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四层负载均衡调度器service回顾
使用四层负载均衡调度器service时，当客户端访问kubernetes集群内部的应用时，数据包走向如下面流程所示
client--->nodeip:port--->service ip:port--->podip:port
客户端-->node节点的ip:端口--->service的ip:端口--->pod的ip:端口1.Ingress Controller
Ingress Controller是一个七层负载均衡调度器，客户端的请求先到达这个七层负载均衡调度器，由七层负载均衡器在反向代理到后端pod，常见的七层负载均衡器有nginx，traefik等，以我们熟悉的nginx为例，假如请求到达nginx，会通过upstream反向代理到后端pod，但是后端pod的ip地址是一直在变化的，因此在后端pod前需要加一个service，这个service只是起到分组的作用，那么我们upstream只需要填写service地址即可
nginx：需要手动加载配置文件
traefik：定期自动加载配置文件，不需要手动干预，在微服务中几乎都会使用这种调度器
2.Ingress
官方：https://kubernetes.io/docs/concepts/services-networking/ingress/
ingress官网定义：ingress可以把进入到集群内部的请求转发到集群中的一些服务上，从而可以把服务暴漏到集群外部。Ingress 能把集群内Service 配置成外网能够访问的 URL，流量负载均衡，提供基于域名访问的虚拟主机等；ingress是k8s中的资源，当service关联的后端pod ip地址发生变化，就会把这些变化信息保存在ingress中，由ingress注入到七层负载均衡调度器ingress controller中，也就是把信息传入到七层负载均衡调度器的配置文件中，并且重新加载使配置生效，Ingress 可以用来规定 HTTP/S 请求应该被转发到哪个 Service 上，比如根据请求中不同的 Host 和 url 路径让请求落到不同的 Service 上
总结：
Ingress Controller：
Ingress Controller 可以理解为控制器，它通过不断的跟 Kubernetes API 交互，实时获取后端Service、Pod的变化，比如新增、删除等，结合Ingress 定义的规则生成配置，然后动态更新上边的 Nginx 或者trafik负载均衡器，并刷新使配置生效，来达到服务自动发现的作用。
Ingress：
Ingress 则是定义规则，通过它定义某个域名的请求过来之后转发到集群中指定的 Service。它可以通过 Yaml 文件定义，可以给一个或多个 Service 定义一个或多个 Ingress 规则。
3.七层调度器traefik
如果七层负载均衡调度器使用nginx，那么每次nginx配置文件修改之后，都需要重新reload才能生效，很不方便，如果使用traefik或者Envoy，可以每隔一定时间重新加载配置文件，不需要手动重新加载，对于这种微服务架构来说特别方便
4.使用七层负载均衡调度器的步骤
（1）部署ingress controller，我们ingress controller使用的是traefik
（2）创建service，用来分组pod
（3）创建pod应用，可以通过控制器创建pod
（4）创建ingress http，测试通过http访问
（5）创建ingress https，测试通过https访问
5.客户端通过七层调度器访问后端pod的方式
使用七层负载均衡调度器ingress controller时，当客户端访问kubernetes集群内部的应用时，数据包走向如下面流程所示：
client--->Nodeip:port----->IngressController--->service--->pod
6.生成证书，在k8s集群的master节点操作
（1）生成私钥
openssl genrsa -out tls.key 2048
（2）生成证书
openssl req -new -x509 -key tls.key -out tls.crt -subj /C=CN/ST=Beijing/O=DevOps/CN=tomcat.lucky.com
（3）生成secret
kubectl create secret tls tomcat-ingress-secret --cert=tls.crt --key=tls.key
Secret 对象类型用来保存敏感信息，例如密码、OAuth 令牌和 ssh key。将这些信息放在 secret 中比放在 pod 的定义或者 docker 镜像中来说更加安全和灵活
kubectl get secret 显示如下：
7.部署trafik，在k8s集群的master节点操作
（1）生成openssl.cnf文件，这个文件里面把签发证书时需要的参数已经定义好了
mkdir /root/test
echo """
[req]
distinguished_name = req_distinguished_name
prompt = yes
[ req_distinguished_name ]
countryName = Country Name (2 letter code)
countryName_value = CN
stateOrProvinceName = State or Province Name (full name)
stateOrProvinceName_value = Beijing
localityName = Locality Name (eg, city)
localityName_value = Haidian
organizationName = Organization Name (eg, company)
organizationName_value = Channelsoft
organizationalUnitName = Organizational Unit Name (eg, section)
organizationalUnitName_value = R & D Department
commonName = Common Name (eg, your name or your server\'s hostname)
commonName_value = *.multi.io
emailAddress = Email Address
emailAddress_value = [email protected]
""" > /root/test/openssl.cnf
（2）生成一个证书
openssl req -newkey rsa:4096 -nodes -config /root/test/openssl.cnf -days 3650 -x509 -out /root/test/tls.crt -keyout /root/test/tls.key
（3）创建一个secret对象
kubectl create -n kube-system secret tls ssl --cert /root/test/tls.crt --key /root/test/tls.key
（4）部署traefik
cat traefik.yaml
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: traefik-ingress-controller
rules:
- apiGroups:
- ""
resources:
- services
- endpoints
- secrets
verbs:
- get
- list
- watch
- apiGroups:
- extensions
resources:
- ingresses
verbs:
- get
- list
- watch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: traefik-ingress-controller
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: traefik-ingress-controller
subjects:
- kind: ServiceAccount
name: traefik-ingress-controller
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: traefik-ingress-controller
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: traefik-conf
namespace: kube-system
data:
traefik.toml: |
insecureSkipVerify = true
defaultEntryPoints = ["http","https"]
