Service详解【六】
发布时间：2023年12月23日
文章目录
6. Service详解
6.1 Service介绍
在kubernetes中，pod是应用程序的载体，我们可以通过pod的ip来访问应用程序，但是pod的ip地址不是固定的，这也就意味着不方便直接采用pod的ip对服务进行访问。
为了解决这个问题，kubernetes提供了Service资源，Service会对提供同一个服务的多个pod进行聚合，并且提供一个统一的入口地址。通过访问Service的入口地址就能访问到后面的pod服务。
Service在很多情况下只是一个概念，真正起作用的其实是kube-proxy服务进程，每个Node节点上都运行着一个kube-proxy服务进程。当创建Service的时候会通过api-server向etcd写入创建的service的信息，而kube-proxy会基于监听的机制发现这种Service的变动，然后它会将最新的Service信息转换成对应的访问规则。
# 10.98.132.219:80 是service提供的访问入口
# 当访问这个入口的时候，可以发现后面有三个pod的服务在等待调用，
# kube-proxy会基于rr（轮询）的策略，将请求分发到其中一个pod上去
# 这个规则会同时在集群内的所有节点上都生成，所以在任何一个节点上访问都可以。
[root@k8s-master ~]# ipvsadm -Ln
TCP 10.98.132.219:80 rr
-> 10.244.1.74:80 Masq 1 0 0
-> 10.244.1.75:80 Masq 1 0 0
-> 10.244.2.39:80 Masq 1 0 0
kube-proxy目前支持三种工作模式:
userspace 模式
userspace模式下，kube-proxy会为每一个Service创建一个监听端口，发向Cluster IP的请求被Iptables规则重定向到kube-proxy监听的端口上，kube-proxy根据LB算法选择一个提供服务的Pod并和其建立链接，以将请求转发到Pod上。 该模式下，kube-proxy充当了一个四层负责均衡器的角色。由于kube-proxy运行在userspace中，在进行转发处理时会增加内核和用户空间之间的数据拷贝，虽然比较稳定，但是效率比较低。
iptables 模式
iptables模式下，kube-proxy为service后端的每个Pod创建对应的iptables规则，直接将发向Cluster IP的请求重定向到一个Pod IP。 该模式下kube-proxy不承担四层负责均衡器的角色，只负责创建iptables规则。该模式的优点是较userspace模式效率更高，但不能提供灵活的LB策略，当后端Pod不可用时也无法进行重试。
ipvs 模式
ipvs模式和iptables类似，kube-proxy监控Pod的变化并创建相应的ipvs规则。ipvs相对iptables转发效率更高。除此以外，ipvs支持更多的LB算法。
# 此模式必须安装ipvs内核模块，否则会降级为iptables
# 开启ipvs
[root@k8s-master ~]# kubectl edit configmap kube-proxy -n kube-system # 修改mode: "ipvs"
configmap/kube-proxy edited
[root@k8s-master ~]# kubectl get pod -n kube-system -w | grep kube-proxy
kube-proxy-5khd8 1/1 Running 7 (23m ago) 6d17h
kube-proxy-slgjr 1/1 Running 7 (23m ago) 6d17h
kube-proxy-wbvk4 1/1 Running 7 (23m ago) 6d17h
[root@k8s-master ~]# kubectl get pod -n kube-system --show-labels | grep kube-proxy
kube-proxy-5khd8 1/1 Running 7 (26m ago) 6d17h controller-revision-hash=5794bbcc88,k8s-app=kube-proxy,pod-template-generation=1
kube-proxy-slgjr 1/1 Running 7 (27m ago) 6d17h controller-revision-hash=5794bbcc88,k8s-app=kube-proxy,pod-template-generation=1
kube-proxy-wbvk4 1/1 Running 7 (26m ago) 6d17h controller-revision-hash=5794bbcc88,k8s-app=kube-proxy,pod-template-generation=1
[root@k8s-master ~]#
# 删除kube-proxy 里的标签：k8s-app=kube-proxy
[root@k8s-master ~]# kubectl delete pod -l k8s-app=kube-proxy -n kube-system
pod "kube-proxy-5khd8" deleted
pod "kube-proxy-slgjr" deleted
pod "kube-proxy-wbvk4" deleted
[root@k8s-master ~]#
[root@k8s-master ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.96.0.1:443 rr
-> 10.10.10.148:6443 Masq 1 0 0
TCP 10.96.0.10:53 rr
-> 10.244.0.16:53 Masq 1 0 0
-> 10.244.0.17:53 Masq 1 0 0
TCP 10.96.0.10:9153 rr
-> 10.244.0.16:9153 Masq 1 0 0
-> 10.244.0.17:9153 Masq 1 0 0
TCP 10.106.59.48:443 rr
-> 10.244.2.93:4443 Masq 1 0 0
UDP 10.96.0.10:53 rr
-> 10.244.0.16:53 Masq 1 0 0
-> 10.244.0.17:53 Masq 1 0 0
[root@k8s-master ~]#
6.2 Service类型
Service的资源清单文件：
apiVersion: v1 # 资源版本
kind: Service # 资源类型
metadata: # 元数据
name: service-name # 资源名称
namespace: dev # 命名空间
spec: # 描述
selector: # 标签选择器，用于确定当前service代理哪些pod
app: nginx
type: # Service类型，指定service的访问方式
clusterIP: # 虚拟服务的ip地址
sessionAffinity: # session亲和性，支持ClientIP、None两个选项
ports: # 端口信息
- protocol: TCP
port: 3017 # service端口
targetPort: 5003 # pod端口
nodePort: 31122 # 主机端口
- ClusterIP：默认值，它是Kubernetes系统自动分配的虚拟IP，只能在集群内部访问
- NodePort：将Service通过指定的Node上的端口暴露给外部，通过此方法，就可以在集群外部访问服务
- LoadBalancer：使用外接负载均衡器完成到服务的负载分发，注意此模式需要外部云环境支持
- ExternalName： 把集群外部的服务引入集群内部，直接使用
6.3 Service使用
6.3.1 实验环境准备
在使用service之前，首先利用Deployment创建出3个pod，注意要为pod设置app=service-deployment的标签
创建deployment.yaml，内容如下：
apiVersion: apps/v1
kind: Deployment
metadata:
name: service-deployment
namespace: dev
spec:
replicas: 3
selector:
matchLabels:
app: service-deployment
template:
metadata:
labels:
app: service-deployment
spec:
containers:
- name: nginx-containers
image: nginx:1.20.0
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
protocol: "TCP"
[root@k8s-master deployment]# pwd
/root/inventory/deployment
[root@k8s-master deployment]#
[root@k8s-master deployment]# kubectl apply -f service-deployment.yaml
deployment.apps/service-deployment created
