MySQL 5.7基于GTID的主从复制环境搭建（一主一从）

 

Preface

 

    As wel all know,replication base on GTID with row format of binary log is comprehensive used nowadays,especially in MySQL 5.7 version above.I'm going to demonstrate a simplest way to implement a replacation within two servers.

 

Framework

 

Hostname	IP/Port	Identity	OS Version	MySQL Version	GTID Mode	Binlog Format
zlm2	192.168.1.101/3306	master	CentOS 7.0	5.7.21	on	row
zlm3	192.168.1.102/3306	slave	CentOS 7.0	5.7.21	on	row

 

Procedure

 

Generate a new backup by mysqldump and send it to slave host.

 [root@zlm2 :: ~]
 #mysqldump -S /tmp/mysql3306.sock -p -A --single-transaction --master-data= > db3306_`date +%Y%m%d`.sql
 Enter password:
 Warning: A partial dump from a server that has GTIDs will by default include the GTIDs of all transactions, even those that changed suppressed parts of the database. If you don't want to restore GTIDs, pass --set-gtid-purged=OFF. To make a complete dump, pass --all-databases --triggers --routines --events. 

 [root@zlm2 :: ~]
 #ls -l|grep *.sql

 [root@zlm2 :: ~]
 #ls -l|grep db3306
 -rw-r--r--    root root     Jul  : db3306_20180710.sql

 [root@zlm2 :: ~]
 #scp db3306_20180710.sql 192.168.1.102:/data
 root@192.168.1.102's password:
 db3306_20180710.sql                                                                                                % 7161KB   .0MB/s   :    

 [root@zlm2 :: ~]
 #

Import the backup on slave host with mysql client tool.

 [root@zlm3 :: ~]
 #cd /data

 [root@zlm3 :: /data]
 #ls -l
 total
 drwxr-xr-x  mysql mysql       Jun   : backup
 -rw-r--r--  root  root   Jul  : db3306_20180710.sql
 drwxr-xr-x  mysql mysql       Apr  : mysql

 [root@zlm3 :: /data]
 #mysql -S /tmp/mysql3306.sock -p < db3306_20180710.sql
 Enter password:
 ERROR  (HY000) at line : @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty.

 //We cannot set global.gtid_purged while global.gtid_executed isn't empty before MySQL 8.0.
 //The only way is executing "reset master;" on slave.

 [root@zlm3 :: /data]
 #mysql
 Welcome to the MySQL monitor.  Commands end with ; or \g.
 Your MySQL connection id is
 Server version: 5.7.-log MySQL Community Server (GPL)

 Copyright (c) , , Oracle and/or its affiliates. All rights reserved.

 Oracle is a registered trademark of Oracle Corporation and/or its
 affiliates. Other names may be trademarks of their respective
 owners.

 Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

 (root@localhost mysql3306.sock)[(none)]>show master status;
 +------------------+----------+--------------+------------------+------------------------------------------------------------------------------------------------------------------------------------+
 | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                                                                                                                  |
 +------------------+----------+--------------+------------------+------------------------------------------------------------------------------------------------------------------------------------+
 | mysql-bin. |       |              |                  | 1b7181ee-6eaf-11e8-998e-080027de0e0e:-,
 5c77c31b-4add-11e8-81e2-080027de0e0e:-,
 ed142e35-6ed1-11e8-86c6-080027de0e0e:- |
 +------------------+----------+--------------+------------------+------------------------------------------------------------------------------------------------------------------------------------+
  row in set (0.00 sec)

 (root@localhost mysql3306.sock)[(none)]>reset master; //After execute it,binlogs on slave will be deleted.
 Query OK,  rows affected (0.02 sec)

 (root@localhost mysql3306.sock)[(none)]>show master status;
 +------------------+----------+--------------+------------------+-------------------+
 | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
 +------------------+----------+--------------+------------------+-------------------+
 | mysql-bin. |       |              |                  |                   |
 +------------------+----------+--------------+------------------+-------------------+
  row in set (0.00 sec)

 (root@localhost mysql3306.sock)[(none)]>exit
 Bye

 [root@zlm3 :: /data]
 #mysql -S /tmp/mysql3306.sock -p < db3306_20180710.sql //Import backed data again.
 Enter password: 

 [root@zlm3 :: /data]
 #

Create replication user 'replica' with password 'replica' on master host.

