1、说明

对于Kubernetes的service,无论是cluster-ip和nodeport均是四层的负载,集群内的服务如何实现七层的负载均衡,这就需要借助于ingress,ingress控制器实现的方式有很多,比如nginx,contour,haproxy,trafik,lstio。几种常用的ingress功能对比和选型可以参考这里www.kubernetes.org.cn/5948.html

ingress-nginx是七层的负载均衡器,负责统一管理外部对k8s cluster中的service的请求。主要包含

  • ingress-nginx-controller:要据用户编写的ingress规则(创建的Ingress的yaml文件),动态的去更改服务的配置文件,并且reload重载使其生效(是自动化的,通过Lua脚本来实现);
  • ingress资源对像:将Nginx的配置抽像成一个Ingress对像
  • Ingress是K8S的标准资源类型之一,也是一种核心资源,它其实就是一种基于域名和URL路径,把用户的请求转发至指定Service资源的规则
  • 可以将集群外部的请求流量,转发至集群内部,从而实现“服务暴露”
  • Ingre控制器是能够为Ingress资源监听某套接字,然后根扰Ingress规则匹配机制路由调度流量的一个组件
  • 参考链接:https://github.com/nginxinc/kubernetes-ingress

总结用ingress好处:
1、同台服务器不同业务不需要再给每个业务映射端口(Nodeport),只需要每台机安装一个ingress,利用ingress反代CluserIP,前端机访问Ingress固定端口
2、添加新业务只需要再创建一个ingress反代新业务的service,再去前端Nginx反代配置servername里面添加一个域名即可以访问新业务,通过不同的域名访问不同的业务,不需要再配反代

2、业务架构图

二进制部署K8s集群第22节addons之安装部署Ingress

3、Ingress访问流程图

二进制部署K8s集群第22节addons之安装部署Ingress

4、架构

二进制部署K8s集群第22节addons之安装部署Ingress
二进制部署K8s集群第22节addons之安装部署Ingress

5、部署traefik

5.1 准备traefik镜像

hdss7-200机主机上操作

docker pull traefik:v1.7-alpine
docker tag c36f69007d98 harbor.od.com/k8s/traefik:v1.7
docker push harbor.od.com/k8s/traefik:v1.7

5.2 准备traefik资源配置清单目录

清单下载地址:https://github.com/traefik/traefik/tree/v1.7/examples/k8s

mkdir -p /data/k8s-yaml/traefik && cd /data/k8s-yaml/traefik

5.3 准备rbac.yaml文件

cat > /data/k8s-yaml/traefik/rbac.yaml <<'eof'
apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
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
eof

5.4 准备daemonset.yaml文件

cat > /data/k8s-yaml/traefik/daemonset.yaml <<'eof'
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
  labels:
    k8s-app: traefik-ingress-lb
spec:
  selector:
    matchLabels:
      k8s-app: traefik-ingress-lb
  template:
    metadata:
      labels:
        k8s-app: traefik-ingress-lb
        name: traefik-ingress-lb
    spec:
      serviceAccountName: traefik-ingress-controller
      terminationGracePeriodSeconds: 60
      containers:
      - image: harbor.od.com/k8s/traefik:v1.7
        name: traefik-ingress-lb
        ports:
        - name: http
          containerPort: 80
          hostPort: 81
              - name: web-admin
          containerPort: 8080
          hostPort: 8081
        securityContext:
          capabilities:
            drop:
            - ALL
            add:
            - NET_BIND_SERVICE
        args:
        - --api
        - --kubernetes
        - --logLevel=INFO
        - --insecureskipverify=true
        - --kubernetes.endpoint=https://10.4.7.10:7443
        - --accesslog
        - --accesslog.filepath=/var/log/traefik_access.log
        - --traefiklog
        - --traefiklog.filepath=/var/log/traefik.log
        - --metrics.prometheus
      imagePullSecrets:
      - name: harbor
eof

hostPort: 81 为ingress的程序80端口映射到宿主机供提供访问的端口

5.5 安装ingress

kubectl apply -f http://k8s-yaml.od.com/traefik/rbac.yaml 
kubectl apply -f http://k8s-yaml.od.com/traefik/daemonset.yaml 