# 查看pod详情
[root@k8s-master deployment]# kubectl get pod -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
service-deployment-788d874977-tgqfn 1/1 Running 0 20s app=service-deployment,pod-template-hash=788d874977
service-deployment-788d874977-tpfkp 1/1 Running 0 20s app=service-deployment,pod-template-hash=788d874977
service-deployment-788d874977-wz48l 1/1 Running 0 20s app=service-deployment,pod-template-hash=788d874977
[root@k8s-master deployment]#
[root@k8s-master ~]# kubectl get pod -n dev -o wide
NAME READY STATUS RESTARTS AGE IP NODE ······
service-deployment-788d874977-tgqfn 1/1 Running 0 4m8s 10.244.2.94 k8s-node2 ······
service-deployment-788d874977-tpfkp 1/1 Running 0 4m8s 10.244.1.102 k8s-node1 ······
service-deployment-788d874977-wz48l 1/1 Running 0 4m8s 10.244.1.103 k8s-node1 ······
[root@k8s-master ~]#
# 为了方便后面的测试，修改下三台nginx的index.html页面（三台修改的IP地址不一致）
# kubectl exec -it service-deployment-788d874977-tgqfn -n dev /bin/sh
# echo "10.244.2.94" > /usr/share/nginx/html/index.html
[root@k8s-master ~]# kubectl exec service-deployment-788d874977-tgqfn -itn dev -- /bin/bash
root@service-deployment-788d874977-tgqfn:/# echo '10.244.2.94' > /usr/share/nginx/html/index.html
root@service-deployment-788d874977-tgqfn:/# exit
exit
# -c 指定容器名字 ; -it 交互模式 ; -n 指定名称空间
[root@k8s-master ~]# kubectl exec service-deployment-788d874977-tpfkp -c nginx-containers -itn dev -- /bin/bash
root@service-deployment-788d874977-tpfkp:/# echo '10.244.1.102' > /usr/share/nginx/html/index.html
root@service-deployment-788d874977-tpfkp:/# exit
exit
[root@k8s-master ~]# kubectl exec service-deployment-788d874977-wz48l -c nginx-containers -itn dev -- /bin/bash
root@service-deployment-788d874977-wz48l:/# echo '10.244.1.103' > /usr/share/nginx/html/index.html
root@service-deployment-788d874977-wz48l:/# exit
exit
[root@k8s-master ~]#
#修改完毕之后，访问测试
[root@k8s-master ~]# curl 10.244.2.94
10.244.2.94
[root@k8s-master ~]# curl 10.244.1.102
10.244.1.102
[root@k8s-master ~]# curl 10.244.1.103
10.244.1.103
[root@k8s-master ~]#
6.3.2 ClusterIP类型的Service
创建service-clusterip.yaml文件
apiVersion: v1
kind: Service
metadata:
name: service-cluster
namespace: dev
spec:
selector:
app: service-deployment
clusterIP: 10.98.132.219 # service的ip地址，如果不写，默认会生成一个
type: ClusterIP
ports:
- port: 80 # Service端口
targetPort: 80 # pod端口
# 创建service
[root@k8s-master service]# pwd
/root/inventory/service
[root@k8s-master service]# kubectl apply -f service-clusterip.yaml
service/service-cluster created
# 查看service
[root@k8s-master service]# kubectl get service -n dev -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service-cluster ClusterIP 10.98.132.219 <none> 80/TCP 12s app=service-deployment
# 查看service的详细信息
# 在这里有一个Endpoints列表，里面就是当前service可以负载到的服务入口
[root@k8s-master service]# kubectl describe service service-cluster -n dev
Name: service-cluster
Namespace: dev
Labels: <none>
Annotations: <none>
Selector: app=service-deployment
Type: ClusterIP
IP Family Policy: SingleStack
IP Families: IPv4
IP: 10.98.132.219
IPs: 10.98.132.219
Port: <unset> 80/TCP
TargetPort: 80/TCP
Endpoints: 10.244.1.102:80,10.244.1.103:80,10.244.2.94:80
Session Affinity: None
Events: <none>
[root@k8s-master service]#
# 查看ipvs的映射规则
[root@k8s-master ~]# ipvsadm -Ln
TCP 10.98.132.219:80 rr
-> 10.244.1.102:80 Masq 1 0 0
-> 10.244.1.103:80 Masq 1 0 0
-> 10.244.2.94:80 Masq 1 0 0
# 访问10.98.132.219:80观察效果。负载均衡
[root@k8s-master ~]# curl 10.98.132.219
10.244.2.94
[root@k8s-master ~]# curl 10.98.132.219
10.244.1.103
[root@k8s-master ~]# curl 10.98.132.219
10.244.1.102
[root@k8s-master ~]# curl 10.98.132.219
10.244.2.94
[root@k8s-master ~]# curl 10.98.132.219
10.244.1.103
[root@k8s-master ~]# curl 10.98.132.219
10.244.1.102
[root@k8s-master ~]# kubectl get endpoints -n dev
NAME ENDPOINTS AGE
service-cluster 10.244.1.102:80,10.244.1.103:80,10.244.2.94:80 9m16s
Endpoint
Endpoint是kubernetes中的一个资源对象，存储在etcd中，用来记录一个service对应的所有pod的访问地址，它是根据service配置文件中selector描述产生的。
一个Service由一组Pod组成，这些Pod通过Endpoints暴露出来，Endpoints是实现实际服务的端点集合。换句话说，service和pod之间的联系是通过endpoints实现的。
负载分发策略
对Service的访问被分发到了后端的Pod上去，目前kubernetes提供了两种负载分发策略：
-
如果不定义，默认使用kube-proxy的策略，比如随机、轮询
-
基于客户端地址的会话保持模式，即来自同一个客户端发起的所有请求都会转发到固定的一个Pod上，此模式可以使在spec中添加
sessionAffinity:ClientIP选项
# 查看ipvs的映射规则【rr 轮询】
[root@k8s-master ~]# ipvsadm -Ln
TCP 10.98.132.219:80 rr
-> 10.244.1.102:80 Masq 1 0 0
-> 10.244.1.103:80 Masq 1 0 0
-> 10.244.2.94:80 Masq 1 0 0
# 循环访问测试
[root@k8s-master ~]# while true;do curl 10.98.132.219:80; sleep 5; done
10.244.2.94
10.244.1.103
10.244.1.102
10.244.2.94
10.244.1.103
10.244.1.102
10.244.2.94
10.244.1.103
10.244.1.102
10.244.2.94
# 修改分发策略----sessionAffinity: ClientIP
# 查看ipvs规则【persistent 代表持久】
[root@k8s-master ~]# ipvsadm -Ln | grep -A 3 '10.98.132.219'
TCP 10.98.132.219:80 rr
-> 10.244.1.102:80 Masq 1 0 3
-> 10.244.1.103:80 Masq 1 0 3
-> 10.244.2.94:80 Masq 1 0 4
[root@k8s-master ~]#
[root@k8s-master ~]# cd inventory/service/
[root@k8s-master service]# vim service-clusterip.yaml
apiVersion: v1
kind: Service
metadata:
name: service-cluster
namespace: dev
spec:
sessionAffinity: ClientIP # 添加
clusterIP: 10.98.132.219
selector:
app: service-deployment
type: ClusterIP
ports:
- port: 80
targetPort: 80
[root@k8s-master service]# kubectl apply -f service-clusterip.yaml
service/service-cluster configured
[root@k8s-master service]#
# 循环访问测试
[root@k8s-master ~]# while true;do curl 10.98.132.219:80; sleep 5; done
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
10.244.1.103
root@k8s-master ~]# ipvsadm -Ln | grep -A 3 '10.98.132.219:80'
TCP 10.98.132.219:80 rr persistent 10800
-> 10.244.1.102:80 Masq 1 0 0
-> 10.244.1.103:80 Masq 1 0 12 # 表示访问12次
-> 10.244.2.94:80 Masq 1 0 0
[root@k8s-master ~]#
6.3.3 HeadLiness类型的Service
在某些场景中，开发人员可能不想使用Service提供的负载均衡功能，而希望自己来控制负载均衡策略，针对这种情况，kubernetes提供了HeadLiness Service，这类Service不会分配Cluster IP，如果想要访问service，只能通过service的域名进行查询。
创建service-headliness.yaml
apiVersion: v1
kind: Service
metadata:
name: service-headliness
namespace: dev
spec:
selector:
app: service-deployment
clusterIP: None # 将clusterIP设置为None，即可创建headliness Service
type: ClusterIP
ports:
- port: 80 # Service端口
targetPort: 80 # Pod 端口
# 创建 service
[root@k8s-master service]# pwd
/root/inventory/service
[root@k8s-master service]# kubectl apply -f service-headliness.yaml
service/service-headliness created
# 获取service， 发现CLUSTER-IP未分配
[root@k8s-master ~]# kubectl get service service-headliness -n dev -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service-headliness ClusterIP None <none> 80/TCP 35s app=service-deployment
# 查看service详情
[root@k8s-master ~]# kubectl describe service service-headliness -n dev
Name: service-headliness
Namespace: dev
Labels: <none>
Annotations: <none>
Selector: app=service-deployment
Type: ClusterIP
IP Family Policy: SingleStack
IP Families: IPv4
IP: None
IPs: None
Port: <unset> 80/TCP
TargetPort: 80/TCP
Endpoints: 10.244.1.102:80,10.244.1.103:80,10.244.2.94:80
Session Affinity: None
Events: <none>
[root@k8s-master ~]# kubectl get pod -n dev
NAME READY STATUS RESTARTS AGE
service-deployment-788d874977-tgqfn 1/1 Running 0 58m
service-deployment-788d874977-tpfkp 1/1 Running 0 58m
service-deployment-788d874977-wz48l 1/1 Running 0 58m
# 查看域名的解析情况
[root@k8s-master ~]# kubectl exec service-deployment-788d874977-tgqfn -itn dev -- /bin/bash
root@service-deployment-788d874977-tgqfn:/# cat /etc/resolv.conf
search dev.svc.cluster.local svc.cluster.local cluster.local
nameserver 10.96.0.10
options ndots:5
# 需要安装dig命令,安装yum install -y bind-utils ; 查找dig命令由那个包提供 yum provides dig
[root@k8s-master ~]# dig @10.96.0.10 service-headliness.dev.svc.cluster.local
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.15 <<>> @10.96.0.10 service-headliness.dev.svc.cluster.local
; (1 server found)
;; global options: +cmd
;; Got answer:
;; WARNING: .local is reserved for Multicast DNS
;; You are currently testing what happens when an mDNS query is leaked to DNS
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1422
;; flags: qr aa rd; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;service-headliness.dev.svc.cluster.local. IN A
;; ANSWER SECTION:
service-headliness.dev.svc.cluster.local. 30 IN A 10.244.1.102
service-headliness.dev.svc.cluster.local. 30 IN A 10.244.1.103
