《Windows Azure Platform 系列文章目录》
最近有1个客户需求，在这里记录一下。
客户提出需要使用Azure负载均衡器(四层负载均衡器)，实现主备模式。
场景是负载均衡器后有2台虚拟机
- 平时100%的流量都发送到第一台虚拟机
- 如果第一台虚拟机发生宕机了，则100%的流量都发送到第二台虚拟机
- 如果第一台虚拟机恢复正常，则100%的流量重新发送到第一台虚拟机上。
首先说明一下：
1.Azure四层负载均衡器的规则，有三种：
(1)无。指定来自同一客户端的连续请求可由任意虚拟机处理
(2)客户端IP。制定来自同一客户端 IP 地址的连续请求，将发送到同一个虚拟机处理
(3)客户端IP和协议。指定来自同一客户端 IP 地址和协议组合的连续请求，将发送到同一个虚拟机处理、
2.我们这里主要通过在虚拟机里部署HAProxy的方式，在HAProxy部署主备。
准备环境：
1.我们先创建1个新的虚拟网络，名称为：testing-vnet，设置IP Range为：10.0.0.0/16
2.在这个虚拟网络里，创建2个子网：
- 第一个子网名称为：haproxyvm-subnet，IP Range为10.0.0.0/24
- 第二个子网名称为：nginxvm-subnet，IP Range为10.0.1.0/24
3.创建4台虚拟机，具体配置如下：
| 虚拟机名称 | 虚拟机大小 | 操作系统 | 虚拟网络 | 子网 | 公网IP | 内网IP |
| haproxyvm-01 | 2Core/4GB | CentOS 8.2 | testing-vnet | haproxyvm-subnet | 略 | 10.0.0.4 |
| haproxyvm-02 | 2Core/4GB | CentOS 8.2 | testing-vnet | haproxyvm-subnet | 略 | 10.0.0.5 |
| nginxvm-01 | 2Core/4GB | CentOS 8.2 | testing-vnet | nginxvm-subnet | 略 | 10.0.1.4 |
| nginxvm-02 | 2Core/4GB | CentOS 8.2 | testing-vnet | nginxvm-subnet | 略 | 10.0.1.5 |
准备安装Nginx虚拟机
1.我们先登录nginxvm-01这台虚拟机，先切换到root身份
sudo su -
2.通过yum安装nginx
yum install nginx -y
3.进入到nginx的html页面
cd /usr/share/nginx/html
4.备份默认的html页面
cp index.html index.html.bak
5.修改默认的html页面，显示为当前的虚拟机名称
echo "This is nginxvm-01" > index.html
6.启动nginx服务
systemctl start nginx
7.设置nginx开机启动
systemctl enable nginx
8.测试当前的nginx页面
[root@nginxvm-01 html]# curl localhost This is nginxvm-01
9.最后我们在nginxvm-02这台虚拟机上，执行上面的步骤1-4。同时修改默认的html页面，
echo "This is nginxvm-02" > index.html
10.在nginxvm-02上，执行上面的步骤6-8
准备安装HAProxy
1.我们先登录haproxyvm-01这台虚拟机，先切换到root身份
sudo su -
2.安装haproxy
yum install haproxy -y
3.进入haproxy配置路径
cd /etc/haproxy
4.备份haproxy配置信息
cp haproxy.cfg haproxy.cfg.bak
5.编辑haproxy.cfg，主要修改的内容我用中文备注了
#--------------------------------------------------------------------- # Example configuration for a possible web application. See the # full configuration options online. # # https://www.haproxy.org/download/1.8/doc/configuration.txt # #--------------------------------------------------------------------- #--------------------------------------------------------------------- # Global settings #--------------------------------------------------------------------- global # to have these messages end up in /var/log/haproxy.log you will # need to: # # 1) configure syslog to accept network log events. This is done # by adding the '-r' option to the SYSLOGD_OPTIONS in # /etc/sysconfig/syslog # # 2) configure local2 events to go to the /var/log/haproxy.log # file. A line like the following can be added to # /etc/sysconfig/syslog # # local2.* /var/log/haproxy.log # log 127.0.0.1 local2 chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 4000 user haproxy group haproxy daemon # turn on stats unix socket stats socket /var/lib/haproxy/stats # utilize system-wide crypto-policies ssl-default-bind-ciphers PROFILE=SYSTEM ssl-default-server-ciphers PROFILE=SYSTEM #--------------------------------------------------------------------- # common defaults that all the 'listen' and 'backend' sections will # use if not designated in their block #--------------------------------------------------------------------- defaults mode http log global