单主模型

环境四个虚拟机

upstream server:node1:172.16.100.6         CeotOS 6

upstream server:node3:172.16.100.69         CeotOS 7

节点1:172.16.100.67                        CeotOS 7

节点2:node2:172.16.100.68                       CeotOS 7

节1&2

# yum install nginx -y

# cd /etc/nginx

# vim nginx.conf

                      include /etc/nginx/conf.d/*.conf;
                      upstream webservers {
                                           server 172.16.100.6:80 weight=1;
                                           server 172.16.100.69:80 weight=1;
                       }

                     location   /   {

                                           proxy_pass   http://websrvers/;

                     }

# nginx   -t  

# systemctl start nginx.service
# netstat -tnlp
用浏览器访问172.16.100.67
# scp nginx.conf node2:/etc/nginx/

节2
# systemctl start nginx.service
# netstat -tnlp

用浏览器访问172.16.100.68看能否负载均衡

• 用keepalived监控nginx服务

节1&节2
# vim keepalived.conf 
     vrrp_script chk_nginx {
             script "killall -0 nginx &> /dev/null"
             interval 1 
             weight -10
       }
       vrrp_instance VI_1 {
             track_script {
                   chk_nginx
             }
       }
节1

# systemctl status nginx.service

# systemctl start keepalived.service ssh node2:systemctl start keepalived.service

# systemctl status keepalived.service

# ip addr list

如果没启动起来，可能是组播地址和虚拟地址的问题，修改一下即可

宕掉nginx，肯是否会转到节点2上

# systemctl stop nginx.service

# systemctl status nginx

节2

# ip addr list

节1

# systemctl start nginx.service

浏览器访问172.16.100.88

节1（主节点）只要在线，节2（备节点）就抢不走，除非节1宕掉
# vim notify

 #!/bin/bash

 #


 vip=172.16.100.88

 contact='root@localhost' 


 notify() {

 mailsubject="`hostname` to be $1: $vip floating"    

 mailbody="`date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"   

echo $mailbody | mail -s "$mailsubject" $contact

 }


 case "$1" in

           master)

              notify master
              systemctl restart nginx.service

              exit 0

           ;;

           backup)

               notify backup
               systemctl restart nginx.service

               exit 0

           ;;

           fault)

               notify fault

                exit 0

           ;;

           *)

               echo 'Usage: `basename $0` {master|backup|fault}'

               exit 1

            ;;

  esac

# scp notify.sh node2:/etc/keepalived/

# systemctl status keepalived

# ip addr list

主停掉，备也停掉，会自动启动nginx

# systemctl stop httpd.server

节2

# systemctl stop nginx.service

# systemctl status keepalived

节1

# systemctl status nginx.service

# systemctl status keepalived

双主模型

节1
# vim keepalived.conf
            vrrp_instance VI_2 {

                        state BACKUP

                        interface ens33

                        virtual_router_id 61

                        priority 99

                        advert_int 1

                        authentication {

                                 auth_type PASS

                                 auth_pass 1111

                       }

                       virtual_ipaddress {

                                172.16.100.180/16 dev ens33 label ens33:2

                       }

                       track_script {

                                      chk_nginx

                       }

                        notify_master “/etc/keepalived/notify.sh master”   (不手动启动nginx，而让监控系统确保nginx在线）

                        notify_backup “/etc/keepalived/notify.sh backup”

                        notify_fault “/etc/keepalived/notify.sh fault”

             }
节1&节2
(不手动启动nginx，而让监控系统确保nginx在线）
# vim notify.sh
   注释掉systemctl restart nginx.service
节2
# vim keepalived.conf

        vrrp_instance VI_2 {

                        state MASTER

                        interface ens33

                        virtual_router_id 61

                        priority 100

                        advert_int 1

                        authentication {

                                 auth_type PASS

                                 auth_pass 1111

                       }

                       virtual_ipaddress {

                                172.16.100.180/16 dev ens33 label ens33:2

                       }

                       track_script {

                                      chk_nginx
                       }

                       notify_master “/etc/keepalived/notify.sh master” 

                       notify_backup “/etc/keepalived/notify.sh backup”

                       notify_fault “/etc/keepalived/notify.sh fault”

         }
节1

# sytemctl restart keepalived.service; ssh node2'sytemctl restart keepalived.service'
# systemctl status keepalived
# ifconfig ens33:1 down
# sytemctl restart keepalived.service; ssh node2'sytemctl restart keepalived.service'
# systemctl status keepalived

节2
# systemctl status keepalived.service
# ip addr list
用浏览器访问两个地址，看调度是否有问题
节1

# sytemctl restart keepalived.service; sytemctl start httpd.service
# systemctl status keepalived


节2
# ifconfig
节1
# sytemctl stop httpd.service; sytemctl restart nginx.service'
# systemctl status nginx.service

# systemctl status keepalived

# ifconfig