service-headliness.dev.svc.cluster.local. 30 IN A 10.244.2.94
;; Query time: 10 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Mon Dec 18 15:59:23 CST 2023
;; MSG SIZE rcvd: 237
[root@k8s-master ~]#
# 测试域名负载均衡
[root@k8s-master ~]# kubectl run nginx1 --image=nginx:1.20.0 -n dev
pod/nginx1 created
[root@k8s-master ~]# kubectl exec nginx1 -n dev -it -- /bin/bash
root@nginx1:/# curl service-headliness.dev.svc.cluster.local
10.244.1.103
root@nginx1:/# curl service-headliness.dev.svc.cluster.local
10.244.1.102
root@nginx1:/# curl service-headliness.dev.svc.cluster.local
10.244.1.103
root@nginx1:/# curl service-headliness.dev.svc.cluster.local
10.244.1.102
root@nginx1:/# curl service-headliness.dev.svc.cluster.local
10.244.1.102
root@nginx1:/# curl service-headliness.dev.svc.cluster.local
10.244.1.103
root@nginx1:/# curl service-headliness.dev.svc.cluster.local
10.244.1.103
root@nginx1:/#
# 访问不到10.244.2.94是因为 k8s-node2
[root@k8s-master ~]# kubectl get pod -n dev -o wide
NAME READY STATUS RESTARTS AGE IP NODE ······
nginx1 1/1 Running 0 96s 10.244.1.110 k8s-node1 ······
service-deployment-788d874977-tgqfn 1/1 Running 0 85m 10.244.2.94 k8s-node2 ······
service-deployment-788d874977-tpfkp 1/1 Running 0 85m 10.244.1.102 k8s-node1 ······
service-deployment-788d874977-wz48l 1/1 Running 0 85m 10.244.1.103 k8s-node1 ······
[root@k8s-master ~]#
6.3.4 NodePort类型的Service
在之前的样例中，创建的Service的ip地址只有集群内部才可以访问，如果希望将Service暴露给集群外部使用，那么就要使用到另外一种类型的Service，称为NodePort类型。NodePort的工作原理其实就是将service的端口映射到Node的一个端口上，然后就可以通过NodeIp:NodePort来访问service了。
创建service-nodeport.yaml
apiVersion: v1
kind: Service
metadata:
name: service-nodeport
namespace: dev
spec:
clusterIP: 10.108.220.52 # service的ip地址，如果不写，默认会生成一个
selector:
app: service-deployment
type: NodePort # service类型
ports:
- port: 80
nodePort: 30002 # 指定绑定的node的端口(默认的取值范围是：30000-32767), 如果不指定，会默认分配
targetPort: 80
# 创建service
[root@k8s-master service]# pwd
/root/inventory/service
[root@k8s-master service]# kubectl apply -f service-nodeport.yaml
service/service-nodeport created
[root@k8s-master service]#
# 查看service
[root@k8s-master ~]# kubectl get service service-nodeport -n dev -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service-nodeport NodePort 10.108.220.52 <none> 80:30002/TCP 50s app=service-deployment
# 接下来可以通过电脑主机的浏览器去访问集群中任意一个nodeip的30002端口，即可访问到pod
# 打开cmd
C:\Users\agan9>curl 10.10.10.148:30002
10.244.2.94
C:\Users\agan9>curl 10.10.10.148:30002
10.244.1.103
C:\Users\agan9>curl 10.10.10.148:30002
10.244.1.102
C:\Users\agan9>curl 10.10.10.148:30002
10.244.2.94
C:\Users\agan9>curl 10.10.10.148:30002
10.244.1.103
C:\Users\agan9>curl 10.10.10.148:30002
10.244.1.102
6.3.5 LoadBalancer类型的Service
LoadBalancer和NodePort很相似，目的都是向外部暴露一个端口，区别在于LoadBalancer会在集群的外部再来做一个负载均衡设备，而这个设备需要外部环境支持的，外部服务发送到这个设备上的请求，会被设备负载之后转发到集群中。
6.3.6 ExternalName类型的Service
ExternalName类型的Service用于引入集群外部的服务，它通过externalName属性指定外部一个服务的地址，然后在集群内部访问此service就可以访问到外部的服务了。
apiVersion: v1
kind: Service
metadata:
name: service-externalname
namespace: dev
spec:
type: ExternalName # service类型
externalName: www.baidu.com #改成ip地址也可以
# 创建service
[root@k8s-master service]# pwd
/root/inventory/service
[root@k8s-master service]# kubectl apply -f service-externalname.yaml
service/service-externalname created
[root@k8s-master ~]# kubectl get service service-externalname -n dev
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service-externalname ExternalName <none> www.baidu.com <none> 15s
[root@k8s-master ~]#
# 域名解析
[root@k8s-master ~]# dig @10.96.0.10 service-externalname.dev.svc.cluster.local
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.15 <<>> @10.96.0.10 service-externalname.dev.svc.cluster.local
; (1 server found)
;; global options: +cmd
;; Got answer:
;; WARNING: .local is reserved for Multicast DNS
;; You are currently testing what happens when an mDNS query is leaked to DNS
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11466
;; flags: qr aa rd; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;service-externalname.dev.svc.cluster.local. IN A
;; ANSWER SECTION:
service-externalname.dev.svc.cluster.local. 30 IN CNAME www.baidu.com.
