一，Keepalived

解決單臺服務器承擔應用存在的單點故障的危險

介紹

專為LVS和HA設計的一款健康的健康檢查工具

• 支持故障自動切換
• 支持節點健康狀態檢查
• 官方網站：http://www.keepalived.org/

二，搭建LVS+Keepalived

• VRRP （虛擬路由冗余協議）針對對路由器的一種備份解決方案
• Keepalived可實作多機熱備，沒個熱備組可有多臺服務器
• 咱們是雙機熱備，雙機熱備的故障切換是由虛擬ip地址的漂移來實作的，適用于各種應用服務器

準備環境：

依賴于LVS-DR的操作基礎上，添加了備調度器，和更改了一下配置，

主調度器配置：

1.安裝Keepalived ipvsadm

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

2.配置keepalived.conf 組態檔

[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
        }
    }

區域配置模塊解釋：
global_defs { ：定義本路由器的服務器router_id
vrrp_instance VI_1 { ：定義VRRP熱備實列
virtual_ipaddress { ：定義漂移地址（VIP），可以是多個
virtual_server 192.168.100.10 80 { ：定義虛擬服務器地址（VIP）、埠
real_server 192.168.100.26 80 { ：定義WEB站點的地址，埠

3.啟動keepalived和開機自啟，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     #開啟lo:0
ifconfig   

5.查看配置下負載策略

[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資訊

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.調整/proc回應引數（內核引數優化）

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

備調度器配置：

咱們只需要配置keepalive 組態檔設定優先升級，router_id，bakup（備）
LVS的調度規則咱們也在keepalived.conf組態檔里，可直接生成

1.安裝Keepalived ipvsadm

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

2.配置keepalived.conf 組態檔

[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.啟動keepalived和開機自啟，ipvsadm

systemctl start keepalived    
systemctl enable keepalived
systemctl enable ipvsadm

4.查看配置下負載策略

[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，超鏈接（搭建web，nfs的）

還有三臺服務器未配置（web1,web2, nfs存盤）
web服務器和nfs存盤服務，見博主分類負載群集的LVS-DR模式部署
參考web和nfs部分步驟就行 下面是超鏈接：
鏈接：參看web，nfs存盤搭建步驟…

四，驗證LVS+Keepalived

通過cmd驗證下，是否做故障切換，vip地址轉移！！

1.先驗證正常的：

2.一直ping vip地址；讓主調度器斷開，看看mac地址是否變化，vip地址是否漂移

3.查看vip地址是否漂移到備調度器

ip addr show

 ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:9e:cf:4e brd ff:ff:ff:ff:ff:ff
    inet   <192.168.100.29/24>    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::f50a:6f87:cda8:5a2d/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever