一、Ingress介绍
Service对集群之外暴露服务的主要方式有两种： NotePort和LoadBalancer，但是这
两种方式，都有一定的缺点：
- NodePort方式的缺点是会占用很多集群机器的端口，那么当集群服务变多的时候，这个缺点就愈发明显
- LB方式的缺点是每个service需要一个外部LB设备，浪费、麻烦。并且需要kubernetes之外设备的支持
基于这种现状，
kubernetes提供了Ingress资源对象，Ingress只需要一个NodePort或者一个LB就可以满足暴露多个Service的需求。
工作机制如下图表示：
实际上，Ingress相当于一个7层的负载均衡器，是kubernetes对反向代理的一 个抽象，它的工作原理类似于Nginx，可以理解成
在Ingress里建立诸多映射规则，Ingress Controller通过监听这些配置规则并转化成Nginx的反向代理配置，然后对外部提供服务
。
在这里有两个核心概念：
-
ingress
：kubernetes中的一 个对象，作用是定义请求如何转发到service的规则 -
ingress controller
： 具体实现反向代理及负载均衡的程序,对ingress定义的规则进行解析,根据配置的规则来实现请求转发,实现方式有很多,比如Nginx, Contour, Haproxy等等
Ingress 的工作原理如下：
(以Nginx为例)
-
用户编写Ingress规则，说明哪个域名对应kubernetes集群中的哪个Service
-
Ingress控制器动态感知Ingress服务规则的变化， 然后生成一段对应的Nginx反向代理配置
-
Ingress控制器会将生成的Nginx配置写入到一个运行着的Nginx服务中,并动态更新
-
到此为止，其实真正在工作的就是一个Nginx了, 内部配置了用户定义的请求转发规则
二、Ingress使用
准备ingress环境
# 创建文件夹
[root@k8s-master ~]# mkdir ingress-controller
[root@k8s-master ~]# cd ingress-controller
# 获取ingress-nginx,本次案例使用的是0.30版本
[root@k8s-master ingress-controller]# wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.30.0/deploy/static/mandatory.yaml
[root@k8s-master ingress-controller]# wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.30.0/deploy/static/provider/baremetal/service-nodeport.yaml
[root@k8s-master ingress-controller]# ls
mandatory.yaml service-nodeport.yaml
# 创建ingress-nginx
[root@k8s-master ingress-controller]# kubectl apply -f .
namespace/ingress-nginx created
configmap/nginx-configuration created
configmap/tcp-services created
configmap/udp-services created
serviceaccount/nginx-ingress-serviceaccount created
clusterrole.rbac.authorization.k8s.io/nginx-ingress-clusterrole created
role.rbac.authorization.k8s.io/nginx-ingress-role created
rolebinding.rbac.authorization.k8s.io/nginx-ingress-role-nisa-binding created
clusterrolebinding.rbac.authorization.k8s.io/nginx-ingress-clusterrole-nisa-binding created
deployment.apps/nginx-ingress-controller created
limitrange/ingress-nginx created
service/ingress-nginx created
# 查看 ingress-nginx
[root@k8s-master ingress-controller]# kubectl get pod -n ingress-nginx -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-ingress-controller-7f74f657bd-cz5vx 1/1 Running 0 82s 10.244.2.129 k8s-node02 <none> <none>
# 如果一直拉取失败，那么修改 mandatory.yaml 文件中的仓库，将 image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.30.0 改为 image: quay-mirror.qiniu.com/kubernetes-ingress-controller/nginx-ingress-controller:0.30.0，然后重新apply
# 查看service
[root@k8s-master ingress-controller]# kubectl get svc -n ingress-nginx -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
ingress-nginx NodePort 10.104.194.71 <none> 80:32578/TCP,443:32553/TCP 3m14s app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx
准备service和pod
# 创建nginx-deployment，用于管理运行nginx的pod
# 创建tomcat-deployment，用于管理运行tomcat的pod
# 对nginx-deployment进行暴露
# 对tomcat-deployment进行暴露
[root@k8s-master ~]# vim nginx-tomcat.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
namespace: test
spec:
replicas: 3
selector:
matchLabels:
app: nginx-pod
template:
metadata:
labels:
app: nginx-pod
spec:
containers:
- name: nginx
image: nginx:1.17.1
ports:
- containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: tomcat-deployment
namespace: test
spec:
replicas: 3
selector:
matchLabels:
app: tomcat-pod
template:
metadata:
labels:
app: tomcat-pod
spec:
containers:
- name: tomcat
image: tomcat:8.5-jre10-slim
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
namespace: test
spec:
selector:
app: ngnx-pod
clusterIP: None
type: ClusterIP
ports:
- port: 80
targetPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: tomcat-service
namespace: test
spec:
selector:
app: tomcat-pod
clusterIP: None
type: ClusterIP
ports:
- port: 8080
targetPort: 8080
# 创建
[root@k8s-master ~]# kubectl create -f nginx-tomcat.yaml
deployment.apps/nginx-deployment created
deployment.apps/tomcat-deployment created
service/nginx-service created
service/tomcat-service created
# 查看
[root@k8s-master ~]# kubectl get svc,deploy,pod -n test -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/nginx-service ClusterIP None <none> 80/TCP 6s app=nginx-pod
service/tomcat-service ClusterIP None <none> 8080/TCP 6s app=tomcat-pod
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
deployment.apps/nginx-deployment 3/3 3 3 6s nginx nginx:1.17.1 app=nginx-pod
deployment.apps/tomcat-deployment 3/3 3 3 6s tomcat tomcat:8.5-jre10-slim app=tomcat-pod
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/nginx-deployment-6696798b78-kw8sk 1/1 Running 0 6s 10.244.1.164 k8s-node01 <none> <none>
pod/nginx-deployment-6696798b78-r9ffh 1/1 Running 0 6s 10.244.2.138 k8s-node02 <none> <none>
pod/nginx-deployment-6696798b78-wcj6p 1/1 Running 0 6s 10.244.1.163 k8s-node01 <none> <none>
pod/tomcat-deployment-58467d5474-gnfr8 1/1 Running 0 6s 10.244.2.137 k8s-node02 <none> <none>
pod/tomcat-deployment-58467d5474-hk84r 1/1 Running 0 6s 10.244.2.136 k8s-node02 <none> <none>
pod/tomcat-deployment-58467d5474-x5cc2 1/1 Running 0 6s 10.244.1.162 k8s-node01 <none> <none>
Http代理
# 编辑ingress资源清单文件
[root@k8s-master ~]# vim ingress-http.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-http
namespace: test
spec:
rules:
- host: nginx.test.com #域名
http:
paths:
- path: /
backend:
serviceName: nginx-service
servicePort: 80 # 当访问nginx.test.com/时，会将请求转发到名为nginx-service的Service的80端口上，然后Service在将请求转发到后端的pod中
- host: tomcat.test.com
http:
paths:
- path: /
backend:
serviceName: tomcat-service
servicePort: 8080
# 创建
[root@k8s-master ~]# kubectl create -f ingress-http.yaml
ingress.extensions/ingress-http created
# 查看
[root@k8s-master ~]# kubectl get ing ingress-http -n test
NAME HOSTS ADDRESS PORTS AGE
ingress-http nginx.test.com,tomcat.test.com 80 8s
[root@k8s-master ~]# kubectl describe ing ingress-http -n test
Name: ingress-http
Namespace: test
Address:
Default backend: default-http-backend:80 (<none>)
Rules:
Host Path Backends
---- ---- --------
nginx.test.com
/ nginx-service:80 (10.244.1.163:80,10.244.1.164:80,10.244.2.138:80)
tomcat.test.com
/ tomcat-service:8080 (10.244.1.162:8080,10.244.2.136:8080,10.244.2.137:8080)
Annotations:
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal CREATE 20s nginx-ingress-controller Ingress test/ingress-http
#接下来，在本地电脑上配置host文件，解析上面的两个域名到master主机上
C:\Windows\System32\drivers\etc\hosts
192.168.126.100 nginx.test.com
192.168.126.100 tomcat.test.com
查看服务对应的端口
[root@k8s-master ~]# kubectl get svc -n ingress-nginx -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
ingress-nginx NodePort 10.104.194.71 <none> 80:32578/TCP,443:32553/TCP 3h10m app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx
# http对外提供的端口为32578
测试
使用Ingress完成基于HTTP的反向代理功能就已实现
Https代理
# 创建证书
[root@k8s-master ~]# openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout tls.key -out tls.crt -subj "/C=CN/ST=BJ/L=BJ/0=nginx/CN=test.com"
Generating a 2048 bit RSA private key
.......................................................................+++
....................................................................................+++
writing new private key to 'tls.key'
-----
Subject Attribute 0 has no known NID, skipped
# 创建密钥
[root@k8s-master ~]# kubectl create secret tls tls-secret --key tls.key --cert tls.crt
secret/tls-secret created
# 创建nginx-deployment，用于管理运行nginx的pod
# 创建tomcat-deployment，用于管理运行tomcat的pod
# 对nginx-deployment进行暴露
# 对tomcat-deployment进行暴露
[root@k8s-master ~]# vim nginx-tomcat.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
namespace: test
spec:
replicas: 3
selector:
matchLabels:
app: nginx-pod
template:
metadata:
labels:
app: nginx-pod
spec:
containers:
