集群介绍keepalived介绍用keepalived配置高可用集群

Posted 2021-01-04

集群介绍

keepalived介绍

用keepalived配置高可用集群

keepalived他需要包含一个服务，比如这个服务用来实现高可用，最早讲述集群的时候一个角色可能存在单点故障，如果这个服务当机就有问题了，现在想让这个服务高可用就得用一个keepalived或者heartbeat等高可用的软件，让他实现高可用
搭建了高可用的集群首先要有个keepalived的服务然后还要有让那个服务去实现高可用，这里用nginx做高可用的实验
为什么用nginx做实验对象，因为在工作中或在生产环境中好多企业把nginx作为负载均衡器，后面讲负载均衡集群的时候会介绍到nginx他可以实现负载均衡

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准备两台机器192.168.63.100和192.168.63.101，192.168.63.100作master，192.168.63.101作为backup
两台机器都执行yum install -y keepalived

两台机器都安装nginx，其中100上已经编译安装过nginx，101上需要yum安装nginx: yum install -y nginx

在101上安装nginx的时候提示没有可用软件包 nginx。错误：无须任何处理，这个因为centos7系统库中默认是没有nginx的rpm包的，所以我们自己需要先更新下rpm依赖库

[[email protected] ~]# rpm -Uvh http://nginx.org/packages/centos/7/noarch/RPMS/nginx-release-centos-7-0.el7.ngx.noarch.rpm             ##更新rpm依赖库

以上操作完成后修改100上keepalived的配置文件，配置文件内容去https://coding.net/u/aminglinux/p/aminglinux-book/git/blob/master/D21Z/master_keepalived.conf获取

[[email protected] ~]# ls /etc/keepalived/keepalived.conf      ##配置文件路径
/etc/keepalived/keepalived.conf

[[email protected] ~]# > !$                        ##清空配置文件的原始内容
> /etc/keepalived/keepalived.conf

[[email protected] ~]# vim /etc/keepalived/keepalived.conf        ##进入配置文件编辑，把以下内容拷贝到这个配置文件里

global_defs {
   notification_email {
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_nginx {
    script "/usr/local/sbin/check_ng.sh"
    interval 3
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass aminglinux>com
    }
    virtual_ipaddress {
        192.168.188.100
    }

    track_script {
        chk_nginx
    }

}

130上定义检查nginx是否正常的脚本，内容从https://coding.net/u/aminglinux/p/aminglinux-book/git/blob/master/D21Z/master_check_ng.sh获取

[[email protected] ~]# vim /usr/local/sbin/check_ng.sh        ##写入以下内容

#!/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，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
        /etc/init.d/nginx start
        n2=`ps -C nginx --no-heading|wc -l`
        if [ $n2 -eq "0"  ]; then
                echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
                systemctl stop keepalived
        fi
fi

写完脚本做权限如果不去改这个他就没有权限自动加载这个脚本

[[email protected] ~]# chmod 755 /usr/local/sbin/check_ng.sh

100上启动服务

[[email protected] ~]# systemctl start keepalived

关闭nginx服务自动起来keep成功

查看日志

[[email protected] ~]# less /var/log/messages

开始配置从，在配置从之前先看防火墙

从上修改配置文件内容从https://coding.net/u/aminglinux/p/aminglinux-book/git/blob/master/D21Z/backup_keepalived.conf获取

[[email protected] ~]# vim /etc/keepalived/keepalived.conf     ##写入一下内容

global_defs {
   notification_email {
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_nginx {
    script "/usr/local/sbin/check_ng.sh"
    interval 3
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass aminglinux>com
    }
    virtual_ipaddress {
        192.168.188.100
    }

    track_script {
        chk_nginx
    }

}

定义检查nginx是否正常的脚本内容从https://coding.net/u/aminglinux/p/aminglinux-book/git/blob/master/D21Z/backup_check_ng.sh获取

[[email protected] ~]# vim /usr/local/sbin/check_ng.sh        ##写入以下内容

#!/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，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
        systemctl start nginx
        n2=`ps -C nginx --no-heading|wc -l`
        if [ $n2 -eq "0"  ]; then
                echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
                systemctl stop keepalived
        fi
fi

给脚本755权限

[[email protected] ~]# chmod 755 /usr/local/sbin/check_ng.sh

启动keepalived服务

[[email protected] ~]# systemctl start keepalived

删除nginx自动启动成功

区分主从的nginx

主默认页

从，是yum安装的默认页

访问63.200的默认页

下面做测试高可用的时候访问的是vip的ip是192.168.63.200

停掉Keepalived查看是否高可用成功

以前主没事的时候vip显示主的页面，主出现问题后跳转到从的页面设置高可用设置成功

主上恢复后，从上不运行vip的ip了一切恢复正常

高可用集群测试完毕