keepalived安装配置 (Centos7)

作者: 周末不加班 | 来源:发表于2019-01-08 18:04 被阅读0次

keepalived简介

keepalive是一款可以实现高可靠的软件，通常部署在2台服务器上，分为一主一备。Keepalived可以对本机上的进程进行检测，一旦Master(主)检测出某个进程出现问题，将自己切换成Backup(副)状态，然后通知另外一个节点切换成Master(主)状态。

下载、安装

Keepalived for Linux - [Version 2.0.10]
其他版本下载地址

# 将keepalived解压到/usr/local目录下
 tar -zxvf keepalived-2.0.11.tar.gz  -C /usr/local

# 进入到/usr/local/keepalived-2.0.11目录
cd /usr/local/keepalived-2.0.11

# 开始configure
./configure --prefix=/usr/local/keepalived

#编译并安装
make && make install

出现以下信息表示编译成功

Keepalived configuration
------------------------
Keepalived version       : 2.0.11
Compiler                 : gcc
Preprocessor flags       :  
Compiler flags           : -Wall -Wunused -Wstrict-prototypes -Wextra -Winit-self -g -D_GNU_SOURCE -fPIE -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -O2 
Linker flags             :  -pie
Extra Lib                :  -lcrypto  -lssl  -lnl
Use IPVS Framework       : Yes
IPVS use libnl           : Yes
IPVS syncd attributes    : No
IPVS 64 bit stats        : No
HTTP_GET regex support   : No
fwmark socket support    : Yes
Use VRRP Framework       : Yes
Use VRRP VMAC            : Yes
Use VRRP authentication  : Yes
With ip rules/routes     : Yes
Use BFD Framework        : No
SNMP vrrp support        : No
SNMP checker support     : No
SNMP RFCv2 support       : No
SNMP RFCv3 support       : No
DBUS support             : No
SHA1 support             : No
Use JSON output          : No
libnl version            : 1
Use IPv4 devconf         : No
Use iptables             : Yes
Use libiptc              : No
Use libipset             : No
Use nftables             : No
init type                : systemd
Strict config checks     : No
Build genhash            : Yes
Build documentation      : No

编译可能出现的问题

问题1:

*** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.

执行yum命令yum -y install libnl libnl-devel解决上述警告问题

yum -y install libnl libnl-devel

问题2：

configure: error: in `/usr/local/keepalived-2.0.11':
configure: error: no acceptable C compiler found in $PATH
See `config.log' for more details

缺少C编译器安装GCC软件套件 yum install gcc

yum install gcc

问题3

configure: error: 
  !!! OpenSSL is not properly installed on your system. !!!
  !!! Can not include OpenSSL headers files.            !!!
[root@dajia keepalived-2.0.11]#

yum -y install openssl-devel

安装完成以后，重新执行configure ... 命令

将keepalived添加到系统服务中

路径	说明
/usr/local/keepalived-2.0.10	解压后源码存放路径
/usr/local/keepalived	安装目录

# 拷贝执行文件
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

# 将初始化脚本拷贝到系统初始化目录下
cp /usr/local/keepalived-2.0.10/keepalived/etc/init.d/keepalived /etc/init.d/

# 将keepalived配置文件拷贝到etc下
cp /usr/local/keepalived-2.0.10/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

# 创建keepalived文件夹
mkdir /etc/keepalived/

# 将keepalived配置文件拷贝到etc下
cp /usr/local/keepalived-2.0.10/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

# 添加可执行权限
chmod +x /etc/init.d/keepalived

# 添加keepalived到开机启动
chkconfig --add keepalived
chkconfig keepalived on

此时已加入系统服务可使用services 启动

#启动
service keepalived start
#停止
service keepalived stop
#重启
service keepalived restart
#查看启动情况
ps -aux |grep keepalived

配置keepalived虚拟IP

修改刚添加到系统的配置文件：vi /etc/keepalived/keepalived.conf
注意是系统的配置文件(/etc/keepalived/keepalived.conf)
注意是系统的配置文件(/etc/keepalived/keepalived.conf)
注意是系统的配置文件(/etc/keepalived/keepalived.conf)
不是安装目录/usr/local...下的

