About Keepalived

Keepalived is originally designed for LVS, which is specially used to monitor the status of each service node in the cluster system. It detects the status of each service node according to the third, fourth and fifth layer switching mechanisms of the TCP/IP reference model. If a server node is abnormal, or the work fails, keepalived will detect it and set the failed server nodes from the set In the group system, these tasks are all done automatically without human intervention. What needs to be done manually is only to repair the failed service nodes.

Topology of this experiment:

Experimental steps:

Synchronize the time of the machines in the cluster, turn off the firewall and selinux

ntpdate cn.pool.ntp.org
systemctl stop firewalld.service
setenforce 0

Operation on lvs1/2

1. Download necessary tools

   	yum install gcc gcc-c++ openssl-devel.x86_64 -y  
   

2. Download keepalived and LVS tools
   Website: https://keepalived.org

     wget https://keepalived.org/software/keepalived-2.0.10.tar.gz
     yum install ipvsadm.x86_64 -y  
   

3. Install and compile keepalived

   	tar -xzf keepalived-2.0.10.tar.gz -C /usr/local/src/
   	cd /usr/local/src/keepalived-2.0.10/
   	mkdir /data
       yum install libnl-devel.x86_64 -y
   	./configure --prefix=/data/kepalived
   

   

   	[root@master1 keepalived-2.0.10]# make && make install
   

4. . configure startup

    	cp /data/kepalived/etc/init.d/keepalived /etc/init.d/
      cp /data/kepalived/etc/sysconfig/keepalived /etc/sysconfig/
      mkdir /etc/keepalived
      cp /data/kepalived/etc/keepalived/keepalived.conf /etc/keepalived/
   

5. Modify profile

   	vim /etc/keepalived/keepalived.conf
   

   #Profile of the master node
   ! Configuration File for keepalived
   
   global_defs {
   notification_email {
   	 acassen@firewall.loc
     	}
     	notification_email_from Alexandre.Cassen@firewall.loc
     	smtp_server 127.0.0.1
     	smtp_connect_timeout 30
     	router_id LVS_1
   }
   
   vrrp_instance VI_1 {
   	 state MASTER  
    	interface eth0
    	lvs_sync_daemon_interface eth0
    	virtual_router_id 51
    	priority 150    
   	 advert_int 1
   	 authentication {
       	 auth_type PASS        
        	auth_pass 1111    
   	}    	
   	virtual_ipaddress {        
       	 192.168.192.123
   	}
   }
   
   virtual_server 192.168.192.123 80 {    
   	 delay_loop 6    
   	lb_algo wrr     
   	lb_kind DR    
   	nat_mask 255.255.255.255
   	persistence_timeout 300   
   	protocol TCP
   
   	real_server 192.168.192.139 80 {
       	weight 1
      	 	TCP_CHECK {
       	    connect_timeout 8        
           	nb_get_retry 3        
           	delay_before_retry 3        
           	connect_port 80
           	}    
      	 }
   
   	real_server 192.168.192.140 80 {        
       	weight 1        
      	 TCP_CHECK {        
      	     	connect_timeout 8        
      	     	nb_get_retry 3        
       	    delay_before_retry 3        
           	conect_port 80        
       	}    
    }
   }
   
   #Profile from node
   ! Configuration File for keepalived
   
   global_defs {
   notification_email {
   	 acassen@firewall.loc
   	  }
     	notification_email_from Alexandre.Cassen@firewall.loc
     	smtp_server 127.0.0.1
    	 smtp_connect_timeout 30
     	router_id LVS_1
   }	
   
   vrrp_instance VI_1 {
      state BACKUP
      interface eth0
      lvs_sync_daemon_interface eth0
      virtual_router_id 51
    	priority 100
    	advert_int 1
    	authentication {
       	 auth_type PASS        
        	auth_pass 1111    
   	}    
   	virtual_ipaddress {
       	 192.168.192.123
    }
   }
   
   virtual_server 192.168.192.123 80 {    
    delay_loop 6    
    lb_algo wrr     
    lb_kind DR    
    nat_mask 255.255.255.255
    persistence_timeout 300   
    protocol TCP
    real_server 192.168.192.140 80 {
   	    weight 1
       	TCP_CHECK {
           	connect_timeout 8        
          		nb_get_retry 3        
           	delay_before_retry 3        
           	connect_port 80
          	}    
       }
   
    real_server 192.168.192.139 80 {        
   	    weight 1        
       	TCP_CHECK {        
           	connect_timeout 8        
           	nb_get_retry 3        
           	delay_before_retry 3        
           	conect_port 80        
       	}    
   	}
   }
   

6. Turn on services and view LVS

   systemctl start keepalived
   

   

Operation on RS1/2 node

1. Disable responding to ARP requests to VIP s
   Because of the DR model based on LVS, we need to set the local VIP to not respond to arp requests from external hosts

   echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
   echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
   echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
   echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
   

2. Set vip

   ifconfig lo:0 192.168.192.123 netmask 255.255.255.255
   

3. Configure pages for httpd

   yum install httpd.x86_64 -y
   
   #192.168.192.139
   echo web 139 > /var/www/html/index.html
   
   #192.168.192.140
   echo web 140 > /var/www/html/index.html
   

test

View LVS configuration

ipvsadm -Ln

Testing at clien

The configuration file of keepalived is in / etc/keepalived/keepalived.conf by default, which is not stored at will