ingress

概念

k8s的对外服务，ingress

service作用现在两个方面：

1、集群内部：不断跟踪的变化，更新endpoint中的pod对象，基于pod的ip地址不断变化的一种服务发现机制。

2、集群外部：类似于负载均衡器，把流量（ip+端口），不涉及转发url（http https），把请求转发到pod当中。

service：

NodePort: 容器端口-----service端口-----NodePort,设定了nodeport,每个节点都会有一个端口被打开30000-32767

ip+端口: 节点ip+30000-32767.s实现负载均衡

loadbalancer: 云平台上的一种service服务。云平台提供负载均衡ip地址

extrenal: 域名映射

ingress：

ingress基于城名进行映射，把url(http https)请求转发到service，再由service把请求转发到每一个pod.

ingress只要一个或者少量的狗官网ip或者LB，可以把多个http请求暴露到外网，七层反向代理。

service的service是一个基于域名和url路径，把一个或多个请求转发到service

ingress转发请求（七层）----service（四层）----pod

ingress的组成：

ingress是一个api对象，通过yaml文件来进行配置。ingress的作用是定义请求如何转发到service的规则，配置模板

ingress通过http和https暴露集群内部的service，给service提供一个外部的url，负载均衡，ssl/tls（https）的能力，实现一个基于域名的负载均衡。

ingress-controller：

具体的实现反向代理和负载均衡的程序。对ingress定义的规则进行解析，根据ingress的配置规则进行请求的转发。

ingress-controller：不是k8s自带的组件功能，ingress-controller一个统称。

nginx ingress controller，traefik都是ingress-controller，开源

ingress资源的定义项：

1、定义外部流量的路由规则

2、定义了服务暴露方式，主机名、url访问路径和其他属性

3、负载均衡（ingress-controller）

ingress-controller的运行方式是pod方式运行在集群当中

nginx-ingress-controller:

ingressbao露服务的方式：

1、方式一：deployment+LoadBalancer

deployment+LoadBalancer模式：ingress部署在公有云。会ingress里面会有一个type，type：LoadBalancer。公有云平台会为loadBalancer的service创建一个负载均衡器。绑定一个公网地址。

通过域名指向这个公网地址就可以实现集群对外暴露。

2、方式二：DaemonSet+hostnetwork+nodeSelector

DaemonSet：在每个节点都会创建一个pod

hostnetwork：pod共享节点主机的网络命令空间。容器内直接使用节点主机的ip+端口。pod直接访问主机上的的网络资源。

nodeSelector: 根据标签来选择部罢的节点。nginx-ingress-controller部罢的节点。

缺点：直接利用节点上的主机的网络和端口，一个node只能部署一个ingress-controller pod 比较适合大并发的生产环境，性能最好。

为什么适合大并发？？

pod共享节点主机的网络资源

客户端发起请求域名将先到DNS
DNS开始解析域名。映射到ingress-controller所在的节点
ingress-controller以pod形式运行在节点上。hostnetwork可以和节点主机共享网络
ingress的配置来定义URL的地址
根据ingress的标签匹配将请求转发到service
service寻找endpoints发现匹配能够转发的pod
最终还是由ingress-controller将请求转发到不同的pod上。实现负载均衡
service和endpoints在这里起发现和监控的总用
实际的负载均衡由ingress-controller实现

master01--
wget https://gitee.com/mirrors/ingress-nginx/raw/nginx-0.30.0/deploy/static/mandatory.yaml
修改mandatory.yaml
vim mandatory.yaml 
191 #kind: Deployment
192 kind: DaemonSet
200 #  replicas: 1
215       hostNetwork: true
220         test1: "true"
 
 
每台节点主机都添加nginx-ingress-controller镜像
tar -xf ingree.contro-0.30.0.tar.gz
docker load -i ingree.contro-0.30.0.tar
 
master01--
kubectal get pod -n ingress-nginx
 
kubectl label nodes node02 ingress=true
 
kubectl apply -f mandatory.yaml

在node02做映射

vim nginx.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: nfs-client-storageclass
  resources:
    requests:
      storage: 2Gi
 
---
#定义pod
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-app
  labels:
    app: nginx1
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx1
  template:
    metadata:
      labels:
        app: nginx1
    spec:
      containers:
        - name: nginx
          image: nginx:1.22
          volumeMounts:
          - name: nfs-pvc
            mountPath: /usr/share/nginx/html
      volumes:
      - name: nfs-pvc
        persistentVolumeClaim:
          claimName: nfs-pvc
 
---
#定义service
 
apiVersion: v1
kind: Service
metadata:
  name: nginx-app-svc
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  selector:
    app: nginx1
 
---
#定义ingress
 
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-app-ingress
spec:
  rules:
  - host: www.test1.com
    http:
      paths:
      - path: /
#匹配工作目录的根目录
        pathType: Prefix
#根据前缀进行匹配 只要是/开头的都可以匹配到例如/ www.test1.com/www1/www2/www3
        backend:
#指定后台服务器
          service:
            name: nginx-app-svc
            port:
              number: 80

查看挂载目录--192.168.10.40
echo 123 > index.html

访问
curl www.test2.com

3、方式三：demployment+nodePort

master01---
vim mandatory.yaml 
191 kind: Deployment
215       #hostNetwork: true
200   replicas: 1
219         kubernetes.io/os: linux
220         #test1: "true"
 
kubectl apply -f mandatory.yaml 
 
wget https://gitee.com/mirrors/ingress-nginx/raw/nginx-0.30.0/deploy/static/provider/baremetal/service-nodeport.yaml
#获取service-nodeport.yaml文件

mandatory.yaml 

service-nodeport.yaml

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
      protocol: TCP
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
#现在执行这个yaml文件，会生成一个service,在ingress-nginx这个命名空间生成一个service,所有的controller的请求都会
#从这个定义的service的nodeport的端口，把请求转发到自定义的service的pod

vim nodeport.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc2
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: nfs-client-storageclass
  resources:
    requests:
      storage: 2Gi
 
