Kubernetes学习笔记（三）：Service与Ingress
一、Service详解
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
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 cm kube-proxy -n kube-system
# 修改mode: "ipvs"
[root@k8s-master ~]# kubectl delete pod -l k8s-app=kube-proxy -n kube-system
[root@node1 ~]# ipvsadm -Ln
TCP 10.97.97.97:80 rr
-> 10.244.1.22:80 Masq 1 0 0
-> 10.244.2.15:80 Masq 1 0 0
-> 10.244.2.16:80 Masq 1 0 0
2、Service类型
Service的资源清单文件：
kind: Service # 资源类型
apiVersion: v1 # 资源版本
metadata: # 元数据
name: service # 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
3、Service使用
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: nginx-pod的标签
创建deployment.yaml文件，内容如下：
apiVersion: apps/v1
kind: Deployment
metadata:
name: pc-deployment
namespace: dev
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
# 创建deployment
[root@k8s-master ~]# kubectl create -f deployment.yaml
deployment.apps/pc-deployment created
# 查看pod详情
[root@k8s-master ~]# kubectl get pod -n dev -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pc-deployment-7d7dd5499b-dx4zd 1/1 Running 0 9s 10.244.2.15 k8s-node2 <none> <none>
pc-deployment-7d7dd5499b-vsk56 1/1 Running 0 9s 10.244.2.16 k8s-node2 <none> <none>
pc-deployment-7d7dd5499b-x94dv 1/1 Running 0 9s 10.244.1.22 k8s-node1 <none> <none>
# 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 pc-deployment-7d7dd5499b-dx4zd -n dev /bin/sh
# echo "10.244.2.15" > /usr/share/nginx/html/index.html
# 修改完毕之后，访问测试
[root@k8s-master ~]# curl 10.244.2.15
10.244.2.15
[root@k8s-master ~]# curl 10.244.2.16
10.244.2.16
[root@k8s-master ~]# curl 10.244.1.22
10.244.1.22
2）、ClusterIP类型的Service
创建service-clusterip.yaml文件，内容如下：
apiVersion: v1
kind: Service
metadata:
name: service-clusterip
namespace: dev
spec:
selector:
app: nginx-pod
clusterIP: 10.97.97.97 # 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 ~]# kubectl create -f service-clusterip.yaml
service/service-clusterip created
# 查看service
[root@k8s-master ~]# kubectl get svc service-clusterip -n dev -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service-clusterip ClusterIP 10.97.97.97 <none> 80/TCP 20s app=nginx-pod
# 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 ~]# kubectl describe svc service-clusterip -n dev
Name: service-clusterip
Namespace: dev
Labels: <none>
Annotations: <none>
Selector: app=nginx-pod
Type: ClusterIP
IP: 10.97.97.97
Port: <unset> 80/TCP
TargetPort: 80/TCP
Endpoints: 10.244.1.22:80,10.244.2.15:80,10.244.2.16:80
Session Affinity: None
Events: <none>
# 查看ipvs的映射规则
[root@k8s-master ~]# ipvsadm -Ln
TCP 10.97.97.97:80 rr
-> 10.244.1.22:80 Masq 1 0 0
-> 10.244.2.15:80 Masq 1 0 0
-> 10.244.2.16:80 Masq 1 0 0
# 循环访问测试
[root@k8s-master ~]# while true;do curl 10.97.97.97:80; sleep 1; done;
10.244.1.22
10.244.2.15
10.244.2.16
10.244.1.22
10.244.2.15
10.244.2.16
Endpoints
Endpoints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
只有处于Running状态，且readinessProbe检查通过的Pod，才会出现在Service的Endpoints列表里。并且，当某一个Pod出现问题时，Kubernetes会自动把它从Service里摘除掉
# 查看endpoints
[root@k8s-master ~]# kubectl get endpoints -n dev
NAME ENDPOINTS AGE
service-clusterip 10.244.1.22:80,10.244.2.15:80,10.244.2.16:80 5m10s
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
# 修改分发策略 sessionAffinity:ClientIP
# 查看ipvs规则【persistent 代表持久】
[root@k8s-master ~]# ipvsadm -Ln
TCP 10.97.97.97:80 rr persistent 10800
-> 10.244.1.22:80 Masq 1 0 0
