数据库软件目录: /opt/mysql/
数据库数据目录: /data/{master20,slave21,slave22}/{data,binlog}
主库端口3320
从库端口分别为3321,3322

配置文件如下:
cat > /data/master20/my.cnf <<EOF
[mysqld]
basedir=/opt/mysql/
datadir=/data/master20/data
socket=/data/master20/mysql.sock
server_id=100
port=3320
secure-file-priv=/tmp     # 配置的数据库安全路径, 能在数据库界面中直接导出结果到该目录下.
autocommit=0
log_bin=/data/master20/binlog/master20-bin
binlog_format=row
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
user=mysql
character_set_server = utf8mb4

[mysql]
prompt=master20 [\\d]>
EOF


cat > /data/slave21/my.cnf <<EOF
[mysqld]
basedir=/opt/mysql/
datadir=/data/slave21/data
socket=/data/slave21/mysql.sock
server_id=110
port=3321
secure-file-priv=/tmp
autocommit=0
log_bin=/data/slave21/binlog/slave21-bin
binlog_format=row
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
user=mysql
character_set_server = utf8mb4

[mysql]
prompt=slave21 [\\d]>
EOF


cat > /data/slave22/my.cnf <<EOF
[mysqld]
basedir=/opt/mysql/
datadir=/data/slave22/data
socket=/data/slave22/mysql.sock
server_id=120
port=3322
secure-file-priv=/tmp
autocommit=0
log_bin=/data/slave22/binlog/slave22-bin
binlog_format=row
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
user=mysql
character_set_server = utf8mb4

[mysql]
prompt=slave22 [\\d]>
EOF

mysqld --initialize-insecure --user=mysql --basedir=/opt/mysql  --datadir=/data/master20/data
mysqld --initialize-insecure --user=mysql --basedir=/opt/mysql  --datadir=/data/slave21/data
mysqld --initialize-insecure --user=mysql --basedir=/opt/mysql  --datadir=/data/slave22/data

cd /etc/systemd/system

cp mysqld.service master20.service
cp mysqld.service slave21.service
cp mysqld.service slave22.service

vim master20.service
ExecStart=/opt/mysql/bin/mysqld  --defaults-file=/data/master20/my.cnf
vim slave21.service
ExecStart=/opt/mysql/bin/mysqld  --defaults-file=/data/slave21/my.cnf
vim slave22.service
ExecStart=/opt/mysql/bin/mysqld  --defaults-file=/data/slave22/my.cnf

chown -R mysql.mysql /data/*

systemctl start master20.service
systemctl start slave21.service
systemctl start slave22.service

GTID(Global Transaction ID)是对于一个已提交事务的唯一编号，并且是一个全局(主从复制)唯一的编号。
它的官方定义如下：
GTID = source_id ：transaction_id
7E11FA47-31CA-19E1-9E56-C43AA21293967:29    # gtid编号的格式
什么是sever_uuid，和Server-id 区别？
核心特性: 全局唯一,具备幂等性

gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1

gtid-mode=on                        --启用gtid类型，否则就是普通的复制架构
enforce-gtid-consistency=true       --强制GTID的一致性
log-slave-updates=1                 --slave更新是否记入日志

master:3320
slave:3321,3322

3320:
grant replication slave  on *.* to repl@‘%‘ identified by ‘123‘;

21\22:
change master to 
master_host=‘10.0.0.51‘,
MASTER_PORT=3320,
master_user=‘repl‘,
master_password=‘123‘ ,
MASTER_AUTO_POSITION=1;

start slave;