Nginx高可用 - Keepalived安装部署

1.安装依赖以及Keepalived

安装Keepalived依赖

yum install curl gcc autoconf automake openssl-devel libnl3-devel    iptables-devel ipset-devel net-snmp-devel libnfnetlink-devel file-devel aclocal autoheader autoreconf -y
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安装Keepalived

# 下载Keepalived
curl -O --progress https://www.keepalived.org/software/keepalived-2.2.7.tar.gz
# 解压
tar -xvf keepalived-2.2.7.tar.gz
# 安装
cd keepalived-2.2.7/
# 指定安装目录/usr/local/keepalived
./configure --prefix=/usr/local/keepalived
make & make install
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配置环境

Keepalived 启动脚本变量引用文件，默认文件路径是 /etc/sysconfig/，也可以不做软链接，直接修改启动脚本中文件路径即可
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/keepalived

# 将keepalived 主程序加入到环境变量
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived

# keepalived 启动脚本（源码目录下），放到 /etc/init.d/ 目录下就可以使用 service 命令便捷调用
cp /etc/keepalived/keepalived-2.2.7/keepalived/etc/init.d/keepalived  /etc/init.d/keepalived

# 将配置文件放到默认路径下 (可以在/etc/init.d/keepalived中修改默认路径)
mkdir /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf.sample /etc/keepalived/keepalived.conf
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2. 修改配置

# 修改keepalived.conf配置
vim /etc/keepalived/keepalived.conf
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keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     xxx@xx.com
   }
   notification_email_from xx@xx.com
   smtp_server smtp.sohu.com
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script check_nginx {
   script "/etc/keepalived/nginx_check.sh"
   interval 2
   weight 2
   fall 1
}


vrrp_instance nginx_master {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 101
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    track_script {
	    check_nginx
    }
    virtual_ipaddress {
        192.168.10.213
    }
}

virtual_server 192.168.200.100 443 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.201.100 443 {
        weight 1
        SSL_GET {
            url {
              path /
              digest ff20ad2481f97b1754ef3e12ecd3a9cc
            }
            url {
              path /mrtg/
              digest 9b3a0c85a887a256d6939da88aabd8cd
            }
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }
}

virtual_server 10.10.10.2 1358 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    sorry_server 192.168.200.200 1358

    real_server 192.168.200.2 1358 {
        weight 1
        HTTP_GET {
            url {
              path /testurl/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl3/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.200.3 1358 {
        weight 1
        HTTP_GET {
            url {
              path /testurl/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334c
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }
}

virtual_server 10.10.10.3 1358 {
    delay_loop 3
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.200.4 1358 {
        weight 1
        HTTP_GET {
            url {
              path /testurl/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl3/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.200.5 1358 {
        weight 1
        HTTP_GET {
            url {
              path /testurl/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl3/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }
}
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配置详解

• global_defs =>
  notification_email 故障发生时给谁发邮件通知
  notification_email_from 通知邮件从哪个地址发出
  smtp_server 通知邮件的smtp地址
  smtp_connect_timeout 连接smtp服务器的超时时间
  enable_traps开启SNMP（Simple Network Management Protocol）陷阱
  router_id 标志本节点的字符串，通常为ip地址，故障发生时邮件会通知到

• vrrp_script check_nginx =>
  check_nginx 自定义脚本名称
  script: 自己写的监测脚本。
  interval 2: 每2s监测一次
  weight -20：监测失败，则相应的vrrp_instance的优先级会减少20个点

• vrrp_instance nginx_master =>
  vrrp_instance 自定义节点名称
  state:只有BACKUP和MASTER。MASTER为工作状态，BACKUP是备用状态
  interface:为网卡接口：可通过ip addr查看自己的网卡接口
  virtual_router_id:虚拟路由标志。同组的virtual_router_id应该保持一致。它将决定多播的MAC地址
  priority：设置本节点的优先级，优先级高的为MASTER
  advert_int: MASTER与BACKUP同步检查的时间间隔
  virtual_ipaddress：虚拟IP

nginx_check.sh

#!/bin/bash
nginx_kp_check(){
nginxpid=`ps -C nginx --no-header |wc -l`
if [ $nginxpid -eq 0 ]; then
    /user/local/nginx/sbin/nginx
    sleep 1
    nginxpid=`ps -C nginx --no-header |wc -l`
    if [ $nginxpid -eq 0 ];then
        systemctl stop keepalived
    fi
fi
}
nginx_kp_check
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3. 修改Keepalived日志路径

默认在/var/log/messages中

 # 修改/usr/local/keepalived/etc/sysconfig/keepalived
 vim /usr/local/keepalived/etc/sysconfig/keepalived
 # 把KEEPALIVED_OPTIONS="-D" 修改为：KEEPALIVED_OPTIONS="-D -d -S 0"
 KEEPALIVED_OPTIONS="-D -d -S 0" 
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# 在/etc/rsyslog.conf 末尾追加
vim /etc/rsyslog.conf
local0.*                                                /var/log/keepalived.log
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4. 重启rsyslog

systemctl restart rsyslog
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5. 启动/重启Keepalived

service keepalived start
service keepalived restart
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6.查看日志

tail -f /var/log/keepalived.log
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7.查看Ip是否成功

ip a show |grep -w inet
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出现指定VIP则成功

注意:

从服务器记得修改 vrrp_instance.state 为 BACKUP

改 vrrp_instance.priority 比MASTER 低的值

测试结果

1. 当MASTER节点Nginx挂了时，会尝试再次启动Nginx，无法启动时，会自动切换到BACKUP节点上，当MASTER节点恢复时，自动从BACKUP节点恢复到MASTER节点。
2. 当所有节点都挂了时，哪个节点恢复了虚拟IP就指向哪个节点。

恢复时注意先启动Nginx再启动Keepalived