-> 10.244.2.15:80 Masq 1 0 0
-> 10.244.2.16:80 Masq 1 0 0
# 循环访问测试
[root@k8s-master ~]# while true;do curl 10.97.97.97:80; sleep 1; done;
10.244.1.22
10.244.1.22
10.244.1.22
# 删除service
[root@k8s-master ~]# kubectl delete -f service-clusterip.yaml
service "service-clusterip" deleted
3）、Headless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Headless 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-headless.yaml文件，内容如下：
apiVersion: v1
kind: Service
metadata:
name: service-headless
namespace: dev
spec:
selector:
app: nginx-pod
clusterIP: None # 将clusterIP设置为None，即可创建headless Service
type: ClusterIP
ports:
- port: 80
targetPort: 80
# 创建service
[root@k8s-master ~]# kubectl create -f service-headless.yaml
service/service-headless created
# 获取service，发现CLUSTER-IP未分配
[root@k8s-master ~]# kubectl get svc service-headless -n dev -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service-headless ClusterIP None <none> 80/TCP 33s app=nginx-pod
# 查看service详情
[root@k8s-master ~]# kubectl describe svc service-headless -n dev
Name: service-headless
Namespace: dev
Labels: <none>
Annotations: <none>
Selector: app=nginx-pod
Type: ClusterIP
IP: None
Port: <unset> 80/TCP
TargetPort: 80/TCP
Endpoints: 10.244.1.22:80,10.244.2.15:80,10.244.2.16:80
Session Affinity: None
Events: <none>
[root@k8s-master ~]# kubectl get pod -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-7d7dd5499b-dx4zd 1/1 Running 0 33m
pc-deployment-7d7dd5499b-vsk56 1/1 Running 0 33m
pc-deployment-7d7dd5499b-x94dv 1/1 Running 0 33m
# 查看域名的解析情况
[root@k8s-master ~]# kubectl exec -it pc-deployment-7d7dd5499b-dx4zd -n dev /bin/sh
# cat /etc/resolv.conf
nameserver 10.96.0.10
search dev.svc.cluster.local svc.cluster.local cluster.local lan
[root@k8s-master ~]# yum install -y bind-utils
# 默认是service name+dev.svc.cluster.local
[root@k8s-master ~]# dig @10.96.0.10 service-headless.dev.svc.cluster.local
service-headless.dev.svc.cluster.local. 30 IN A 10.244.2.16
service-headless.dev.svc.cluster.local. 30 IN A 10.244.2.15
service-headless.dev.svc.cluster.local. 30 IN A 10.244.1.22
4）、NodePort类型的Service
在之前的实例中，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文件，内容如下：
apiVersion: v1
kind: Service
metadata:
name: service-nodeport
namespace: dev
spec:
selector:
app: nginx-pod
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 ~]# kubectl create -f service-nodeport.yaml
service/service-nodeport created
# 查看service
[root@k8s-master ~]# kubectl get svc service-nodeport -n dev -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service-nodeport NodePort 10.109.137.7 <none> 80:30002/TCP 14s app=nginx-pod
# 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
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）、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
创建service-externalname.yaml文件，内容如下：
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 ~]# kubectl create -f service-externalname.yaml
service/service-externalname created
# 查看service
[root@k8s-master ~]# kubectl get svc service-externalname -n dev
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service-externalname ExternalName <none> www.baidu.com <none> 17s
# 域名解析
[root@k8s-master ~]# dig @10.96.0.10 service-externalname.dev.svc.cluster.local
service-externalname.dev.svc.cluster.local. 30 IN CNAME www.baidu.com.
www.baidu.com. 30 IN CNAME www.a.shifen.com.
