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linux集群-高可用集群

O：环境配置

Ⅰ：安装keepalived

两节点配置yum源

cd /etc/yum.repos.d
rm -f C*
cat local.repo

[gpmall]
name=gpmall
baseurl=file:///opt/gpmall-repo
gpgcheck=0
enabled=1

yum clean all
yum repolist

安装

yum install -y keepalived

配置文件

 cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {         #全局配置标识，表明这个区域{}是全局配置
   notification_email {    
        131917381@qq.com   #表示发送通知邮件时邮件源地址是谁
   }
   notification_email_from root@aaaaa.com    #表示keepalived在发生诸如切换操作时需要发送email通知，以及email发送给哪些邮件地址，邮件地址可以多个，每行一个
   smtp_server 127.0.0.1      #表示发送email时使用的smtp服务器地址，这里可以用本地的sendmail来实现
   smtp_connect_timeout 30    #连接smtp连接超时时间
   router_id LVS_DEVEL      #机器标识
}

vrrp_script chk_nginx {    
    script "/usr/local/sbin/check_ng.sh"    #检查服务是否正常，通过写脚本实现，脚本检查服务健康状态
    interval 3    #检查时间间断是3秒
    }

vrrp_instance VI_1 {        #VRRP配置标识 VI_1是实例名称
    state MASTER        #定义master相关
    interface ens33    #通过vrrp协议去通信、去发广播。此为网卡名
    virtual_router_id 51   #定义路由器ID ，配置的时候和从机器一致    
    priority 100   #权重，主角色和从角色的权重是不同的，一般主比从大
    advert_int 1  #设定MASTER与BACKUP主机质检同步检查的时间间隔，单位为秒
    authentication {        #认证相关信息
        auth_type PASS      #认证类i
        auth_pass 5201314>g     #密码的形式是一个字符串
    }
    virtual_ipaddress {     #设置虚拟IP地址 (VIP),又叫做漂移IP地址
        192.168.200.100
    }
    track_script {       #加载脚本
        chk_nginx
    }
}

编辑脚本并给予权限

cat /usr/local/sbin/check_ng.sh
#!/bin/bash                                     
  #时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量  
  n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量    
  if [ $n -eq "0" ]; then      
         /etc/init.d/nginx start
          n2=`ps -C nginx --no-heading|wc -l`   
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
          if [ $n2 -eq "0"  ]; then
                  echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
                  systemctl stop keepalived
          fi
 fi
 

chmod a+x /usr/local/sbin/check_ng.sh

Backup

 yum install -y epel-release     
 yum install -y nginx
 systemctl start keepalived

验证

curl -I 192.168.200.146
HTTP/1.1 200 OK
Server: nginx/1.20.1
Date: Mon, 19 Sep 2022 07:34:29 GMT
Content-Type: text/html
Content-Length: 4833
Last-Modified: Fri, 16 May 2014 15:12:48 GMT
Connection: keep-alive
ETag: "53762af0-12e1"
Accept-Ranges: bytes

curl -I 192.168.200.145
HTTP/1.1 200 OK
Server: nginx/1.20.1
Date: Mon, 19 Sep 2022 07:34:53 GMT
Content-Type: text/html
Content-Length: 4833
Last-Modified: Fri, 16 May 2014 15:12:48 GMT
Connection: keep-alive
ETag: "53762af0-12e1"
Accept-Ranges: bytes

 curl -I 192.168.200.100
HTTP/1.1 200 OK
Server: nginx/1.20.1
Date: Mon, 19 Sep 2022 07:35:04 GMT
Content-Type: text/html
Content-Length: 4833
Last-Modified: Fri, 16 May 2014 15:12:48 GMT
Connection: keep-alive
ETag: "53762af0-12e1"
Accept-Ranges: bytes

测试脚本


systemctl stop nginx
netstat -nltp |grep nginx
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      17655/nginx: master
tcp6       0      0 :::80                   :::*                    LISTEN      17655/nginx: master

给与权限，开启keepalived，查看ip

chmod a+x /usr/local/sbin/check_ng.sh   
[root@master ~]# systemctl start keepalived
ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:c4:90:9b brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.146/24 brd 192.168.200.255 scope global noprefixroute dynamic ens33
       valid_lft 1652sec preferred_lft 1652sec
    inet 192.168.200.100/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::14f3:d1b4:207a:b91/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

ps -aux |grep nginx
root       2071  0.0  0.0  39304   932 ?        Ss   15:20   0:00 nginx: master process /usr/sbin/nginx
nginx      2072  0.0  0.1  39692  1892 ?        S    15:20   0:00 nginx: worker process
nginx      2073  0.0  0.1  39692  1892 ?        S    15:20   0:00 nginx: worker process
root       2082  0.0  0.0 112720   984 pts/0    S+   15:20   0:00 grep --color=auto nginx