1. Keepalived-部署与基本概念

Keepalived部署与基本概念

1.Keepalived高可用概念

1.什么是高可用

什么是高可用双击热备，一般指两台机器启动这相同业务系统当有一台机器down机了，另外一台服务器迅速的接管，对于访问的用户是无感知的。

2.高可用使用场景

那么高可用是用在什么场景，业务系统需要保证7x24小时不DOWN机状态，作为业务来说随时都可用，让你的业务系统更顽强。

3.高可用VRRP原理

• 将所有设备加入到一个虚拟组

• 具有相同的虚拟ip（会有对应的虚拟MAC）

• 主机会在发送数据的时候，在数据包的目标地址协商虚拟的ip及MAC

• 虚拟主机收到数据后，会将目标地址转换成当前虚拟组的master设备ip和MAC

  角色：一主多备

  实际工作角色：主

  通过优先级来选举主备：越高越优先

环境

2.keepalived服务安装（二选一）

2.1 yum方式安装方式

[root@lb01 ~]# curl -o  /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
[root@lb01 ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
yum -y install keepalived

#配置文件
[root@lb01 ~]# rpm -qc keepalived
/etc/keepalived/keepalived.conf
/etc/sysconfig/keepalived

2.2 编译安装方式

[root@lb01 ~]# curl -o  /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
[root@lb01 ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
#安装依赖包
[root@lb01 ~]# yum install gcc openssl-devel libnl3-devel libnfnetlink-devel
[root@lb01 ~]# mkdir tools
[root@lb01 ~]# cd tools

[root@lb01 tools]# wget -c http://www.keepalived.org/software/keepalived-1.4.4.tar.gz
[root@lb01 tools]# tar -zxvf keepalived-1.4.4.tar.gz -C /usr/local
[root@lb01 tools]# cd keepalived-1.4.4/
[root@lb01 keepalived-1.4.4]# ./configure --prefix=/usr/local/keepalived
make && make install 

#配置文件
/usr/local/keepalived/etc/keepalived

#启动
systemctl start keepalived

3. 修改keepalived主配置文件

​lb01操作​

[root@lb01 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
    router_id master
}
#关联检测脚本
vrrp_instance VI_1 {
   state MASTER
   interface ens32
   virtual_router_id 51
   priority 100
   advert_int 1

  authentication {
       auth_type shecc
       auth_pass shecc123
   }
   virtual_ipaddress {
       10.1.33.185
   }
}

[root@lb01 ~]# systemctl enable keepalived
[root@lb01 ~]# systemctl start keepalived

​lb02操作​

[root@lb02 ~]# vim /etc/keepalived/keepalived.conf 
! Configuration File for keepalived

global_defs {
  router_id backup
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens32
    virtual_router_id 51
    priority 80
    advert_int 1
   
   authentication {
       auth_type shecc
       auth_pass shecc123
   }
   virtual_ipaddress {
     10.1.33.185
   }
}

[root@lb02 ~]# systemctl enable keepalived
[root@lb02 ~]# systemctl start keepalived

​验证​ 说明：VIP地址正常会漂移到高优先级LB01主机 当LB01主机宕机后才会飘逸到LB02中；通过长ping或使用ip add show ens32命令来判断LB01宕机后地址是否会飘逸到LB02中，LB01恢复后VIP地址会飘逸到LB01中，从而实现高可用。
命令行输入ip add show ens32进行VIP地址查看

长ping过程中模拟LB01宕机 关闭LB01keepalived服务即可，成功漂移到LB02后。我们再模拟LB01恢复 ，重新开启keepalived服务。

​图片说明​ 红框为关闭LB01 keepalived服务VIP漂移到LB02会出现延迟或者丢一个包这都属于正常现象。
黄框为恢复LB01keepalived服务后地址会飘逸到LB01会现延迟或者丢一个包这都属于正常现象。

完成