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-app2
  labels:
    app: nginx2
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx2
  template:
    metadata:
      labels:
        app: nginx2
    spec:
      containers:
        - name: nginx
          image: nginx:1.22
          volumeMounts:
          - name: nfs-pvc2
            mountPath: /usr/share/nginx/html
      volumes:
      - name: nfs-pvc2
        persistentVolumeClaim:
          claimName: nfs-pvc2
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-app-svc1
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  selector:
    app: nginx2
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-app-ingress
spec:
  rules:
  - host: www.test2.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: nginx-app-svc1
            port:
              number: 80
 
kubectl apply -f nodeport.yaml
 

查看挂载目录--192.168.10.40
echo lyw > index.html

在node02做映射

访问
curl www.test2.com:31679

nodeport不再是deployment的service创建的

核心的控制组件时nginx-ingress-controller

host----ingress的配置找到pod----controller----把请求发到pod

nodeport-----controller-----ingress----service----pod

nodeport暴露端口的方式是最简单的。nodeport多了一层net(地址转换)

并发量大的对性能会有一定影响。内部都会用nodeport
 

通过虚拟主机的方式实现http代理：

ingress的方式实现：一个ingress可以实现不同主机的访问

实验举例：

pod1.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment
  labels:
    test: nginx1
spec:
  replicas: 1
  selector:
    matchLabels:
      test: nginx1
  template:
    metadata:
      labels:
        test: nginx1
    spec:
      containers:
        - name: nginx1
          image: nginx:1.22
---
apiVersion: v1
kind: Service
metadata:
  name: svc-1
spec:
  ports:
    - port: 80
      targetPort: 80
      protocol: TCP
  selector:
    test: nginx1

pod2.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment2
  labels:
    test: nginx2
spec:
  replicas: 1
  selector:
    matchLabels:
      test: nginx2
  template:
    metadata:
      labels:
        test: nginx2
    spec:
      containers:
        - name: nginx1
          image: nginx:1.22
---      
apiVersion: v1
kind: Service 
metadata:
  name: svc-2 
spec:        
  ports:
    - port: 80
      targetPort: 80
      protocol: TCP
  selector: 
    test: nginx2

ingress1-2.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress1
spec:
  rules:
    - host: www.test1.com
      http:
        paths:
        - path: /
          pathType: Prefix
          backend:
            service:
              name: svc-1
              port:
                number: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress2
spec:
  rules:
    - host: www.test1.com
      http:
        paths:
        - path: /
          pathType: Prefix
          backend:
            service:
              name: svc-2
              port:
                number: 80

做映射

kubectl apply -f pod1.yaml
kubectl apply -f pod2.yaml
kubectl apply -f ingress1-2.yaml

curl www.test1.com:31679
curl www.test2.com:31679

daemonset+hostnetwork+nodeselector实现访问多个主机

实验举例：

nginx-service.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: nfs-client-storageclass
  resources:
    requests:
      storage: 2Gi

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-app
  labels:
    app: nginx1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx1
  template:
    metadata:
      labels:
        app: nginx1
    spec:
      containers:
        - name: nginx
          image: nginx:1.22
          volumeMounts:
          - name: nfs-pvc
            mountPath: /usr/share/nginx/html
      volumes:
      - name: nfs-pvc
        persistentVolumeClaim:
          claimName: nfs-pvc
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-app-svc
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  selector:
    app: nginx1
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-app-ingress
spec:
  rules:
  - host: www.test1.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: nginx-app-svc
            port:
              number: 80

nginx-service2.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc1
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: nfs-client-storageclass
  resources:
    requests:
      storage: 2Gi

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-app2
  labels:
    app: nginx2
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx2
  template:
    metadata:
      labels:
        app: nginx2
    spec:
      containers:
        - name: nginx
          image: nginx:1.22
          volumeMounts:
          - name: nfs-pvc1
            mountPath: /usr/share/nginx/html
      volumes:
      - name: nfs-pvc1
        persistentVolumeClaim:
          claimName: nfs-pvc1
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-app-svc2
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  selector:
    app: nginx2
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-app-ingress2
spec:
  rules:
  - host: www.test2.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: nginx-app-svc2
            port:
              number: 80

查看挂载目录--192.168.10.40
echo 123 > index.html
#连个pv都要写index.html

kubectl apply -f mandatory.yaml
kubectl apply -f nginx-service.yaml
kubectl apply -f nginx-service2.yaml

总结

ingress-controller两种方式：nginx-ingress-controller、traefik

ingress-controller的三种工作模式：

deployment+loadbalancer：需要云平台提供一个负载均衡的公网地址。公有云上做。需要收费

daemonset+hostnetwork+nodeselector：一般都会指定节点部署controller。缺点就是和宿主机共享网络，只能是一个controller的pod

hostnetwork会和宿主机共享网络。所以需要指定标签

deployment+NodePort：这是最常用最简单的方式。他会集中一个nodeport端口，所有ingress的请求都会转发到nodeport。然后由service将流量转发到pod

一个ingress的nodeport可以实现访问多个虚拟主机。和nginx类似。同一个端口下可以有多个域名