Kept dual machine hot standby

 1、 Realization keepalived+LVS-DR Highly available load balancing web to cluster around

 keepalived The role of ：
Support for automatic fail over
Support node health status check

2、keepalived Installation and configuration （ In the main 、 On the backup server ）

yum -y install keepalived ipvsadm

systemctl enable keepalived        （ Boot from boot ）

  Modify kernel parameter file , close ICMP Redirect

vim  /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

  master server keepalived.conf Configuration of

vim  /etc/keepalived/keepalived.conf
    （ The following is the modification ）

router_id LVS_DEVEL1                              （ This router ( The server ) The name of ）

state MASTER                                      （ Hot standby state ,MASTER Represents the primary server ） 
    interface ens33                               （ bearing VIP Physical interface of address ）      
    virtual_router_id 51                          （ Virtual router ID Number , Each hot standby group is consistent ）         
    priority 100                                  （ priority , The higher the value, the higher the priority ）  

virtual_ipaddress {
        200.0.0.100                               （ Specify the drift address , There can be multiple ）
        }

virtual_server 200.0.0.100 80 {                   （ Virtual server address ((ViP)、 port ） 
    delay_loop 15                                 （ Intervals between health checks ( second )）    
    lb_algo rr                                    （ polling (rr) Scheduling algorithm ）
    lb_kind DR                                    （ Direct routing ((DR) Cluster working mode ）
    nat_mask 255.255.255.0                   
    ! persistence_timeout 50                      （ Connection retention time ( second ), If enabled, please remove it ! Number ）
    protocol TCP                                      

real_server 200.0.0.4 80 {                         （ the second Web The address of the node ）          
        weight 1
        TCP_CHECK {
                connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        
                }
        }
real_server 200.0.0.4 80 {                         （ Third Web The address of the node ）          
        weight 1
        TCP_CHECK {
                connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        
                }
        }
}

Backup server keepalived.conf Configuration of

vim  /etc/keepalived/keepalived.conf

router_id LVS_DEVEL2

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90

 Other configurations are the same as the main service 

Start the service

systemctl   start  keepalived
systemctl   enable  keepalived

 3、web1 and web2 Server configuration

ifcfg-lo:0 Configure cluster ip Address 200.0.0.100, The subnet mask is 255.255.255.255

cd /etc/sysconfig/network-scripts
 
cp ifcfg-lo ifcfg-lo:0
 
vim ifcfg-lo:0
 
DEVICE=lo:0
IPADDR=200.0.0.100
NETMASK=255.255.255.255
ONBOOT=yes
 
ifup lo:0
 
 
vim /etc/rc.local
/sbin/route add -host 200.0.0.100 dev lo:0
 
 
route add -host 200.0.0.100 dev lo:0

  Close the part ARP The reply

vim /etc/sysctl.conf 
 
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.default.arp_ignore = 1
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
 
 
sysctl -p

install HTTP Create a test page

yum -y install httpd
 
vim /var/www/html/index.html
 
<h1>1111111<h1>    （web1 To configure ）
<h1>2222222<h1>    （web2 To configure ）
 
 
systemctl restart httpd
systemctl enable httpd