option httplog option dontlognull option http-server-close option forwardfor except 127.0.0.0/8 option redispatch retries 1 #1次链接失败就认为服务器不可用 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000 #--------------------------------------------------------------------- # main frontend which proxys to the backends #--------------------------------------------------------------------- frontend main bind *:5000 #设置监听端口为5000 acl url_static path_beg -i /static /images /javascript /stylesheets acl url_static path_end -i .jpg .gif .png .css .js use_backend static if url_static default_backend app #--------------------------------------------------------------------- # static backend for serving up images, stylesheets and such #--------------------------------------------------------------------- backend static balance roundrobin server static 127.0.0.1:4331 check #--------------------------------------------------------------------- # round robin balancing between the various backends #--------------------------------------------------------------------- backend app balance roundrobin server app1 10.0.1.4:80 check #这里的10.0.1.4是nginxvm-01虚拟机的内网IP地址，check表示是主节点 server app2 10.0.1.5:80 backup #这里的10.0.1.5是nginxvm-02虚拟机的内网IP地址，backup表示是备份节点
6.主要修改的内容如下：
retries 1 #1次链接失败就认为服务器不可用 frontend main bind *:5000 #设置监听端口为5000 server app1 10.0.1.4:80 check #这里的10.0.1.4是nginxvm-01虚拟机的内网IP地址,80端口是Nginx使用，check表示是主节点 server app2 10.0.1.5:80 backup #这里的10.0.1.5是nginxvm-02虚拟机的内网IP地址,80端口是Nginx使用，backup表示是备份节点
上面的frontend main里面bind，表示请求haproxyvm前端的5000端口，会转发到nginxvm的80端口
7.启动haproxy
systemctl start haproxy
8.设置开机启动
systemctl enable haproxy
9.请记得登录haproxyvm-02，设置把上面的步骤1-8再设置一次，并且配置haproxy.cfg的信息和haproxyvm-01完全一致
最后，我们创建1个公网负载均衡器(内网负载均衡器也可以，这里笔者为了演示方便)
1.创建公网负载均衡器步骤略。公网负载均衡器的IP地址为：48.218.194.204
2.负载均衡器的后端池，我们选择haproxyvm-01和haproxyvm-02的内网网卡：IP分别是10.0.0.4和10.0.0.5。截图略
3.负载均衡器的监听，名称为probe5000，我们设置监听端口为5000，协议为TCP
4.设置负载均衡器规则：
- Port为80，这里的port是指internet到负载均衡器的端口
- Backend Port为5000，这里的backendport是指负载均衡器，到后端haproxyvm的端口
- Health Probe选择之前创建的监听：probe5000
- Session persistence设置为None
5.最后请记得在haproxyvm-01和haproxyvm-02的安全组上，打开端口5000的Inbound访问
测试
1.我们在本地笔记本上，执行命令。下面的48.218.194.204，是我的负载均衡器的公网IP地址
while true; do curl http://48.218.194.204; sleep 1; done
2.可以观察到，所有的请求经过2台Haproxy虚拟机，都发送到nginxvm-01上，如下图：
root@Leilaptop6:~# while true; do curl http://48.218.194.204; sleep 1; done This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01
3.然后我们ssh到nginxvm-01上，关闭nginx服务
[root@nginxvm-01 html]# systemctl stop nginx
4.观察curl结果：
root@Leilaptop6:~# while true; do curl http://48.218.194.204; sleep 1; done This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-02 This is nginxvm-02 This is nginxvm-02 This is nginxvm-02 This is nginxvm-02
5.然后我们在nginxvm-01上，重新启动nginx服务
[root@nginxvm-01 html]# systemctl start nginx
6.观察curl结果：
This is nginxvm-02 This is nginxvm-02 This is nginxvm-02 This is nginxvm-02 This is nginxvm-02 This is nginxvm-02 This is nginxvm-02 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01 This is nginxvm-01
截图如下：
可以看到当nginxvm-01恢复服务后，100%流量又重新发送到nginxvm-01了。
参考文档：https://blog.csdn.net/qq_41124528/article/details/129571483