www.baidu.com. 30 IN A 36.155.132.76
www.baidu.com. 30 IN A 36.155.132.3
;; Query time: 26 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Mon Dec 18 21:17:40 CST 2023
;; MSG SIZE rcvd: 198
[root@k8s-master ~]#
6.4 Ingress介绍
在前面课程中已经提到，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LB，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。工作机制大致如下图表示：
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（以Nginx为例）的工作原理如下：
- 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
6.5 Ingress使用
6.5.1 环境准备
搭建ingress环境
官方的 deploy.yaml , 如果官方的镜像拉去不下来，就去docker官网找，在下面有写
apiVersion: v1
kind: Namespace
metadata:
labels:
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
name: ingress-nginx
---
apiVersion: v1
automountServiceAccountToken: true
kind: ServiceAccount
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx
namespace: ingress-nginx
---
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx
namespace: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- namespaces
verbs:
- get
- apiGroups:
- ""
resources:
- configmaps
- pods
- secrets
- endpoints
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- services
verbs:
- get
- list
- watch
- apiGroups:
- networking.k8s.io
resources:
- ingresses
verbs:
- get
- list
- watch
- apiGroups:
- networking.k8s.io
resources:
- ingresses/status
verbs:
- update
- apiGroups:
- networking.k8s.io
resources:
- ingressclasses
verbs:
- get
- list
- watch
- apiGroups:
- coordination.k8s.io
resourceNames:
- ingress-nginx-leader
resources:
- leases
verbs:
- get
- update
- apiGroups:
- coordination.k8s.io
resources:
- leases
verbs:
- create
- apiGroups:
- ""
resources:
- events
verbs:
- create
- patch
- apiGroups:
- discovery.k8s.io
resources:
- endpointslices
verbs:
- list
- watch
- get
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission
namespace: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- secrets
verbs:
- get
- create
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- configmaps
- endpoints
- nodes
- pods
- secrets
- namespaces
verbs:
- list
- watch
- apiGroups:
- coordination.k8s.io
resources:
- leases
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes
verbs:
- get
- apiGroups:
- ""
resources:
- services
verbs:
- get
- list
- watch
- apiGroups:
- networking.k8s.io
resources:
- ingresses
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- events
verbs:
- create
- patch
- apiGroups:
- networking.k8s.io
resources:
- ingresses/status
verbs:
- update
- apiGroups:
- networking.k8s.io
resources:
- ingressclasses
verbs:
- get
- list
- watch
- apiGroups:
- discovery.k8s.io
resources:
- endpointslices
verbs:
- list
- watch
- get
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission
rules:
- apiGroups:
- admissionregistration.k8s.io
resources:
- validatingwebhookconfigurations
verbs:
- get
- update
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx
namespace: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: ingress-nginx
subjects:
- kind: ServiceAccount
name: ingress-nginx
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission
namespace: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: ingress-nginx-admission
subjects:
- kind: ServiceAccount
name: ingress-nginx-admission
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: ingress-nginx
subjects:
- kind: ServiceAccount
name: ingress-nginx
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: ingress-nginx-admission
subjects:
- kind: ServiceAccount
name: ingress-nginx-admission
namespace: ingress-nginx
---
apiVersion: v1
data:
allow-snippet-annotations: "false"
kind: ConfigMap
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-controller
namespace: ingress-nginx
---
apiVersion: v1
kind: Service
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-controller
namespace: ingress-nginx
spec:
ipFamilies:
- IPv4
ipFamilyPolicy: SingleStack
ports:
- appProtocol: http
name: http
port: 80
protocol: TCP
targetPort: http
- appProtocol: https
name: https
port: 443
protocol: TCP
targetPort: https
selector:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
type: NodePort
---
apiVersion: v1
kind: Service
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-controller-admission
namespace: ingress-nginx
spec:
ports:
- appProtocol: https
name: https-webhook
port: 443
targetPort: webhook
selector:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
type: ClusterIP
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-controller
namespace: ingress-nginx
spec:
minReadySeconds: 0
revisionHistoryLimit: 10
selector:
matchLabels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
strategy:
rollingUpdate:
maxUnavailable: 1
type: RollingUpdate
template:
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
spec:
containers:
- args:
- /nginx-ingress-controller
- --election-id=ingress-nginx-leader
- --controller-class=k8s.io/ingress-nginx
- --ingress-class=nginx
- --configmap=$(POD_NAMESPACE)/ingress-nginx-controller
- --validating-webhook=:8443
- --validating-webhook-certificate=/usr/local/certificates/cert
