k8s---ingress对外服务（七层）
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.com3、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: nginx2ingress1-2.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:31679daemonset+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