模式

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

---

kind: ConfigMap
apiVersion: v1
metadata:
  name: nginx-configuration
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: tcp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: udp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nginx-ingress-serviceaccount
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: nginx-ingress-clusterrole
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - endpoints
      - nodes
      - pods
      - secrets
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - services
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - events
    verbs:
      - create
      - patch
  - apiGroups:
      - "extensions"
      - "networking.k8s.io"
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - "extensions"
      - "networking.k8s.io"
    resources:
      - ingresses/status
    verbs:
      - update

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
  name: nginx-ingress-role
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - pods
      - secrets
      - namespaces
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - configmaps
    resourceNames:
      # Defaults to "<election-id>-<ingress-class>"
      # Here: "<ingress-controller-leader>-<nginx>"
      # This has to be adapted if you change either parameter
      # when launching the nginx-ingress-controller.
      - "ingress-controller-leader-nginx"
    verbs:
      - get
      - update
  - apiGroups:
      - ""
    resources:
      - configmaps
    verbs:
      - create
  - apiGroups:
      - ""
    resources:
      - endpoints
    verbs:
      - get

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: nginx-ingress-role-nisa-binding
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: nginx-ingress-role
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: nginx-ingress-clusterrole-nisa-binding
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: nginx-ingress-clusterrole
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-ingress-controller
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: ingress-nginx
      app.kubernetes.io/part-of: ingress-nginx
  template:
    metadata:
      labels:
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx
      annotations:
        prometheus.io/port: "10254"
        prometheus.io/scrape: "true"
    spec:
      hostNetwork: true
      # wait up to five minutes for the drain of connections
      terminationGracePeriodSeconds: 300
      serviceAccountName: nginx-ingress-serviceaccount
      nodeSelector:
        kubernetes.io/os: linux
      containers:
        - name: nginx-ingress-controller
          image: rancher/nginx-ingress-controller:nginx-1.1.1-rancher1 
          imagePullPolicy: IfNotPresent
          args:
            - /nginx-ingress-controller
            - --configmap=$(POD_NAMESPACE)/nginx-configuration
            - --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
            - --udp-services-configmap=$(POD_NAMESPACE)/udp-services
            - --publish-service=$(POD_NAMESPACE)/ingress-nginx
            - --annotations-prefix=nginx.ingress.kubernetes.io
          securityContext:
            allowPrivilegeEscalation: true
            capabilities:
              drop:
                - ALL
              add:
                - NET_BIND_SERVICE
            # www-data -> 101
            runAsUser: 101
          env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          ports:
            - name: http
              containerPort: 80
              protocol: TCP
            - name: https
              containerPort: 443
              protocol: TCP
          livenessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 10
          readinessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 10
          lifecycle:
            preStop:
              exec:
                command:
                  - /wait-shutdown

---

apiVersion: v1
kind: LimitRange
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  limits:
  - min:
      memory: 90Mi
      cpu: 100m
    type: Container



应用文件

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kubectl apply -f ingress-controller.yaml

镜像比较大，如果阻塞可以手动拉取镜像 docker pull rancher/nginx-ingress-controller:nginx-1.1.1-rancher1

  1. 创建ingress 规则
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vim ingress.yaml

粘贴内容

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---
# http
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - host: ingress-test.com
    http:
      paths:
      - path: /
        backend:
          serviceName: nginx-deploy
          servicePort: 80

---
# https
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: tls-example-ingress
spec:
  tls:
  - hosts:
    - ssl-ingress-test.com
    secretName: secret-tls
  rules:
    - host: ssl-ingress-test.com
      http:
        paths:
        - path: /
          backend:
            serviceName: nginx-deploy
            servicePort: 80


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kubectl apply -f ingress.yaml

  1. 本机配置host域名映射信息
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192.168.1.102 ssl-ingress-test.com 
192.168.1.102 ingress-test.com

查看效果
http

https