Keeping MySQL highly available

keeplived Realization mysql High availability

Prerequisite

 Two sets of server It's all installed mariadb
server1:  10.243.68.158
server2:  10.243.68.159
virtual ip：10.243.68.160

install keepalived

• download keepalived Of rpm package ：keepalived-1.3.5-8.el7_6.x86_64.rpm

• install keeepalived

[[email protected] ~]# ll
total 356
-rw-r--r--. 1 root root 210 Feb 25 03:33 chk_rtm.sh
-rw-r--r--. 1 root root 336976 Feb 25 03:33 keepalived-1.3.5-8.el7_6.x86_64.rpm
-rw-r--r--. 1 root root 690 Feb 25 03:33 keepalived.conf
-rw-r--r--. 1 root root 1113 Feb 25 03:33 my.cnf
-rw-r--r--. 1 root root 10249 Feb 25 03:33 zabbix_agentd.conf
[[email protected] ~]# rpm -ivh keepalived-1.3.5-8.el7_6.x86_64.rpm
warning: keepalived-1.3.5-8.el7_6.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:keepalived-1.3.5-8.el7_6 ################################# [100%]
[[email protected] ~]#

To configure keepalived

To configure 10.243.68.158 server Configuration modification file /etc/keepalived/keepalived.conf as follows ：

[[email protected] ~]# cat /etc/keepalived/keepalived.conf
global_defs {
   notification_email {
        [email protected]
   }
   notification_email_from [email protected]
   smtp_server root
   smtp_connect_timeout 30
   router_id RTM       # Load balancing flag , It should be unique in the LAN .
   vrrp_skip_check_adv_addr
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script chk_rtm {  
    script "/etc/keepalived/chk_rtm.sh"  
    interval 3  
    weight -20  
}

vrrp_instance VI_1 {
    state BACKUP
    interface enp0s3 # network card 
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
	track_script {  
        chk_rtm 
    }
    virtual_ipaddress {
        10.243.68.160
    }
}

To configure 10.243.68.159 server Configuration modification file /etc/keepalived/keepalived.conf as follows ：

[[email protected] ~]# cat /etc/keepalived/keepalived.conf
global_defs {                ### Global configuration 
   notification_email {      ###keepalived The destination address of the email sent in case of failure 
        [email protected]
   }
   notification_email_from [email protected]      ###keepalived The source address of the email sent in case of failure 
   smtp_server root                            ### mail smtp Address 
   smtp_connect_timeout 30                     ### Connect smtp Timeout time 
   router_id RTM
   vrrp_skip_check_adv_addr
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script chk_rtm {    ###  Check performed mysql Script for , If mysql Hang up , The server The priority of is reduced 20
    script "/etc/keepalived/chk_rtm.sh"  
    interval 3  
    weight -20  
}

vrrp_instance VI_1 {            ## The instance configuration ,VI_1 For instance name , Modifiable 
    state BACKUP              ### state , It can be MASTER or BACKUP
    interface enp0s3           ### node IP Network card of , For hair VRRP package .
    virtual_router_id 51      ## Example of ID
    priority 100                 ### priority , The higher the priority, the higher 
    advert_int 1               ### Heartbeat interval , I can't receive my heartbeat for a second   The standby node takes over 
    authentication {          ### Password authentication between services 
        auth_type PASS
        auth_pass 1111
    }
	track_script {   ## Configure script check mysql Normal service 
        chk_rtm 
    }
    virtual_ipaddress {   ##vip binding , Bound to the interface  Set the network card 
        10.243.68.160
    }
}

Add script file chk_rtm.sh Executable rights ：

[[email protected] keepalived]# pwd
/etc/keepalived
[[email protected] keepalived]# ll
total 8
-rw-r--r--. 1 root root 218 Feb 21 20:25 chk_rtm.sh
-rw-r--r--. 1 root root 728 Feb 21 19:08 keepalived.conf
[[email protected] keepalived]# chmod +x chk_rtm.sh
[[email protected] keepalived]# ll
total 8
-rwxr-xr-x. 1 root root 218 Feb 21 20:25 chk_rtm.sh
-rw-r--r--. 1 root root 728 Feb 21 19:08 keepalived.conf

Check the script

#!/bin/bash

MYSQL_PROCESS_EXISTED=$(systemctl status mysql | grep "active (running)" | wc -l)

if [ "${MYSQL_PROCESS_EXISTED}" == "1" ];then
    exit 0
else
    exit 1
fi

restart keepalived

[[email protected] keepalived]#systemctl enable keepalived

test

1.  In two server The terminal execution of ip a  see server Is there a virtual ip：10.243.68.160
   [[email protected] keepalived]#ip a
2.  Virtual in ip Of server Stop on the terminal mysql service , View virtual ip Whether it exists in another server