 (root@localhost mysql3306.sock)[(none)]>create user replica@'192.168.1.%' identified by 'replica';
 Query OK,  rows affected (0.01 sec)

 (root@localhost mysql3306.sock)[(none)]>grant replication slave on *.* to replica@'192.168.1.%';
 Query OK,  rows affected (0.00 sec)

 //You can also create the replication user before generating backup.
 //Take care of the operation of flushing privileges if there're any problem after executing "start salve;".

Set "change master ... " on slave host.

 (root@localhost mysql3306.sock)[(none)]>change master to \
     -> master_host='192.168.1.101', \
     -> master_port=, \
     -> master_user='replica', \
     -> master_password='replica', \
     -> master_auto_position=; //As we are using GTID mode to implement replication,this is indispensable.
 Query OK,  rows affected,  warnings (0.02 sec)

 //If you've forgotten the syntax,you can type "help change master to" to know details.

 (root@localhost mysql3306.sock)[(none)]>show warnings;
 +-------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 | Level | Code | Message                                                                                                                                                                                                                                                                              |
 +-------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 | Note  |  | Sending passwords in plain text without SSL/TLS is extremely insecure.                                                                                                                                                                                                               |
 | Note  |  | Storing MySQL user name or password information in the master info repository is not secure and is therefore not recommended. Please consider using the USER and PASSWORD connection options for START SLAVE; see the 'START SLAVE Syntax' in the MySQL Manual for more information. |
 +-------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
  rows in set (0.00 sec)

 //Ignore these above warnings.

 (root@localhost mysql3306.sock)[(none)]>show slave status\G
 *************************** . row ***************************
                Slave_IO_State:
                   Master_Host: 192.168.1.101
                   Master_User: replica
                   Master_Port:
                 Connect_Retry:
               Master_Log_File:
           Read_Master_Log_Pos:
                Relay_Log_File: relay-bin.
                 Relay_Log_Pos:
         Relay_Master_Log_File:
              Slave_IO_Running: No
             Slave_SQL_Running: No
               Replicate_Do_DB:
           Replicate_Ignore_DB:
            Replicate_Do_Table:
        Replicate_Ignore_Table:
       Replicate_Wild_Do_Table:
   Replicate_Wild_Ignore_Table:
                    Last_Errno:
                    Last_Error:
                  Skip_Counter:
           Exec_Master_Log_Pos:
               Relay_Log_Space:
               Until_Condition: None
                Until_Log_File:
                 Until_Log_Pos:
            Master_SSL_Allowed: No
            Master_SSL_CA_File:
            Master_SSL_CA_Path:
               Master_SSL_Cert:
             Master_SSL_Cipher:
                Master_SSL_Key:
         Seconds_Behind_Master: NULL
 Master_SSL_Verify_Server_Cert: No
                 Last_IO_Errno:
                 Last_IO_Error:
                Last_SQL_Errno:
                Last_SQL_Error:
   Replicate_Ignore_Server_Ids:
              Master_Server_Id:
                   Master_UUID: 1b7181ee-6eaf-11e8-998e-080027de0e0e
              Master_Info_File: mysql.slave_master_info
                     SQL_Delay:
           SQL_Remaining_Delay: NULL
       Slave_SQL_Running_State:
            Master_Retry_Count:
                   Master_Bind:
       Last_IO_Error_Timestamp:
      Last_SQL_Error_Timestamp:
                Master_SSL_Crl:
            Master_SSL_Crlpath:
            Retrieved_Gtid_Set:
             Executed_Gtid_Set: 1b7181ee-6eaf-11e8-998e-080027de0e0e:-,
 ed142e35-6ed1-11e8-86c6-080027de0e0e:-
                 Auto_Position:
          Replicate_Rewrite_DB:
                  Channel_Name:
            Master_TLS_Version:
  row in set (0.00 sec)

 //The output shows the details about master info.

Execute "start slave;" on slave host.

 (root@localhost mysql3306.sock)[(none)]>start slave;
 Query OK,  rows affected (0.00 sec)