6 创建nginx资源清单目录

mkdir /data/k8s-yaml/nginxtest

7 创建ingress.yml

cat > /data/k8s-yaml/nginxtest/ingress.yml <<'eof'
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-web
  namespace: default
  annotations:
    kubernetes.io/ingress.class: traefik
spec:
  rules:
  - host: nginxtest.od.com
    http:
      paths:
        - path: /
          backend:
            serviceName: nginx-test
            servicePort: 80
eof

主机名为nginxtest.od.com,反代到svc的name为nginx-test,路径为/,端口80

8 创建svc.yml

cat > /data/k8s-yaml/nginxtest/svc.yml <<'eof'
apiVersion: v1
kind: Service
metadata:
  labels:
    k8s-app: nginx-test
  name: nginx-test
  namespace: default
spec:
  ports:
    - port: 80
      protocol: TCP
  selector:
    app: nginx-test
  sessionAffinity: None
eof

svc标签选择器app: nginx-test,反代pod为app:nginx-test

9 创建deploy.yml

cat > /data/k8s-yaml/nginxtest/deploy.yml <<'eof'
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-test
  labels:
    app: nginx-test
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx-test
  template:
    metadata:
      labels:
        app: nginx-test
    spec:
      containers:
      - name: nginx-test
        image: harbor.od.com/public/nginx:v1.7.9
        ports:
        - name: web
          containerPort: 80

10 添加dns解析

hdss7-11.host.com上操作

cat >> /var/named/od.com.zone <<'eof'
nginxtest          A    10.4.7.10
eof
vi /var/named/od.com.zone
2020100504  ; serial # 日期加1
systemctl restart named

11 配置7层负载

在hdss7-11.host.com和hdss7-12.host.com上操作

cat >/etc/nginx/conf.d/nginxtest.com.conf <<'eof'
upstream default_backend_traefik {
    server 10.4.7.21:81    max_fails=3 fail_timeout=10s;
    server 10.4.7.22:81    max_fails=3 fail_timeout=10s;
}
server {
    server_name nginxtest.od.com;

    location / {
        proxy_pass http://default_backend_traefik;
        proxy_set_header Host       $http_host;
        proxy_set_header x-forwarded-for $proxy_add_x_forwarded_for;
    }
}
eof
nginx -s reload

12 应用资源配置清单

以下都在hdss7-21.host.com或hdss7-22上操作

[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/nginxtest/deploy.yml
[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/nginxtest/svc.yml
[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/nginxtest/ingress.yml
[root@hdss7-22 ~]# kubectl get ing
Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress
NAME        CLASS    HOSTS              ADDRESS   PORTS   AGE
nginx-web   <none>   nginxtest.od.com             80      18h
[root@hdss7-22 ~]# kubectl get pods -n kube-system -o wide           
NAME                               READY   STATUS    RESTARTS   AGE   IP           NODE                NOMINATED NODE   READINESS GATES
coredns-57c78bdbcd-lsf5z           1/1     Running   4          30h   172.7.21.3   hdss7-21.host.com   <none>           <none>
traefik-ingress-controller-9n8zb   1/1     Running   0          11h   172.7.21.5   hdss7-21.host.com   <none>           <none>
traefik-ingress-controller-wxnqw   1/1     Running   0          11h   172.7.22.4   hdss7-22.host.com   <none>           <none>

13 修改html

[root@hdss7-22 ~]# kubectl get pods -o wide                          
NAME                          READY   STATUS    RESTARTS   AGE   IP           NODE                NOMINATED NODE   READINESS GATES
nginx-test-558df79dc9-d95rp   1/1     Running   0          9h    172.7.21.2   hdss7-21.host.com   <none>           <none>
nginx-test-558df79dc9-qw2fj   1/1     Running   0          9h    172.7.22.2   hdss7-22.host.com   <none>           <none>
[root@hdss7-22 ~]# kubectl exec -it nginx-test-558df79dc9-d95rp -- /bin/bash
root@nginx-test-558df79dc9-d95rp:/# echo WEB1 > /usr/share/nginx/html/index.html
root@nginx-test-558df79dc9-d95rp:/# exit
exit
[root@hdss7-22 ~]# kubectl exec -it nginx-test-558df79dc9-qw2fj -- /bin/bash     
root@nginx-test-558df79dc9-qw2fj:/# echo WEB2 > /usr/share/nginx/html/index.html

14 WEB访问

二进制部署K8s集群第22节addons之安装部署Ingress
二进制部署K8s集群第22节addons之安装部署Ingress