keepalived configure virtual IP (VIP) to achieve hot standby backup and automatic switchover

Background: Why do this thing, to write this article

The domain of our project points to 172.22.90.239, but in fact we did this machine, which is a virtual ip, only 172.22.90.230, why the request 239 actually points to 230 machines?

And communicated prior to operation and maintenance, they do not remember. Old-dimensional shipped a few years ago to do. They just listen to the mouth of a noun: keepalived & VIP, Baidu a wave of learning.

Practical operation process

Physical machine is ready: 172.22.90.171 and 172.22.90.170 two

1. Install keepalived (two to be fitted):

yum install keepalived

2. modify the configuration file, delete /etc/keepalived/keepalived.conf, and then re-create a /etc/keepalived/keepalived.conf

we /etc/keepalived/keepalived.conf

172.22.90.171 configuration:

{global_defs 
notification_email { 
    [email protected] # fault contact 
 } 
 
notification_email_from [email protected] # fault sender 
    smtp_server 127.0 . 0.1 
    smtp_connect_timeout 30 
    the router_id of the modifications to LVS_MASTER #BACKUP LVS_BACKUP 
 } 
 

vrrp_script chk_nginx { 
     Script " / etc / keepalived / nginx_check .sh "     script path # nginx state detection 
     interval the . 1                     # detection interval lS 
     weight - 2                    # script if condition is established, the weight - 2 
  } 

  vrrp_instance VI_1 {
      state MASTER # service state; the MASTER (operating state) the BACKUP (standby) 
      interface bond0 # binding the VIP card 
      virtual_router_id 74         # virtual routing ID, host, the standby node must be consistent 
      mcast_src_ip 172.22 . 90.171   # local IP 
      higher priority nopreempt # setting, abnormal responses to solve the problem again preempted 
      priority 100                 # priority; range: 0 ~ 254 ; the mASTER> the bACKUP 
      advert_int . 1                 # multicast transmission interval, and backup nodes must be consistent, the default lS 
      authentication verification information {# ; backup nodes must be consistent 
          auth_type PASS # VRRP authentication type, PASS, AH two kinds 
          auth_pass1111           # the VRRP authentication password, at the same vrrp_instance, the master and slave must use the same password for communication 
      } 
       track_script {# The track_script block added instance configuration block 
          chk_nginx # perform Nginx monitored service 
      } 
      virtual_ipaddress {# virtual IP pool, a main , standby node must be consistent, you may define a plurality of the VIP 
          172.22 . 90.237            # virtual the IP 
      } 
  }

172.22.90.170 configuration:

{global_defs 
notification_email { 
    [email protected] # fault contact 
 } 
 
notification_email_from [email protected] # fault sender 
    smtp_server 127.0 . 0.1 
    smtp_connect_timeout 30 
    the router_id of the modifications to LVS_BACKUP #BACKUP LVS_BACKUP 
 } 
 

vrrp_script chk_nginx { 
     Script " / etc / keepalived / nginx_check .sh "     script path # nginx state detection 
     interval the . 1                     # detection interval lS 
     weight - 2                    # script if the condition is satisfied, - weights 2 
  }
 
  vrrp_instance VI_1 {
      state BACKUP # service state; the MASTER (operating state) the BACKUP (standby) 
      interface bond0 # binding the VIP card, to see if the card is currently used ifconfig under 
      virtual_router_id 74         # virtual routing ID, host, the standby node must be consistent, indicates a cluster within 
      mcast_src_ip 172.22 . 90.170   # native IP 
      nopreempt # high priority setting to address the issue again after the abnormal responses to seize the 
      priority 90                 # priority; the range: 0 ~ 254 ; MASTER> BACKUP, if all BACKUP, that is, large value is a front 
      advert_int . 1                 # multicast transmission interval, and backup nodes must be consistent, the default lS 
      authentication verification information {#; backup nodes must be consistent
          auth_type PASS # VRRP authentication type, PASS, AH two kinds 
          AUTH_PASS 1111           # the VRRP authentication password, at the same vrrp_instance, the master and slave must use the same password for communication 
      } 
       track_script {# instance added to a block configuration block track_script 
          perform chk_nginx # Nginx monitored service 
      } 
      virtual_ipaddress {# virtual IP pool, and backup nodes must be consistent, may define a plurality of the VIP 
          172.22 . 90.237            # virtual IP 
      } 
  }

3. After modifying the configuration files, restart the two machines keepalived:

systemctl restart keepalived

4, finally can test wave

Lord stopped keepalived service: systemctl stop keepalived cut close nginx test wave

Finally, we emphasize that: If the domain name is bound to a nginx, single point of failure unsafe, can be used to make highly available keepalived, binding two machines.

End!