 (root@localhost mysql3306.sock)[(none)]>show slave status\G
 *************************** . row ***************************
                Slave_IO_State: Waiting for master to send event
                   Master_Host: 192.168.1.101
                   Master_User: replica
                   Master_Port:
                 Connect_Retry:
               Master_Log_File: mysql-bin.
           Read_Master_Log_Pos:
                Relay_Log_File: relay-bin.
                 Relay_Log_Pos:
         Relay_Master_Log_File: mysql-bin.
              Slave_IO_Running: Yes //IO Thread is working normally.
             Slave_SQL_Running: Yes //SQL Thread is working normally.
               Replicate_Do_DB:
           Replicate_Ignore_DB:
            Replicate_Do_Table:
        Replicate_Ignore_Table:
       Replicate_Wild_Do_Table:
   Replicate_Wild_Ignore_Table:
                    Last_Errno:
                    Last_Error:
                  Skip_Counter:
           Exec_Master_Log_Pos:
               Relay_Log_Space:
               Until_Condition: None
                Until_Log_File:
                 Until_Log_Pos:
            Master_SSL_Allowed: No
            Master_SSL_CA_File:
            Master_SSL_CA_Path:
               Master_SSL_Cert:
             Master_SSL_Cipher:
                Master_SSL_Key:
         Seconds_Behind_Master:
 Master_SSL_Verify_Server_Cert: No
                 Last_IO_Errno:
                 Last_IO_Error:
                Last_SQL_Errno:
                Last_SQL_Error:
   Replicate_Ignore_Server_Ids:
              Master_Server_Id:
                   Master_UUID: 1b7181ee-6eaf-11e8-998e-080027de0e0e
              Master_Info_File: mysql.slave_master_info
                     SQL_Delay:
           SQL_Remaining_Delay: NULL
       Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
            Master_Retry_Count:
                   Master_Bind:
       Last_IO_Error_Timestamp:
      Last_SQL_Error_Timestamp:
                Master_SSL_Crl:
            Master_SSL_Crlpath:
            Retrieved_Gtid_Set: 1b7181ee-6eaf-11e8-998e-080027de0e0e:-
             Executed_Gtid_Set: 1b7181ee-6eaf-11e8-998e-080027de0e0e:-,
 ed142e35-6ed1-11e8-86c6-080027de0e0e:-
                 Auto_Position:
          Replicate_Rewrite_DB:
                  Channel_Name:
            Master_TLS_Version:
  row in set (0.00 sec)

    Okay,we are well-off to get a replication architecture now.Is that simple?

 

Variables relevant to GTID on master host.

 +---------------------------------------------------+------------------------------------------------------------------------------------------+
 | Variable_name                                     | Value                                                                                    |
 +---------------------------------------------------+------------------------------------------------------------------------------------------+
 | binlog_gtid_simple_recovery                       | ON                                                                                       |
 | enforce_gtid_consistency                          | ON                                                                                       |
 | group_replication_allow_local_disjoint_gtids_join | OFF                                                                                      |
 | group_replication_gtid_assignment_block_size      |                                                                                   |
 | gtid_executed_compression_period                  |                                                                                      |
 | gtid_mode                                         | ON                                                                                       |
 | gtid_next                                         | AUTOMATIC                                                                                |
 | gtid_owned                                        |                                                                                          |
 | gtid_purged                                       | 1b7181ee-6eaf-11e8-998e-080027de0e0e:-,
 ed142e35-6ed1-11e8-86c6-080027de0e0e:- |
 | session_track_gtids                               | OFF                                                                                      |
 +---------------------------------------------------+------------------------------------------------------------------------------------------+
  rows in set (0.00 sec)

Variables relevant to GTID on master host.

 (root@localhost mysql3306.sock)[(none)]>show variables like '%gtid%';
 +---------------------------------------------------+------------------------------------------------------------------------------------------+
 | Variable_name                                     | Value                                                                                    |
 +---------------------------------------------------+------------------------------------------------------------------------------------------+
 | binlog_gtid_simple_recovery                       | ON                                                                                       |
 | enforce_gtid_consistency                          | ON                                                                                       |
 | group_replication_allow_local_disjoint_gtids_join | OFF                                                                                      |
 | group_replication_gtid_assignment_block_size      |                                                                                   |
 | gtid_executed_compression_period                  |                                                                                      |
 | gtid_mode                                         | ON                                                                                       |
 | gtid_next                                         | AUTOMATIC                                                                                |
 | gtid_owned                                        |                                                                                          |
 | gtid_purged                                       | 1b7181ee-6eaf-11e8-998e-080027de0e0e:-,
 ed142e35-6ed1-11e8-86c6-080027de0e0e:- |
 | session_track_gtids                               | OFF                                                                                      |
 +---------------------------------------------------+------------------------------------------------------------------------------------------+
  rows in set (0.00 sec)

    We find out that they're almost the same except the variable of "gtid_purged" on slave is larger than it on master host.It's normal.The value will continuously increase while binlogs(actually relay logs) are purged after applying them on slave from time to time if only sql_thread is running.