Centos7部署LVS+keepalived高可用集群

简介

在生产工作中，后台的服务器并不可能永远都处于正常运行状态，若服务器发生宕机，为了不影响正在进行的业务以及给用户更好的体验，我们可以通过keepalived监控后台服务器运行情况，当有服务器发生故障时，会从把该服务器剔除出LVS转发策略；等到服务器恢复正常后，keepalived也会重新把该服务器加入LVS转发策略中

前期准备

准备三台centos7虚拟机,配置IP地址和hostname，同步时间，关闭防火墙和selinux，配置IP地址和hostname映射
在node2和node3中部署httpd服务并修改首页内容

hostname	ip	index.html
node1	192.168.29.143	--
node2	192.168.29.142	client2
node3	192.168.29.144	client1

配置LVS负载均衡策略
详情可参考:https://blog.51cto.com/14832653/2501128

[root@node1 ~]# yum install keepalived -y

修改配置文件

[root@node1 ~]# vi /etc/keepalived/keepalived.conf 
! Configuration File for keepalived

global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   #1.3+版本需要把此行注释掉才能PING通
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

#组建vrrp实例组
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    virtual_ipaddress {
    192.168.29.122
    }
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
}
#设定真实服务器地址
virtual_server 192.168.29.122 80 {
    delay_loop 3
    lb_algo rr
    lb_kind DR
    protocol TCP
    real_server 192.168.29.142 80 {
        weight 1
        HTTP_GET {
        #url检测
        url {
        #指定所要检测的页面所在位置
        path /index.html
        status_code 200
        }
        }
        #tcp检测
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }   
    }
    real_server 192.168.29.144 80 {
        weight 1
        HTTP_GET {
        url {
        path /index.html
        status_code 200
        }
        }
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }   
    }
}

#启动keepalived服务
[root@node1 ~]# systemctl start keepalived.service 

测试验证

关闭node2的httpd服务

[root@node2 ~]# systemctl stop httpd.service 

一直刷新不会报错但是仅能访问node3结点

[root@node1 ~]# ipvsadm -L
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  node1:http rr
  -> node3:http                   Route   1      2          0         

重启node2的httpd服务

[root@node2 ~]# systemctl start httpd.service 

[root@node1 ~]# ipvsadm -L
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  node1:http rr
  -> node2:http                   Route   1      0          0         
  -> node3:http                   Route   1      2          0