www.a.shifen.com. 30 IN A 180.101.49.12
www.a.shifen.com. 30 IN A 180.101.49.11
二、Ingress
1、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LB，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、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
一个Nginx Ingress Controller提供的服务，其实是一个可以根据Ingress对象和被代理后端Service的变化，来自动进行更新的Nginx负载均衡器
2、Ingress使用
1）、环境准备
1）搭建Ingress环境
[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
mandatory.yaml文件内容如下：
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 "-"
# Here: "-"
# 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:
# 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: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.30.0
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
service-nodeport.yaml文件内容如下：
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
---
# 修改mandatory.yaml文件中的仓库
# 修改quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.30.0
# 为quay-mirror.qiniu.com/kubernetes-ingress-controller/nginx-ingress-controller:0.30.0
# 创建ingress-nginx
[root@k8s-master ingress-controller]# kubectl apply -f ./
# 查看ingress-nginx
[root@k8s-master ingress-controller]# kubectl get pod -n ingress-nginx
NAME READY STATUS RESTARTS AGE
nginx-ingress-controller-5bb8fb4bb6-4x4kx 1/1 Running 0 28s
# 查看service
[root@k8s-master ingress-controller]# kubectl get svc -n ingress-nginx
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
ingress-nginx NodePort 10.101.45.148 <none> 80:30721/TCP,443:32240/TCP 40s
2）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文件，内容如下：
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:1.17.1
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:8.5-jre10-slim
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
[root@k8s-master ~]# kubectl create -f tomcat-nginx.yaml
[root@k8s-master ~]# kubectl get svc -n dev
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
nginx-service ClusterIP None <none> 80/TCP 112s
tomcat-service ClusterIP None <none> 8080/TCP 112s
2）、Http代理
创建ingress-http.yaml文件，内容如下：
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-http
namespace: dev
spec:
rules:
- host: nginx.ppdai.com
http:
paths:
- path: /
backend:
serviceName: nginx-service
servicePort: 80
- host: tomcat.ppdai.com
http:
paths:
- path: /
backend:
serviceName: tomcat-service
servicePort: 8080
# 创建
[root@k8s-master ~]# kubectl create -f ingress-http.yaml
# 查看
[root@k8s-master ~]# kubectl get ing ingress-http -n dev
NAME CLASS HOSTS ADDRESS PORTS AGE
ingress-http <none> nginx.ppdai.com,tomcat.ppdai.com 10.101.45.148 80 21s
# 查看详情
[root@k8s-master ~]# kubectl describe ing ingress-http -n dev
Name: ingress-http
Namespace: dev
Address: 10.101.45.148
Default backend: default-http-backend:80 (<error: endpoints "default-http-backend" not found>)
Rules:
Host Path Backends
---- ---- --------
nginx.ppdai.com
/ nginx-service:80 (10.244.1.25:80,10.244.1.26:80,10.244.2.17:80)
tomcat.ppdai.com
/ tomcat-service:8080 (10.244.1.27:8080,10.244.2.18:8080,10.244.2.19:8080)
Annotations: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal CREATE 54s nginx-ingress-controller Ingress dev/ingress-http
Normal UPDATE 36s nginx-ingress-controller Ingress dev/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192.168.56.23(master)上
# 然后，就可以分别访问tomcat.ppdai.com:30721(ingress-nginx的http端口)和nginx.ppdai.com:30721查看效果
3）、Https代理
创建证书
# 生成证书
[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/O=nginx/CN=ppdai.com"
# 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ingress-https.yaml文件，内容如下：
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-https
namespace: dev
spec:
tls:
- hosts:
- nginx.ppdai.com
- tomcat.ppdai.com
secretName: tls-secret # 指定秘钥
rules:
- host: nginx.ppdai.com
http:
paths:
- path: /
backend:
serviceName: nginx-service
servicePort: 80
- host: tomcat.ppdai.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 ingress-https -n dev
NAME CLASS HOSTS ADDRESS PORTS AGE
ingress-https <none> nginx.ppdai.com,tomcat.ppdai.com 10.101.45.148 80, 443 16s
# 查看详情
[root@k8s-master ~]# kubectl describe ing ingress-https -n dev
Name: ingress-https
Namespace: dev
Address: 10.101.45.148
Default backend: default-http-backend:80 (<error: endpoints "default-http-backend" not found>)
TLS:
tls-secret terminates nginx.ppdai.com,tomcat.ppdai.com
Rules:
Host Path Backends
---- ---- --------
nginx.ppdai.com
/ nginx-service:80 (10.244.1.25:80,10.244.1.26:80,10.244.2.17:80)
tomcat.ppdai.com
/ tomcat-service:8080 (10.244.1.27:8080,10.244.2.18:8080,10.244.2.19:8080)
Annotations: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal CREATE 46s nginx-ingress-controller Ingress dev/ingress-https
Normal UPDATE 43s nginx-ingress-controller Ingress dev/ingress-https
# 下面可以通过浏览器访问https://nginx.ppdai.com:32240(ingress-nginx的https端口)和https://tomcat.ppdai.com:32240来查看
参考：
Kubernetes(K8S) 入门进阶实战完整教程，黑马程序员K8S全套教程（基础+高级）
极客时间 《深入剖析Kubernetes》