MySQL5.7主从添加新从库的方法

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mysql 主从复制，不停机添加新从节点：

1、主库创建账号：

修改主库repl密码：

show master status;

alter user repl@'%' identified by '123456';

grant replication slave,replication client on *.* to 'repl'@'%';

flush privilegs;

2、从库配置（创建从库数据库过程简略）：

开启binlog

[root@Centos_TP data1]# cat /etc/my.cnf

[mysqld]

#datadir=/var/lib/mysql

#Socket=/var/lib/mysql/mysql.sock

#user=mysql

# Disabling symbolic-links is recommended to prevent assorted security risks

symbolic-links=0

basedir=/usr/local/mysql

datadir=/data1/data

socket=/tmp/mysql.sock

port=3306

server-id =60182

replicate-wild-ignore-table=mysql.%

replicate-wild-ignore-table=perfORMance_schema.%

replicate-wild-ignore-table=information_schema.%

replicate-wild-ignore-table=sys.%

log-bin = /data1/log/mysql-bin

binlog_format = MIXED

skip-slave-start = 1

expire_logs_days=3

#validate_passWord_policy=0

#validate_password_length=3

relay-log-index=/data1/log/mysql-relay

relay-log=/data1/log/mysql-relay

log-bin=/data1/log/mysql-bin

#log-error=log.err

explicit_defaults_for_timestamp=true

[mysqld_safe]

log-error=/data1/log/mysql.err

pid-file=/data1/tmp/mysqld.pid

初始化数据库：

正常初始化：

[root@centos_TP bin]# ./mysqld --defaults-file=/etc/my.cnf  --initialize  --user=mysql

2020-01-14T08:48:27.965207Z 0 [Warning] InnoDB: New log files created, LSN=45790

2020-01-14T08:48:28.175008Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.

2020-01-14T08:48:28.270192Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: a2408f8d-36aa-11ea-a1c6-00505695cefc.

2020-01-14T08:48:28.273709Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.

2020-01-14T08:48:28.278708Z 1 [Note] A temporary password is generated for root@localhost: (,%E6LnwWrrq

指定初始化配置文件：

/usr/local/mysql/bin/mysqld --defaults-file=/etc/my.cnf  --initialize  --user=mysql

#开启数据库

/usr/local/mysql/bin/mysqld_safe --defaults-file=/etc/my.cnf &

#登录数据库，修改root密码

mysql -p

之前初始化的密码

set sql_log_bin=0;

mysql> alter user root@'localhost' identified by '123456';

mysql>flush privileges;

set sql_log_bin=1;

增加root远程登录用户：

mysql> create user root@'%' identified by '123456';

Query OK, 0 rows affected (0.01 sec)

mysql> grant all privileges on *.* to root@'%';

mysql> flush privileges;

#创建slave账号

mysql> grant replication slave,replication client on *.* to 'repl'@'%' identified by '123456';

#在slave节点上执行

mysql> set global read_only=1;

#由于从库随时会提升成主库，不能写在配置文件里

3、备份主库：

[root@localhost dbdata]# mysqldump -uroot -p --routines --single_transaction --master-data=2 -B cat qc_bh > all.sql

参数说明：

--routines：导出存储过程和函数

--single_transaction：导出开始时设置事务隔离状态，并使用一致性快照开始事务，然后unlock tables;而lock-tables是锁住一张表不能写操作，直到dump完毕。

--master-data：默认等于1，将dump起始（change master to）binlog点和pos值写到结果中，等于2是将change master to写到结果中并注释。

4、从库创建数据库，并导入数据

将dump的数据拷贝到从库后开始导数据

mysql>

create database  cat;

create database  qc_bh;

mysql> source /data1/all.sql

...

Query OK, 0 rows affected (0.01 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected, 1 warning (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.01 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

5、查看备份文件的binlog 和 pos值

[root@centos_TP data1]# head -25 all.sql

-- MySQL dump 10.13  Distrib 5.7.20, for linux-glibc2.12 (x86_64)

--

-- Host: localhost    Database: cat

-- ------------------------------------------------------

-- Server version       5.7.20-log

;

;

;

;

;

;

;

;

;

;

--

-- Position to start replication or point-in-time recovery from

--

-- CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000037', MASTER_LOG_POS=621697642;

--

-- Current Database: `cat`

可以看到 MASTER_LOG_FILE='mysql-bin.000037', MASTER_LOG_POS=621697642;

6、启动从库

mysql> change master to

   -> master_host='192.168.60.181',

   -> master_user='repl',

   -> master_password='123456',

   -> master_log_file='mysql-bin.000037',

   -> master_log_pos=621697642;

mysql> start slave;

Query OK, 0 rows affected (0.01 sec)

mysql> show slave status\G;

*************************** 1. row ***************************

              Slave_IO_State: Queueing master event to the relay log

                 Master_Host: 192.168.60.181

                 Master_User: repl

                 Master_Port: 3306

               Connect_Retry: 60

             Master_Log_File: mysql-bin.000037

         Read_Master_Log_Pos: 677960018

              Relay_Log_File: mysql-relay.000002

               Relay_Log_Pos: 24887

       Relay_Master_Log_File: mysql-bin.000037

            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: mysql.%,performance_schema.%,information_schema.%,sys.%

                  Last_Errno: 0

                  Last_Error:

                Skip_Counter: 0

         Exec_Master_Log_Pos: 621722209

             Relay_Log_Space: 56262899

             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: 6606

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: 60181

                 Master_UUID: a524c954-c8a8-11e9-8082-00505697e9db

            Master_Info_File: /data1/data/master.info

                   SQL_Delay: 0

         SQL_Remaining_Delay: NULL

     Slave_SQL_Running_State: Reading event from the relay log

          Master_Retry_Count: 86400

                 Master_Bind:

     Last_IO_Error_Timestamp:

    Last_SQL_Error_Timestamp:

              Master_SSL_Crl:

          Master_SSL_Crlpath:

          Retrieved_Gtid_Set:

           Executed_Gtid_Set:

               Auto_Position: 0

        Replicate_Rewrite_DB:

                Channel_Name:

          Master_TLS_Version:

1 row in set (0.01 sec)

ERROR:

No query specified

显示：

看到IO和SQL线程均为YES，说明主从配置成功。

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

Read_Master_Log_Pos: 677960018表示一直在追binlog日志。

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