- name: nginx
image: nginx:1.17.1
ports:
- containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: tomcat-deployment
namespace: test
spec:
replicas: 3
selector:
matchLabels:
app: tomcat-pod
template:
metadata:
labels:
app: tomcat-pod
spec:
containers:
- name: tomcat
image: tomcat:8.5-jre10-slim
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
namespace: test
spec:
selector:
app: ngnx-pod
clusterIP: None
type: ClusterIP
ports:
- port: 80
targetPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: tomcat-service
namespace: test
spec:
selector:
app: tomcat-pod
clusterIP: None
type: ClusterIP
ports:
- port: 8080
targetPort: 8080
# 创建
[root@k8s-master ~]# kubectl create -f nginx-tomcat.yaml
deployment.apps/nginx-deployment created
deployment.apps/tomcat-deployment created
service/nginx-service created
service/tomcat-service created
# 查看
[root@k8s-master ~]# kubectl get svc,deploy,pod -n test -o wide
[root@k8s-master ~]# kubectl get svc,deploy,pod -n test -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/nginx-service ClusterIP None <none> 80/TCP 7s app=nginx-pod
service/tomcat-service ClusterIP None <none> 8080/TCP 7s app=tomcat-pod
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
deployment.apps/nginx-deployment 3/3 3 3 7s nginx nginx:1.17.1 app=nginx-pod
deployment.apps/tomcat-deployment 3/3 3 3 7s tomcat tomcat:8.5-jre10-slim app=tomcat-pod
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/nginx-deployment-6696798b78-c2dfz 1/1 Running 0 7s 10.244.1.166 k8s-node01 <none> <none>
pod/nginx-deployment-6696798b78-ld5cp 1/1 Running 0 7s 10.244.1.165 k8s-node01 <none> <none>
pod/nginx-deployment-6696798b78-pfbfg 1/1 Running 0 7s 10.244.2.139 k8s-node02 <none> <none>
pod/tomcat-deployment-58467d5474-bs9r4 1/1 Running 0 7s 10.244.1.167 k8s-node01 <none> <none>
pod/tomcat-deployment-58467d5474-csxzc 1/1 Running 0 7s 10.244.2.140 k8s-node02 <none> <none>
pod/tomcat-deployment-58467d5474-fwm2n 1/1 Running 0 7s 10.244.2.141 k8s-node02 <none> <none>
# 编写基于https的ingress资源清单文件
[root@k8s-master ~]# vim ingress-https.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-https
namespace: test
spec:
tls:
- hosts:
- nginx.test.com
- tomcat.test.com
secretName: tls-secret #指定秘钥
rules:
- host: nginx.test.com
http:
paths:
- path: /
backend:
serviceName: nginx-service
servicePort: 80
- host: tomcat.test.com
http:
paths:
- path: /
backend:
serviceName: tomcat-service
servicePort: 8080
# 创建
[root@k8s-master ~]# kubectl create -f ingress-https.yaml
ingress.extensions/ingress-https created
# 查看
[root@k8s-master ~]# kubectl get ing -n test
NAME HOSTS ADDRESS PORTS AGE
ingress-https nginx.test.com,tomcat.test.com 80, 443 14s
[root@k8s-master ~]# kubectl describe ing ingress-https -n test
Name: ingress-https
Namespace: test
Address: 10.104.194.71
Default backend: default-http-backend:80 (<none>)
TLS:
tls-secret terminates nginx.test.com,tomcat.test.com
Rules:
Host Path Backends
---- ---- --------
nginx.test.com
/ nginx-service:80 (10.244.1.165:80,10.244.1.166:80,10.244.2.139:80)
tomcat.test.com
/ tomcat-service:8080 (10.244.1.167:8080,10.244.2.140:8080,10.244.2.141:8080)
Annotations:
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal CREATE 30s nginx-ingress-controller Ingress test/ingress-https
Normal UPDATE 14s nginx-ingress-controller Ingress test/ingress-https
#接下来，在本地电脑上配置host文件，解析上面的两个域名到master主机上
C:\Windows\System32\drivers\etc\hosts
192.168.126.100 nginx.test.com
192.168.126.100 tomcat.test.com
查看服务对应的端口
[root@k8s-master ~]# kubectl get svc -n ingress-nginx -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
ingress-nginx NodePort 10.104.194.71 <none> 80:32578/TCP,443:32553/TCP 3h28m app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx
# https对外提供的端口为32553
测试
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