[entryPoints]
[entryPoints.http]
address = ":80"
[entryPoints.https]
address = ":443"
[entryPoints.https.tls]
[[entryPoints.https.tls.certificates]]
CertFile = "/ssl/tls.crt"
KeyFile = "/ssl/tls.key"
---
kind: DaemonSet
apiVersion: apps/v1
metadata:
name: traefik-ingress-controller
namespace: kube-system
labels:
k8s-app: traefik-ingress-lb
spec:
selector:
matchLabels:
k8s-app: traefik-ingress-lb
name: traefik-ingress-lb
template:
metadata:
labels:
k8s-app: traefik-ingress-lb
name: traefik-ingress-lb
spec:
serviceAccountName: traefik-ingress-controller
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
terminationGracePeriodSeconds: 60
hostNetwork: true
volumes:
- name: ssl
secret:
secretName: ssl
- name: config
configMap:
name: traefik-conf
containers:
- image: k8s.gcr.io/traefik:1.7.9
name: traefik-ingress-lb
ports:
- name: http
containerPort: 80
hostPort: 80
- name: admin
containerPort: 8080
securityContext:
privileged: true
args:
- --configfile=/config/traefik.toml
- -d
- --web
- --kubernetes
volumeMounts:
- mountPath: "/ssl"
name: "ssl"
- mountPath: "/config"
name: "config"
---
kind: Service
apiVersion: v1
metadata:
name: traefik-ingress-service
spec:
selector:
k8s-app: traefik-ingress-lb
ports:
- protocol: TCP
port: 80
name: web
- protocol: TCP
port: 8080
name: admin
- protocol: TCP
port: 443
name: https
type: NodePort
---
apiVersion: v1
kind: Service
metadata:
name: traefik-web-ui
namespace: kube-system
spec:
selector:
k8s-app: traefik-ingress-lb
ports:
- port: 80
targetPort: 8080
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: traefik-web-ui
namespace: kube-system
annotations:
kubernetes.io/ingress.class: traefik
spec:
rules:
- host: ingress.multi.io
http:
paths:
- backend:
serviceName: traefik-web-ui
servicePort: 80
把traefik镜像traefik_1_7_9.tar.gz上传到k8s各个节点，手动解压：
docker load -i traefik_1_7_9.tar.gz
镜像地址：
链接：https://pan.baidu.com/s/1fTRc0J0iL7DeAH_LNUkTQQ
提取码：xg1z
kubectl apply -f traefik.yaml
（5）验证traefik部署是否成功
kubectl get pods -n kube-system 显示如下，说明部署成功
traefik-ingress-controller-g45th 1/1 Running 0 9m2s
traefik-ingress-controller-lj9md 1/1 Running 0 9m2s
8.部署tomcat
cat tomcat-deploy.yaml
apiVersion: v1
kind: Service
metadata:
name: tomcat
namespace: default
spec:
selector:
app: tomcat
release: canary
ports:
- name: http
targetPort: 8080
port: 80
- name: ajp
targetPort: 8009
port: 8009
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: tomcat-deploy
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: tomcat
release: canary
template:
metadata:
labels:
app: tomcat
release: canary
spec:
containers:
- name: myapp
image: tomcat:8.5-jre8-alpine
ports:
- name: http
containerPort: 8080
- name: ajp
containerPort: 8009kubectl apply -f tomcat-deploy.yaml
kubectl get pods 显示如下，说明部署成功
tomcat-deploy-59664bcb6f-5z4nn 1/1 Running 0 20s
tomcat-deploy-59664bcb6f-cgjbn 1/1 Running 0 20s
tomcat-deploy-59664bcb6f-n4tqq 1/1 Running 0 20s
9.部署tomcat http
cat ingress-tomcat.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-tomcat
namespace: default
annotations:
kubernetes.io/ingress.class: "traefik"
spec:
rules:
- host: tomcat.lucky.com
http:
paths:
- path:
backend:
serviceName: tomcat
servicePort: 80kubectl apply -f ingress-tomcat.yaml
10.部署tomcat https
cat ingress-tomcat-tls.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-tomcat-tls
namespace: default
annotations:
kubernetes.io/ingress.class: traefik
spec:
tls:
- hosts:
- tomcat.lucky.com
secretName: tomcat-ingress-secret
rules:
- host: tomcat.lucky.com
http:
paths:
- path:
backend:
serviceName: tomcat
servicePort: 80kubectl apply -f ingress-tomcat-tls.yaml
kubectl get ingress
显示如下：
NAME HOSTS ADDRESS PORTS AGE
ingress-tomcat tomcat.lucky.com 80 103s
ingress-tomcat-tls tomcat.lucky.com 80, 443 8s
11.配置自己电脑的hosts文件
192.168.0.16 tomcat.lucky.com
12.在浏览器访问：
https://tomcat.lucky.com:443
或者http://tomcat.lucky.com
可看到如下界面，说明https配置成功
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微信：luckylucky421302
