• 1. Keepalived的安装
    • 1.1. yum install方式
    • 1.2. 安装包编译方式
  • 2. 常用配置
    • 2.1. MASTER（主机配置）
    • 2.2. BACKUP（备机配置）
  • 3. 注意事项
  • 4. 常用脚本
    • 4.1. Nginx健康检测脚本
      • 4.1.1. 检查接口调用是否为200
      • 4.1.2. 检查Nginx进程是否运行
    • 4.2. Keepalived状态通知脚本

    1. Keepalived的安装

    1.1. yum install方式

    1. yum install -y keepalived

    1.2. 安装包编译方式

    更多安装包参考：http://www.keepalived.org/download.html

    1. wget http://www.keepalived.org/software/keepalived-2.0.7.tar.gz
    2. tar zxvf keepalived-2.0.7.tar.gz
    3. cd keepalived-2.0.7
    4. ./configure --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --mandir=/usr/share
    5. make && make install

    2. 常用配置

    keepalived配置文件路径：/etc/keepalived/keepalived。

    2.1. MASTER（主机配置）

    1. global_defs {
    2.     router_id proxy-keepalived
    3. }
    5. vrrp_script check_nginx {
    6.     script "/etc/keepalived/scripts/check_nginx.sh" 
    7.     interval 3  
    8.     weight 2   
    9. }
    11. vrrp_instance VI_1 {
    12.     state BACKUP
    13.     interface eth2
    14.     virtual_router_id 15
    15.     priority 100
    16.     advert_int 1
    17.     authentication {
    18.         auth_type PASS
    19.         auth_pass xxx
    20.     }
    21.     track_script {
    22.         check_nginx 
    23.     }
    24.     virtual_ipaddress {
    25.         180.101.115.139
    26.         218.98.38.29
    27.     }
    29.     nopreempt
    31.     notify_master "/etc/keepalived/keepalived_notify.sh master"
    32.     notify_backup "/etc/keepalived/keepalived_notify.sh backup"
    33.     notify_fault "/etc/keepalived/keepalived_notify.sh fault"
    34.     notify_stop "/etc/keepalived/keepalived_notify.sh stop"
    35. }

    2.2. BACKUP（备机配置）

    1. global_defs {
    2.     router_id proxy-keepalived
    3. }
    5. vrrp_script check_nginx {
    6.     script "/etc/keepalived/scripts/check_nginx.sh" 
    7.     interval 3  
    8.     weight 2   
    9. }
    11. vrrp_instance VI_1 {
    12.     state BACKUP 
    13.     interface eth2
    14.     virtual_router_id 15
    15.     priority 99
    16.     advert_int 1
    17.     authentication {
    18.         auth_type PASS
    19.         auth_pass xxx
    20.     }
    21.     track_script {
    22.         check_nginx 
    23.     }
    24.     virtual_ipaddress {
    25.         180.101.115.139
    26.         218.98.38.29
    27.     }
    29.     nopreempt
    31.     notify_master "/etc/keepalived/keepalived_notify.sh master"
    32.     notify_backup "/etc/keepalived/keepalived_notify.sh backup"
    33.     notify_fault "/etc/keepalived/keepalived_notify.sh fault"
    34.     notify_stop "/etc/keepalived/keepalived_notify.sh stop"
    35. }

    3. 注意事项

    1、指定Nginx健康检测脚本：/etc/keepalived/scripts/check_nginx.sh

    2、主备配置差别主要为（建议这么配置）：

    以下两种方式的配置，当其中一台机器keepalived挂掉后会自动VIP切到另一台机器，当挂掉机器keepalived恢复后不会抢占VIP，该方式可以避免机器恢复再次切VIP所带来的影响。

    • 主机:(state BACKUP;priority 100)
    • 备机：(state BACKUP;priority 99)

    • 非抢占：nopreempt

      或者：

    • 主机:(state MASTER;priority 100)

    • 备机：(state BACKUP;priority 100)
    • 默认抢占

    3、指定VIP

    1.     virtual_ipaddress {
    2.         180.101.115.139
    3.         218.98.38.29
    4.     }

    4、可以指定为非抢占：nopreempt，即priority高不会抢占已经绑定VIP的机器。

    5、制定绑定IP的网卡： interface eth2

    6、可以指定keepalived状态变化通知

    1.     notify_master "/etc/keepalived/keepalived_notify.sh master"
    2.     notify_backup "/etc/keepalived/keepalived_notify.sh backup"
    3.     notify_fault "/etc/keepalived/keepalived_notify.sh fault"
    4.     notify_stop "/etc/keepalived/keepalived_notify.sh stop"

    7、virtual_router_id 15值，主备值一致，但建议不应与集群中其他Nginx机器上的相同，如果同一个网段配置的virtual_router_id 重复则会报错，选择一个不重复的0~255之间的值，可以用以下命令查看已存在的vrid。

    1. tcpdump -nn -i any net 224.0.0.0/8

    4. 常用脚本

    4.1. Nginx健康检测脚本

    在Nginx配置目录下（/etc/nginx/conf.d/）增加health.conf的配置文件,该配置文件用于配置Nginx health的接口。

    1. server {
    2.     listen       80  default_server;
    3.     server_name  localhost;
    4.     default_type text/html;
    5.     return 200 'Health';  
    6. }

    Nginx健康检测脚本：/etc/keepalived/scripts/check_nginx.sh

    4.1.1. 检查接口调用是否为200

    1. #!/bin/sh
    2. set -x
    4. timeout=30 #指定默认30秒没返回200则为非健康，该值可根据实际调整
    6. if [ -n ${timeout} ];then
    7.     httpcode=`curl -sL -w %{http_code} -m ${timeout} http://localhost -o /dev/null`
    8. else
    9.     httpcode=`curl -sL -w %{http_code}  http://localhost -o /dev/null`
    10. fi
    12. if [ ${httpcode} -ne 200 ];then
    13.         echo `date`':  nginx is not healthy, return http_code is '${httpcode} >> /etc/keeperalived/keepalived.log
    14.         killall keepalived
    15.         exit 1
    16. else
    17.         exit 0
    18. fi

    4.1.2. 检查Nginx进程是否运行

    1. #!/bin/sh
    2. if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
    3.         echo "$(date) nginx pid not found">>/etc/keepalived/keepalived.log
    4.         killall keepalived
    5. fi

    4.2. Keepalived状态通知脚本

    1. #!/bin/bash
    2. set -x
    4. warn_receiver=$1
    5. ip=$(ifconfig bond0|grep inet |awk '{print $2}')
    6. warningInfo="${ip}_keepalived_changed_status_to_$1"
    7. warn-report --user admin --key=xxxx --target=${warn_receiver} ${warningInfo}
    8. echo $(date)  $1 >> /etc/keepalived/status

    说明：

    1. ip获取本机IP，本例中IP获取是bond0的IP，不同机器网卡名称不同需要修改为对应网卡名称。
    2. 告警工具根据自己指定。