mysql两主一从的搭建示例代码：

[root@localhostetc]#catmy.cnf
#Foradviceonhowtochangesettingspleasesee
#http://dev.mysql.com/doc/refman/8.0/en/server-configuration-defaults.html
[mysqld]
#
#Removeleading#andsettotheamountofRAMforthemostimportantdata
#cacheinMySQL.Startat70%oftotalRAMfordedicatedserver,else10%.
#innodb_buffer_pool_size=128M
#
#Removetheleading"#"todisablebinarylogging
#Binaryloggingcaptureschangesbetweenbackupsandisenabledby
#default.It'sdefaultsettingislog_bin=binlog
#disable_log_bin
#
#Removeleading#tosetoptionsmainlyusefulforreportingservers.
#TheserverdefaultsarefasterfortransactionsandfastSELECTs.
#Adjustsizesasneeded,experimenttofindtheoptimalvalues.
#join_buffer_size=128M
#sort_buffer_size=2M
#read_rnd_buffer_size=2M
#
#Removeleading#toreverttopreviousvaluefordefault_authentication_plugin,
#thiswillincreasecompatibilitywitholderclients.Forbackground,see:
#https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_default_authentication_plugin
#default-authentication-plugin=mysql_native_password
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
[mysqld_muliti]
mysqld=/usr/bin/mysqld_safe
mysqladmin=/usr/bin/mysqladmin
user=root
password=123456
[mysqld178]
port=3306
datadir=/var/lib/mysqla
pid-file=/var/lib/mysqla/mysqld.pid
socket=/var/lib/mysqla/mysql.sock
user=mysql
server-id=3
[mysqld179]
port=3307
datadir=/var/lib/mysqlb
pid-file=/var/lib/mysqlb/mysqld.pid
socket=/var/lib/mysqlb/mysql.sock
user=mysql
server-id=3