MySQL单节点变更为主从节点

环境说明：

　　操作系统：CentOS 7.6

　　数据库版本：5.7

为了实验方便，同一台主机部署了两个实例，3306、3307 部署方案可参考 MySQL多实例部署：mysql多实例部署 - 太阳的阳ฅ - 博客园 (cnblogs.com)

一、主库配置

1、备份原先的配置文件，增加主从配置

vim /home/mysql/3306/my.cnf

[mysqld]
bind-address=0.0.0.0
port=3306
user=mysql
basedir=/home/mysql
datadir=/home/mysql/3306/data
socket=/home/mysql/3306/mysql.sock
log-error=/home/mysql/3306/mysql.err
pid-file=/home/mysql/3306/mysql.pid

slow_query_log = ON
slow_query_log_file = /home/mysql/3306/slow.log
long_query_time = 1

#character config
character_set_server=utf8mb4
symbolic-links=0

#新增配置
server-id=1
gtid_mode=ON
enforce_gtid_consistency=ON

binlog_format=row
expire_logs_days=7
max_binlog_size=512M
log-bin=/home/mysql/3306/logs/mysql-bin
log_bin_index=/home/mysql/3306/logs/mysql-bin.index
log-slave-updates = ON

2、创建对应的 logs 目录

# cd /home/mysql/
# mkdir {3306,3307}/logs
# chown mysql .mysql -R *

3、重启服务

守护进程方式启动的，杀掉进程重启

./bin/mysqld_safe --defaults-file=/home/mysql/3306/my.cnf &

4、登录数据库，配置主从同步账号

# ./bin/mysql -uroot -p -S /home/mysql/3306/mysql.sock
mysql> GRANT REPLICATION SLAVE ON *.* to 'repl'@'192.168.53.%' IDENTIFIED BY 'repl';
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> SHOW MASTER STATUS;
+------------------+----------+--------------+------------------+----------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                      |
+------------------+----------+--------------+------------------+----------------------------------------+
| mysql-bin.000001 |      448 |              |                  | 1c68d59d-6646-11ed-963e-000c298a317b:1 |
+------------------+----------+--------------+------------------+----------------------------------------+
1 row in set (0.00 sec)

mysql> SHOW VARIABLES LIKE '%gtid%';
+----------------------------------+-----------+
| Variable_name                    | Value     |
+----------------------------------+-----------+
| binlog_gtid_simple_recovery      | ON        |
| enforce_gtid_consistency         | ON        |
| gtid_executed_compression_period | 1000      |
| gtid_mode                        | ON        |
| gtid_next                        | AUTOMATIC |
| gtid_owned                       |           |
| gtid_purged                      |           |
| session_track_gtids              | OFF       |
+----------------------------------+-----------+
8 rows in set (0.01 sec)

二、从库配置

1、配置文件

vim /home/mysql/3307/my.cnf

[mysqld]
bind-address=0.0.0.0
port=3307
user=mysql
basedir=/home/mysql
datadir=/home/mysql/3307/data
socket=/home/mysql/3307/mysql.sock
log-error=/home/mysql/3307/mysql.err
pid-file=/home/mysql/3307/mysql.pid

slow_query_log = ON
slow_query_log_file = /home/mysql/3307/slow.log
long_query_time = 1

#character config
character_set_server=utf8mb4
symbolic-links=0

#新增配置
server-id=151
gtid_mode = ON
enforce_gtid_consistency = ON
skip-slave-start = true
expire_logs_days = 7
max_binlog_size  = 512M
read_only = ON

log-bin=/home/mysql/3307/logs/mysql-bin
log_bin_index = /home/mysql/3307/logs/mysql-bin.index
relay-log = /home/mysql/3307/logs/relay-log
relay-log-index = /home/mysql/3307/logs/relay-log-index
relay-log-info-file = /home/mysql/3307/logs/relay-log.info
log-slave-updates=true
master-info-repository = table
relay-log-info-repository = table

2、参考主库重启命令，重新启动从库

3、配置slave 同步

# ./bin/mysql -uroot -p -S /home/mysql/3307/mysql.sock
mysql> CHANGE MASTER TO MASTER_HOST='192.168.53.123',MASTER_PORT=3306,MASTER_USER='repl',MASTER_PASSWORD='repl',MASSTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.02 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.53.123
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 448
               Relay_Log_File: relay-log.000002
                Relay_Log_Pos: 661
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 448
              Relay_Log_Space: 862
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
                  Master_UUID: 1c68d59d-6646-11ed-963e-000c298a317b
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 1c68d59d-6646-11ed-963e-000c298a317b:1
            Executed_Gtid_Set: 1c68d59d-6646-11ed-963e-000c298a317b:1
                Auto_Position: 1
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

ERROR: 
No query specified

配置完成

PS：如果出现sql 线程或者IO线程NO，可尝试将主库暂时锁表，说有数据备份出来导入从库，解锁再观察，注意先 stop slave;

mysqldump -S /home/mysql/3306/mysql.sock -u root -p --lock-all-tables  --master-data=2 --flush-logs --all-databases --triggers --routines --events > full.sql

./bin/mysql -uroot -p -S /home/mysql/3307/mysql.sock < full.sql