- --validating-webhook-key=/usr/local/certificates/key
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: LD_PRELOAD
value: /usr/local/lib/libmimalloc.so
image: registry.k8s.io/ingress-nginx/controller:v1.9.4@sha256:5b161f051d017e55d358435f295f5e9a297e66158f136321d9b04520ec6c48a3
imagePullPolicy: IfNotPresent
lifecycle:
preStop:
exec:
command:
- /wait-shutdown
livenessProbe:
failureThreshold: 5
httpGet:
path: /healthz
port: 10254
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
name: controller
ports:
- containerPort: 80
name: http
protocol: TCP
- containerPort: 443
name: https
protocol: TCP
- containerPort: 8443
name: webhook
protocol: TCP
readinessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
resources:
requests:
cpu: 100m
memory: 90Mi
securityContext:
allowPrivilegeEscalation: true
capabilities:
add:
- NET_BIND_SERVICE
drop:
- ALL
runAsUser: 101
volumeMounts:
- mountPath: /usr/local/certificates/
name: webhook-cert
readOnly: true
dnsPolicy: ClusterFirst
nodeSelector:
kubernetes.io/os: linux
serviceAccountName: ingress-nginx
terminationGracePeriodSeconds: 300
volumes:
- name: webhook-cert
secret:
secretName: ingress-nginx-admission
---
apiVersion: batch/v1
kind: Job
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission-create
namespace: ingress-nginx
spec:
template:
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission-create
spec:
containers:
- args:
- create
- --host=ingress-nginx-controller-admission,ingress-nginx-controller-admission.$(POD_NAMESPACE).svc
- --namespace=$(POD_NAMESPACE)
- --secret-name=ingress-nginx-admission
env:
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
image: registry.k8s.io/ingress-nginx/kube-webhook-certgen:v20231011-8b53cabe0@sha256:a7943503b45d552785aa3b5e457f169a5661fb94d82b8a3373bcd9ebaf9aac80
imagePullPolicy: IfNotPresent
name: create
securityContext:
allowPrivilegeEscalation: false
nodeSelector:
kubernetes.io/os: linux
restartPolicy: OnFailure
securityContext:
fsGroup: 2000
runAsNonRoot: true
runAsUser: 2000
serviceAccountName: ingress-nginx-admission
---
apiVersion: batch/v1
kind: Job
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission-patch
namespace: ingress-nginx
spec:
template:
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission-patch
spec:
containers:
- args:
- patch
- --webhook-name=ingress-nginx-admission
- --namespace=$(POD_NAMESPACE)
- --patch-mutating=false
- --secret-name=ingress-nginx-admission
- --patch-failure-policy=Fail
env:
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
image: registry.k8s.io/ingress-nginx/kube-webhook-certgen:v20231011-8b53cabe0@sha256:a7943503b45d552785aa3b5e457f169a5661fb94d82b8a3373bcd9ebaf9aac80
imagePullPolicy: IfNotPresent
name: patch
securityContext:
allowPrivilegeEscalation: false
nodeSelector:
kubernetes.io/os: linux
restartPolicy: OnFailure
securityContext:
fsGroup: 2000
runAsNonRoot: true
runAsUser: 2000
serviceAccountName: ingress-nginx-admission
---
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: nginx
spec:
controller: k8s.io/ingress-nginx
---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission
namespace: ingress-nginx
spec:
egress:
- {}
podSelector:
matchLabels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
policyTypes:
- Ingress
- Egress
---
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingWebhookConfiguration
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.9.4
name: ingress-nginx-admission
webhooks:
- admissionReviewVersions:
- v1
clientConfig:
service:
name: ingress-nginx-controller-admission
namespace: ingress-nginx
path: /networking/v1/ingresses
failurePolicy: Fail
matchPolicy: Equivalent
name: validate.nginx.ingress.kubernetes.io
rules:
- apiGroups:
- networking.k8s.io
apiVersions:
- v1
operations:
- CREATE
- UPDATE
resources:
- ingresses
sideEffects: None
# 如果deploy.yaml中的镜像拉取不下来，查找可用的ingress-nginx-controller和kube-webhook-certgen镜像
# 手动拉取镜像需要在每个节点都要执行
[root@k8s-master ~]# docker pull dyrnq/ingress-nginx-controller:v1.9.0
v1.9.0: Pulling from dyrnq/ingress-nginx-controller
8a49fdb3b6a5: Pull complete
f55717a5fb17: Pull complete
2ccd9f72f01a: Pull complete
91f8bbc316f7: Pull complete
5956894d6526: Pull complete
4f4fb700ef54: Pull complete
f77fee091fe7: Pull complete
edb2563b3cf8: Pull complete
473620f35c96: Pull complete
1d5949a6578d: Pull complete
68162cf2f96d: Pull complete
dae023f980cd: Pull complete
df9e521b91a5: Pull complete
46fb48d2574a: Pull complete
Digest: sha256:c15d1a617858d90fb8f8a2dd60b0676f2bb85c54e3ed11511794b86ec30c8c60
Status: Downloaded newer image for dyrnq/ingress-nginx-controller:v1.9.0
[root@k8s-master ~]# docker pull dyrnq/kube-webhook-certgen:v20230407
v20230407: Pulling from dyrnq/kube-webhook-certgen
10f855b03c8a: Pull complete
fe5ca62666f0: Pull complete
fff4e558ad3a: Pull complete
fcb6f6d2c998: Pull complete
e8c73c638ae9: Pull complete
1e3d9b7d1452: Pull complete
4aa0ea1413d3: Pull complete
7c881f9ab25e: Pull complete
5627a970d25e: Pull complete
baeaa1a3b0bf: Pull complete
