keepalived高可用集群服务

一、简介

keepalived 是专门用来监控LVS集群系统中各个节点的状态，后来又加入了VRRP(虚拟路由器冗余协议)功能

二、keepalived的两大功能

1、对节点做健康检查  healthcheck
2、高可用对之间的失败接管（接管的有VIP资源及相应的服务） failover

三、keepalived工作原理

1、VRRP(虚拟路由器冗余协议)，它的出现就是为了解决静态路由的单点故障。
2、VRRP是通过一种竞选协议机制来将路由任务交给某台VRRP路由器。
3、VRRP通信是通过IP多播的方式实现通信。
4、主发包，备接收包。备接不到包的时候，接管主的资源。备可以有多个，通过优先级竞选
5、VRRP使用了加密协议，如果是web服务的接管，可以接管的快一点，1~2秒即可。

四、keepalived安装布署

#下载并安装
[root@linux-node1 ~]# yum -y install libnl*  popt*           #安装依赖包
[root@linux-node1 ~]# cd /usr/local/src/
[root@linux-node1 src]# wget http://www.keepalived.org/software/keepalived-1.2.2.tar.gz
[root@linux-node1 src]# tar -xf keepalived-1.2.2.tar.gz 
[root@linux-node1 src]# cd keepalived-1.2.2
[root@linux-node1 keepalived-1.2.2]# ./configure 
[root@linux-node1 keepalived-1.2.2]# make && make install

#拷贝配置文件
[root@linux-node1 ~]# cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/ 

#启动脚本
[root@linux-node1 ~]# cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/ 

#配置启动脚本参数
[root@linux-node1 ~]# mkdir -p /etc/keepalived

#创建配置文件目录
[root@linux-node1 ~]# cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

#配置文件模板
[root@linux-node1 ~]# cp /usr/local/sbin/keepalived /usr/sbin/

#启动服务
[root@linux-node1 ~]# /etc/init.d/keepalived start
Reloading systemd:                                         [  OK  ]
Starting keepalived (via systemctl):                       [  OK  ]

[root@linux-node1 ~]# ps -ef | grep keepalived
root       5072      1  0 14:15 ?        00:00:00 keepalived -D
root       5074   5072  0 14:15 ?        00:00:00 keepalived -D
root       5076   1724  0 14:15 pts/0    00:00:00 grep --color=auto keepalived

备注：另一台安装方式完全一样

五、配置keepalived单实例

#主负载均衡器配置如下
[root@linux-node1 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
   notification_email {
   [e-mail]
   }
   smtp_server 192.168.23.1
   smtp_connect_timeout 30
   router_id LVS_7
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 7
    priority 150
    advert_int 1
    authentication {
    auth_type PASS
    auth_pass 1111
    }
    virtual_ipaddress {
        192.168.23.100/24
    }
}


#备负载均衡器配置
[root@linux-node2 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
   notification_email {
   [e-mail]
   }
   smtp_server 192.168.23.1
   smtp_connect_timeout 30
   router_id LVS_8
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 7
    priority 100
    advert_int 1
    authentication {
    auth_type PASS
    auth_pass 1111
    }
    virtual_ipaddress {
        192.168.23.100/24
    }
}

---

扩展：配置文件说明

global_defs {              #全局定义
   notification_email {    #通知的email，可以不配
   [e-mail]           #收件人是谁，可以不配
   }
   notification_email_from [e-mail]   #发件人是谁，可以不配
   smtp_server 192.168.23.1      #发邮件服务器，可以不配
   smtp_connect_timeout 30       #超时，可以不配
   router_id LVS_7               #keepalive的id，不同机器不一样
}

vrrp_instance VI_1 {            #实例名
    state MASTER                #状态，标记路由器的状态
    interface eth0              #提供服务端口或绑定vip的端口
    virtual_router_id 55        #虚拟路由ID,主备必须一样
    priority 150                #优先级，判断主备机，以这个为主
    advert_int 1                #高可用对之间接管的间隔
    authentication {
        auth_type PASS          #认证的类型
        auth_pass 1111          #认证密码
    }
    virtual_ipaddress {
        192.168.23.100/24           #提供服务的VIP
    }
}

六、重启服务并测试

#先启动主node1，后启动备机node2
[root@linux-node1 ~]# /etc/init.d/keepalived restart

#检查主备负载均衡器VIP情况
[root@linux-node1 ~]# ip add | grep 192.168.23.100
    inet 192.168.23.100/24 scope global secondary ens33

[root@linux-node2 ~]# ip add | grep 192.168.23.100
备服务器上没有出现VIP表明配置正确

七、指定文件接收日志

1、在全局配置文件中追加
echo KEEPALIVED_OPTIONS="-D -d -S 0" >> /etc/sysconfig/keepalived

2、在日志配置文件中追加
echo "local0.*   /var/log/keeplived.log" >> /etc/rsyslog.conf

3、重启服务(日志服务和keepalived服务)