网关高可用之keepavlived全流程（安装/配置/验证/解析）

1.场景描述

因为要做网关的高可用，用到了keepalived+nginx，来保证nginx的高可用。（微服务时代之网关及注册中心高可用架构设计），如下图：

安装了keepavlived，走了一些弯路，记录下吧，nginx的安装就不多说了，自己博客已经介绍了好几篇了。

2. 解决方案

2.1 安装keepalived

2.1.1 安装相关依赖包

[root@t-ruanjianlaowang ~]# yum install -y libnl*
[root@t-ruanjianlaowang ~]#  yum install -y libnfnetlink-devel zlib zlib-devel gcc gcc-c++ openssl openssl-devel openssh

假如连不了，网上也有这些包的下载，下载后tar解压也行。

2.1.2 下载并安装keepalived

官网地址：https://www.keepalived.org/download.html

我们使用的最新版本：keepalived-2.0.18.tar.gz，993k

tar -zxvf keepalived-2.0.18.tar.gz
cd keepalived-2.0.18/
./configure --prefix=/usr/local/keepalived
make
make install

2.1.3 添加keepavlived为系统服务

[root@t-ruanjianlaowang ~]#  cp /usr/local/keepalived/etc/sysconfig/keepalived  /etc/sysconfig/keepalived 

[root@t-ruanjianlaowang ~]#  cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived

[root@t-ruanjianlaowang ~]# cp /root/tools/keepalived-2.0.18/keepalived/etc/init.d/keepalived   /etc/init.d/keepalived

#/etc/keepalived下好像有了keepalived文件夹，有了就不用mkdir了，软件老王
[root@t-ruanjianlaowang ~]# mkdir /etc/keepalived  
[root@t-ruanjianlaowang ~]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf

2.1.4 设置开机启动

# 设置开机启动
[root@t-ruanjianlaowang ~]# chkconfig keepalived on

[root@t-ruanjianlaowang ~]# service keepalived start|stop|restart

到这里仅仅是keepalived安装完成，接下来还要根据项目项目配置keepalived.conf信息。

2.2 配置文件修改

2.2.1 master的conf配置文件

vi cd /etc/keepalived/keepalived.conf

!Configuration File for keepalived
global_defs {
   router_id RUANJIANLAOWANG_MASTER
}

vrrp_script chk_nginx {
script "/etc/keepalived/nginx_check.sh"
interval 2
weight -20
}

vrrp_instance VI_1 {
state MASTER
interface ens666    #这里必须非常注意，软件老王刚开始没太注意，这里是你的网卡名称
virtual_router_id 81  #这个会在backup机器上用到
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}

track_script {
chk_nginx
}
virtual_ipaddress {
10.192.168.21
}
}

2.2.2 还有个检查nginx是否挂掉的sh，也上传下

vi nginx_check.sh 

#!/bin/bash
counter=$(ps -C nginx --no-heading|wc -l)
if [ "${counter}" = "0" ]; then
    /usr/sbin/nginx
    sleep 2
    counter=$(ps -C nginx --no-heading|wc -l)
    if [ "${counter}" = "0" ]; then
        /etc/init.d/keepalived stop
    fi
fi

2.2.3 backup机器上conf文件

/bin/bash: Configuration: command not found
bal_defs {
 router_id RUANJIANLAOWANG2
}
vrrp_script chk_nginx {
script "/etc/keepalived/nginx_check.sh" ## 检测 nginx 状态的脚本路径
interval 2 ## 检测时间间隔
weight -20 ## 如果条件成立，权重-20
}

vrrp_instance VI_1 {
state BACKUP
interface ens168
virtual_router_id 81

priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 111track_script {
           chk_nginx ## 执行 Nginx 监控的服务，软件老王
 }
virtual_ipaddress {
10.192.168.21
    }
}

这里记着也把检查nginx的sh文件上传上，跟master上的一样。

2.3 启动

（1）配置完成后开始启动

[root@t-ruanjianlaowang ~]# service keepalived start

（2）启动过程中，打开日志看一下（刚开始可能会有问题，看下日志啥都明白了）

[root@t-ruanjianlaowang ~]# tail -f  /var/log/messages

（3）假如启动不了，可以尝试以下方式。

[root@t-ruanjianlaowang ~]# systemctl daemon-reload

#上面试过后，不行再重新注册服务
[root@t-ruanjianlaowang ~]#chkconfig --del keepalived
[root@t-ruanjianlaowang ~]# cd /usr/lib/systemd/system/
[root@t-ruanjianlaowang ~]#rm -rf keepalived.service
[root@t-ruanjianlaowang ~]# chkconfig --add keepalived

2.4 验证

[root@t-ruanjianlaowang ~]#ip addr show ens666
[root@t-ruanjianlaowang ~]#ip addr show ens168
ens666、ens168为网卡名称

假如绑定成功，软件老王机器里显示的信息里面会有：10.192.168.21的显示

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