Digest: sha256:543c40fd093964bc9ab509d3e791f9989963021f1e9e4c9c7b6700b02bfb227b
Status: Downloaded newer image for dyrnq/kube-webhook-certgen:v20230407
docker.io/dyrnq/kube-webhook-certgen:v20230407
# 查看本地镜像
[root@k8s-master ~]# docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
dyrnq/ingress-nginx-controller v1.9.0 b559857d08cc 3 months ago 292MB
dyrnq/kube-webhook-certgen v20230407 7e7451bb7042 8 months ago 47.2MB
[root@k8s-master ~]#
# 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1.9.4版本
[root@k8s-master ingress-controller]# wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.9.4/deploy/static/provider/baremetal/deploy.yaml
[root@k8s-master ingress-controller]#
# 修改deploy.yaml
# 把官方镜像修改成 dyrnq/ingress-nginx-controller:v1.9.0 ; dyrnq/kube-webhook-certgen:v20230407
[root@k8s-master ingress-controller]# grep image deploy.yaml
image: registry.k8s.io/ingress-nginx/controller:v1.9.4@sha256:5b161f051d017e55d358435f295f5e9a297e66158f136321d9b04520ec6c48a3
imagePullPolicy: IfNotPresent
image: registry.k8s.io/ingress-nginx/kube-webhook-certgen:v20231011-8b53cabe0@sha256:a7943503b45d552785aa3b5e457f169a5661fb94d82b8a3373bcd9ebaf9aac80
imagePullPolicy: IfNotPresent
image: registry.k8s.io/ingress-nginx/kube-webhook-certgen:v20231011-8b53cabe0@sha256:a7943503b45d552785aa3b5e457f169a5661fb94d82b8a3373bcd9ebaf9aac80
imagePullPolicy: IfNotPresent
# 修改后的内容
[root@k8s-master ~]# grep image inventory/ingress-controller/deploy.yaml
image: dyrnq/ingress-nginx-controller:v1.9.0
imagePullPolicy: IfNotPresent
image: dyrnq/kube-webhook-certgen:v20230407
imagePullPolicy: IfNotPresent
image: dyrnq/kube-webhook-certgen:v20230407
imagePullPolicy: IfNotPresent
[root@k8s-master ~]#
# 创建ingress-nginx
[root@k8s-master ingress-controller]# kubectl apply -f deploy.yaml
namespace/ingress-nginx created
serviceaccount/ingress-nginx created
serviceaccount/ingress-nginx-admission created
role.rbac.authorization.k8s.io/ingress-nginx created
role.rbac.authorization.k8s.io/ingress-nginx-admission created
clusterrole.rbac.authorization.k8s.io/ingress-nginx created
clusterrole.rbac.authorization.k8s.io/ingress-nginx-admission created
rolebinding.rbac.authorization.k8s.io/ingress-nginx created
rolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
configmap/ingress-nginx-controller created
service/ingress-nginx-controller created
service/ingress-nginx-controller-admission created
deployment.apps/ingress-nginx-controller created
job.batch/ingress-nginx-admission-create created
job.batch/ingress-nginx-admission-patch created
ingressclass.networking.k8s.io/nginx created
networkpolicy.networking.k8s.io/ingress-nginx-admission created
validatingwebhookconfiguration.admissionregistration.k8s.io/ingress-nginx-admission created
[root@k8s-master ingress-controller]#
# 查看ingress-nginx的pod
[root@k8s-master ~]# kubectl get pod -n ingress-nginx
NAME READY STATUS RESTARTS AGE
ingress-nginx-admission-create-mpws6 0/1 Completed 0 11m
ingress-nginx-admission-patch-vlc9n 0/1 Completed 0 11m
ingress-nginx-controller-6d468f9b88-d784c 1/1 Running 0 11m
[root@k8s-master ~]#
# 查看service
[root@k8s-master ~]# kubectl get service -n ingress-nginx
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
ingress-nginx-controller NodePort 10.104.147.163 <none> 80:30433/TCP,443:31612/TCP 5m23s
ingress-nginx-controller-admission ClusterIP 10.102.191.232 <none> 443/TCP 5m23s
[root@k8s-master ~]#
准备service和pod
为了后面的实验比较方便，创建如下图所示的模型
创建tomcat-nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
namespace: dev
spec:
replicas: 3
selector:
matchLabels:
app: nginx-pod
template:
metadata:
labels:
app: nginx-pod
spec:
containers:
- name: nginx
image: nginx:1.20.0
ports:
- containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: tomcat-deployment
namespace: dev
spec:
replicas: 3
selector:
matchLabels:
app: tomcat-pod
template:
metadata:
labels:
app: tomcat-pod
spec:
containers:
- name: tomcat
image: tomcat:8.0-alpine
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
namespace: dev
spec:
selector:
app: nginx-pod
clusterIP: None
type: ClusterIP
ports:
- port: 80
targetPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: tomcat-service
namespace: dev
spec:
selector:
app: tomcat-pod
clusterIP: None
type: ClusterIP
ports:
- port: 8080
targetPort: 8080
# 创建
[root@k8s-master ~]# cd inventory/ingress-controller/
[root@k8s-master ingress-controller]# kubectl apply -f tomcat-nginx.yaml
deployment.apps/nginx-deployment created
deployment.apps/tomcat-deployment created
service/nginx-service created
service/tomcat-service created
[root@k8s-master ingress-controller]#
# 查看Pod
[root@k8s-master ~]# kubectl get pod -n dev
NAME READY STATUS RESTARTS AGE
nginx-deployment-7cb69f4885-f92jr 1/1 Running 0 69s
nginx-deployment-7cb69f4885-s645w 1/1 Running 0 69s
nginx-deployment-7cb69f4885-zjq8z 1/1 Running 0 69s
tomcat-deployment-79cd69847d-cw8ls 1/1 Running 0 69s
tomcat-deployment-79cd69847d-j57r8 1/1 Running 0 69s
tomcat-deployment-79cd69847d-vrh5m 1/1 Running 0 69s
# 查看
[root@k8s-master ~]# kubectl get service -n dev