因为这个问题我找的好辛苦！！！

找到虚拟路由节点 vrrp_instance（Virtual Router Redundancy Protocol）

vrrp_instance VI_1 {
    state MASTER          //MASTER主节点，备用节点上设置为state BACKUP
    interface ens33        //绑定虚拟机IP的网卡  两个节点设置一样 根据 ipaddr换成对应的网卡地址
    virtual_router_id 51  //VRRP组名，主副节点设置必须一样，指名各个节点属于同一个VRRP组，同一个组的节点互相抢IP
    priority 100         //优先级(1~254之间)，备用节点必须比主节点优先级低
    advert_int 1         //组播信息发送间隔，两个节点设置必须一样
    authentication {    //设置验证信息， 两个节点设置必须一样，用于节点间信息转发时的加密
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {  // 虚拟IP两个节点设置必须一样，两节点同时抢一个io
        192.168.33.60/24  // 如果两个nginx的ip分别是192.168.33.61,,...62，则此处的虚拟ip跟它俩同一个网段即可 24代表3个255的子网掩码
    }
}

如果要 ping 192.168.33.60 还需要注释掉配置文件中的# vrrp_strict

遇到的问题

主备都抢到了虚拟ip

采用tcpdump抓包定位问题，以下是在192.168.93.141 主节点的抓包结果
tcpdump -i ens33 vrrp -n

192.168.93.141主服务器

以下是在10.11.4.187 备节点的抓包结果
tcpdump -i ens33 vrrp -n

10.11.4.187备用服务器

由上图可以看到，192.168.93.140和192.168.93.141两个IP在轮流发送组播信号。而正常的应该是由MASTER服务器发送组播，如果BACKUP收不到MASTER的组播信号了，那么判定MASTER宕机了，BACKUP就会接手VIP

问题就是出现在了防火墙这里，防火墙阻止了vrrp组包发送

如果是Firewalld防火墙则主、备都运行下面的命令

[root@dajia sysconfig]# firewall-cmd --direct --permanent --add-rule ipv4 filter INPUT 0  --protocol vrrp -j ACCEPT
success
[root@dajia sysconfig]# firewall-cmd --reload
success

参考文章

配置Keepalived监听Nginx

修改系统的配置文件(vi /etc/keepalived/keepalived.conf)

添加Nginx心跳检测脚本 vrrp_script check_nginx_alive
在vrrp_instance VI_1中加入track_script 调用check_nginx_alive每隔1秒检查Nginx状态
在vrrp_instance VI_1中为keepalived 三个状态接口 notify_master , notify_backup, notify_fault添加脚本/usr/local/keepalived/sbin/notify.sh (当keepalived状态改变时调用相同脚本但传入不同参数)

vrrp_script check_nginx_alive {
    script "[[ `ps -ef | grep nginx | grep -v grep | wc -l` -ge 2 ]] && exit 0 || exit 1"
    interval 1    #每隔1秒执行上述的脚本，检查ngnix状态
    weight -2     #宕机一次将自身权重减2
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.93.180/24
    }

    # 新增检测Nginx脚本 自定义脚本名check_nginx_alive
    track_script {
        check_nginx_alive
    }

    # keepalived 三个接口，当状态改变时执行用户自定义脚本
    notify_master "/usr/local/keepalived/sbin/notify.sh master"
    notify_backup "/usr/local/keepalived/sbin/notify.sh backup"
    notify_fault "/usr/local/keepalived/sbin/notify.sh fault"
}

添加切换通知脚本
vi /usr/local/keepalived/sbin/notify.sh

#!/bin/bash

case "$1" in
    master)
        echo 'Usage:notify.sh {master}'
        /usr/mysoftware/nginx/sbin/nginx
        exit 0
    ;;
    backup)
        echo 'Usage:notify.sh {backup}'
        /usr/mysoftware/nginx/sbin/nginx -s stop
        /usr/mysoftware/nginx/sbin/nginx
        exit 0
    ;;
    fault)
        echo 'Usage:notify.sh {fault}'
        /usr/mysoftware/nginx/sbin/nginx -s stop
        exit 0
    ;;
    *)
        echo 'Usage:notify.sh {master|backup|fault}'
        exit 1
    ;;
esac

添加执行权限！！！
chmod +x /usr/local/keepalived/sbin/notify.sh

如果遇到nginx无法被脚本调用，可直接运行 /usr/local/keepalived/sbin/notify.sh master 查看是否有echo输出

在第主、备机器上添加notify.sh脚本
分别启动主、备keepalived (此时两台机器的Nginx也启动了 )
结束备Nginx 与主Keepalived，当备切换为主时会再次启动Nginx

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