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一，Keepalived
- 介绍
二，搭建LVS+Keepalived
- 主调度器配置：
- 备调度器配置：
三，超链接（搭建web，nfs的）
四，验证LVS+Keepalived

一，Keepalived

解决单台服务器承担应用存在的单点故障的危险

介绍

专为LVS和HA设计的一款健康的健康检查工具

支持故障自动切换
支持节点健康状态检查
官方网站：http://www.keepalived.org/

二，搭建LVS+Keepalived

VRRP （虚拟路由冗余协议）针对对路由器的一种备份解决方案
Keepalived可实现多机热备，没个热备组可有多台服务器
咱们是双机热备，双机热备的故障切换是由虚拟ip地址的漂移来实现的，适用于各种应用服务器

准备环境：

依赖于LVS-DR的操作基础上，添加了备调度器，和更改了一下配置，


主调度器：	192.168.100.25 vip地址：ens33:0 192.168.100.100
备调度器:	192.168.100.29
web1：	192.168.100.26 vip地址：lo:0 192.168.100.100
web2：	192.168.100.27 vip地址：lo:0 192.168.100.100
nfs存储：	192.168.100.28

主调度器配置：

1.安装Keepalived ipvsadm

root@localhost ~]# yum -y install keepalived ipvsadm

2.配置keepalived.conf 配置文件

[root@localhost ~]# cd /etc/keepalived/
[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bakup
[root@localhost keepalived]# vi keepalived.conf
global_defs { 
   router_id HA_TEST_R1
}
vrrp_instance VI_1 { 
   state MASTER
   interface ens33
   virtual_router_id 1
   priority 100
   advert_int 1
   authentication { 
      auth_type PASS
      auth_pass 123456
   }
   virtual_ipaddress { 
      192.168.100.100
   }
}

virtual_server 192.168.100.100 80 { 
    delay_loop 15
    lb_algo rr
    lb_kind DR
    persistence 60
    protocol TCP

    real_server 192.168.100.26 80 { 
        weight 1
        TCP_CHECK { 
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 4
        }
    }
    real_server 192.168.100.27 80 { 
        weight 1
        TCP_CHECK { 
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 4
        }
    }

区域配置模块解释：
global_defs { ：定义本路由器的服务器router_id
vrrp_instance VI_1 { ：定义VRRP热备实列
virtual_ipaddress { ：定义漂移地址（VIP），可以是多个
virtual_server 192.168.100.10 80 { ：定义虚拟服务器地址（VIP）、端口
real_server 192.168.100.26 80 { ：定义WEB站点的地址，端口

3.启动keepalived和开机自启，ipvsadm

systemctl start keepalived    
systemctl enable keepalived
systemctl enable ipvsadm

4.配置vip地址192.168.100.100

[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# cp ifcfg-lo ifcfg-lo:0
[root@localhost network-scripts]# vi ifcfg-lo:0
DEVICE=lo:0
IPADDR=192.168.100.100
NETMASK=255.255.255.255
ONBOOT=yes

ifup lo:0     #开启lo:0
ifconfig

5.查看配置下负载策略

[root@localhost ]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.26:80            Route   1      0          0         
  -> 192.168.100.27:80            Route   1      0          0

6.查看vip信息

ip addr show

 ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:da:8c:3c brd ff:ff:ff:ff:ff:ff
    inet 《192.168.100.25/24》 brd 192.168.100.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 《192.168.100.100/32》scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::a33e:6402:8d1:c2aa/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

7.调整/proc响应参数（内核参数优化）

vi /etc/sysctl.conf 

net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.ens33.send_redirects = 0

sysctl  -p

备调度器配置：

咱们只需要配置keepalive 配置文件设置优先升级，router_id，bakup（备）
LVS的调度规则咱们也在keepalived.conf配置文件里，可直接生成

1.安装Keepalived ipvsadm

root@localhost ~]# yum -y install keepalived ipvsadm

2.配置keepalived.conf 配置文件

[root@localhost ~]# cd /etc/keepalived/
[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bakup
[root@localhost keepalived]# vi keepalived.conf

global_defs { 
   router_id HA_TEST_R2
}
vrrp_instance VI_1 { 
   state BACKUP
   interface ens33
   virtual_router_id 1
   priority 99
   advert_int 1
   authentication { 
      auth_type PASS
      auth_pass 123456
   }
   virtual_ipaddress { 
      192.168.100.100
   }
}

virtual_server 192.168.100.100 80 { 
    delay_loop 15
    lb_algo rr
    lb_kind DR
    persistence 60
    protocol TCP

    real_server 192.168.100.26 80 { 
        weight 1
        TCP_CHECK { 
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 4
        }
    }
    real_server 192.168.100.27 80 { 
        weight 1
        TCP_CHECK { 
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 4
        }
    }
}

3.启动keepalived和开机自启，ipvsadm

systemctl start keepalived    
systemctl enable keepalived
systemctl enable ipvsadm

4.查看配置下负载策略

[root@localhost ]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.26:80            Route   1      0          0         
  -> 192.168.100.27:80            Route   1      0          0

三，超链接（搭建web，nfs的）

还有三台服务器未配置（web1,web2, nfs存储）
web服务器和nfs存储服务，见博主分类负载群集的LVS-DR模式部署
参考web和nfs部分步骤就行下面是超链接：
链接：参看web，nfs存储搭建步骤…

四，验证LVS+Keepalived

通过cmd验证下，是否做故障切换，vip地址转移！！

1.先验证正常的：

2.一直ping vip地址；让主调度器断开，看看mac地址是否变化，vip地址是否漂移

3.查看vip地址是否漂移到备调度器