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
nginx-service ClusterIP None <none> 80/TCP 101s
tomcat-service ClusterIP None <none> 8080/TCP 101s
[root@k8s-master ~]#
6.5.2 Http代理
创建ingress-http.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingress-http
namespace: dev
spec:
ingressClassName: nginx
rules:
- host: nginx.itagan.com
http:
paths:
- pathType: Prefix
path: /
backend:
service:
name: nginx-service
port:
number: 80
- host: tomcat.itagan.com
http:
paths:
- pathType: Prefix
path: /
backend:
service:
name: tomcat-service
port:
number: 8080
# 创建
[root@k8s-master ingress-controller]# pwd
/root/inventory/ingress-controller
[root@k8s-master ingress-controller]# kubectl apply -f ingress-http.yaml
ingress.networking.k8s.io/ingress-http created
[root@k8s-master ingress-controller]#
# 查看
[root@k8s-master ~]# kubectl get ingress -n dev
NAME CLASS HOSTS ADDRESS PORTS AGE
ingress-http <none> nginx.itagan.com,tomcat.itagan.com 80 35s
[root@k8s-master ~]#
# 查看详情
[root@k8s-master ~]# kubectl describe ingress ingress-http -n dev
Name: ingress-http
Labels: <none>
Namespace: dev
Address:
Ingress Class: <none>
Default backend: <default>
Rules:
Host Path Backends
---- ---- --------
nginx.itagan.com
/ nginx-service:80 (10.244.1.146:80,10.244.1.147:80,10.244.2.127:80)
tomcat.itagan.com
/ tomcat-service:8080 (10.244.1.145:8080,10.244.2.128:8080,10.244.2.129:8080)
Annotations: <none>
Events: <none>
[root@k8s-master ~]#
# 接下来,在本地电脑上配置host文件,解析上面的两个域名到10.10.10.148(k8s-master)上
# 然后,就可以分别访问 tomcat.itagan.com:30433 和 nginx.itagan.com:30433 查看效果了
6.5.3 Https代理
创建证书
# 生成证书
[root@k8s-master ingress-controller]# pwd
/root/inventory/ingress-controller
[root@k8s-master ingress-controller]# openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout tls.key -out tls.crt -subj "/C=CN/ST=BJ/L=BJ/O=nginx/CN=itagan.com"
# 创建密钥
[root@k8s-master ingress-controller]# kubectl create secret tls tls-secret --key tls.key --cert tls.crt
secret/tls-secret created
[root@k8s-master ingress-controller]# kubectl get secret
NAME TYPE DATA AGE
tls-secret kubernetes.io/tls 2 88s
[root@k8s-master ingress-controller]# kubectl describe secret tls-secret
Name: tls-secret
Namespace: default
Labels: <none>
Annotations: <none>
Type: kubernetes.io/tls
Data
====
tls.crt: 1245 bytes
tls.key: 1708 bytes
[root@k8s-master ingress-controller]#
创建ingress-https.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingress-https
namespace: dev
spec:
ingressClassName: nginx
tls:
- hosts:
- nginx.itagan.com
- tomcat.itagan.com
secretName: tls-secret
rules:
- host: nginx.itagan.com
http:
paths:
- pathType: Prefix
path: "/"
backend:
service:
name: nginx-service
port:
number: 80
- host: tomcat.itagan.com
http:
paths:
- pathType: Prefix
path: "/"
backend:
service:
name: tomcat-service
port:
number: 8080
# 创建
[root@k8s-master ingress-controller]# pwd
/root/inventory/ingress-controller
[root@k8s-master ingress-controller]# kubectl apply -f ingress-https.yaml
ingress.networking.k8s.io/ingress-https created
# 查看
[root@k8s-master ~]# kubectl get ingress -n dev
NAME CLASS HOSTS ADDRESS PORTS AGE
ingress-https nginx nginx.itagan.com,tomcat.itagan.com 10.10.10.149 80, 443 47s
[root@k8s-master ~]#
# 查看详情
[root@k8s-master ~]# kubectl describe ing ingress-https -n dev
Name: ingress-https
Labels: <none>
Namespace: dev
Address: 10.10.10.149
Ingress Class: nginx
Default backend: <default>
TLS:
tls-secret terminates nginx.itagan.com,tomcat.itagan.com
Rules:
Host Path Backends
---- ---- --------
nginx.itagan.com
/ nginx-service:80 (10.244.1.156:80,10.244.1.158:80,10.244.2.144:80)
tomcat.itagan.com
/ tomcat-service:8080 (10.244.1.157:8080,10.244.2.145:8080,10.244.2.146:8080)
Annotations: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Sync 55s (x2 over 66s) nginx-ingress-controller Scheduled for sync
[root@k8s-master ~]#
# 下面可以通过浏览器访问 https://nginx.itagan.com:31612 和 https://tomcat.itagan.com:31612 来查看了
默认情况下，http与https不能共存，访问http时会自动跳转到https上，若想http与https共存，只需在ingress文件中配置以下内容：
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingress-https
namespace: dev
annotations: # 添加
nginx.ingress.kubernetes.io/ssl-redirect: "false" # 添加
spec:
ingressClassName: nginx
tls:
- hosts:
- nginx.itagan.com
- tomcat.itagan.com
secretName: tls-secret
rules:
- host: nginx.itagan.com
http:
paths:
- pathType: Prefix
path: "/"
backend:
service:
name: nginx-service
port:
number: 80
- host: tomcat.itagan.com
http:
paths:
- pathType: Prefix
path: "/"
backend:
service:
name: tomcat-service
port:
number: 8080
http方式：nginx.itagan.com:30433 / tomcat.itagan.com:30433
https方式：https://nginx.itagan.com:31612 / https://tomcat.itagan.com:31612
在访问的时候，如果用curl能成功访问，而在浏览器上却无法访问，则需要在master主机上执行以下命令：
iptables -P FORWARD ACCEPT
文章来源:https://blog.csdn.net/m0_58805648/article/details/135164903
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本文来自互联网用户投稿，该文观点仅代表作者本人，不代表本站立场。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。 如若内容造成侵权/违法违规/事实不符，请联系我的编程经验分享网邮箱：chenni525@qq.com进行投诉反馈，一经查实，立即删除！