MySQL是一个关系型数据库管理系统，由瑞典MySQL AB 公司开发，属于 Oracle 旗下产品。MySQL 是最流行的关系型数据库管理系统之一，在 WEB 应用方面，MySQL是最好的 RDBMS (Relational Database Management System，关系数据库管理系统) 应用软件之一。
2、环境说明
两台linux虚拟主机
Linux操作系统版本：CentOS Linux release 7.6.1810
数据库版本：MySQL 5.7.26
IP：192.168.12.222、192.168.12.223
3、主从复制
3.1、MySQL
docker run -it -d --name mysql \ -e TZ="Asia/Shanghai" \ -p 3306:3306 \ -v /docker/data/mysql/data:/var/lib/mysql \ -v /docker/data/mysql/conf:/etc/mysql/conf.d \ -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7.26
3.2、配置文件
一般Linux中的MySQL配置文件都在/etc/my.cnf(windows中的配置文件为mysql.ini) log-bin=mysql-bin 开启二进制日志 注意：二进制日志必须开启，因为数据的同步实质上就是其他的MySQL数据库服务器将这个数据变更的二进制日志在本机上再执行一遍。 192.168.12.222 为主数据库服务器 192.168.12.223 为从数据库服务器
3.2.1修改主配置文件mysql.cnf
[mysqld] pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock datadir = /var/lib/mysql symbolic-links=0 character-set-server = utf8 #skip-networking innodb_print_all_deadlocks = 1 max_connections = 2000 max_connect_errors = 6000 open_files_limit = 65535 table_open_cache = 128 max_allowed_packet = 4M binlog_cache_size = 1M max_heap_table_size = 8M tmp_table_size = 16M read_buffer_size = 2M read_rnd_buffer_size = 8M sort_buffer_size = 8M join_buffer_size = 28M key_buffer_size = 4M thread_cache_size = 8 query_cache_type = 1 query_cache_size = 8M query_cache_limit = 2M ft_min_word_len = 4 log-bin = mysql-bin server-id = 1 binlog_format = mixed performance_schema = 0 explicit_defaults_for_timestamp #lower_case_table_names = 1 interactive_timeout = 28800 wait_timeout = 28800 #Recommended in standard MySQL setup sql_mode=NO_ENGINE_SUBSTITUTION,NO_AUTO_CREATE_USER,STRICT_TRANS_TABLES [mysqldump] quick max_allowed_packet = 16M [myisamchk] key_buffer_size = 8M sort_buffer_size = 8M read_buffer = 4M write_buffer = 4M
3.2.1.1进入主服务器终端
root@fe842ac59068:/# mysql -uroot -p123456 mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000002 | 337 | | | | +------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
# 配置从数据库用户及权限 mysql> GRANT REPLICATION SLAVE ON *.* to 'ace'@'%' identified by '123456'; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.01 sec)
然后重启mysql容器：docker restart mysql
3.2.2修改从配置文件mysql.cnf
[mysqld] pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock datadir = /var/lib/mysql symbolic-links=0 character-set-server = utf8 #skip-networking innodb_print_all_deadlocks = 1 max_connections = 2000 max_connect_errors = 6000 open_files_limit = 65535 table_open_cache = 128 max_allowed_packet = 4M binlog_cache_size = 1M max_heap_table_size = 8M tmp_table_size = 16M read_buffer_size = 2M read_rnd_buffer_size = 8M sort_buffer_size = 8M join_buffer_size = 28M key_buffer_size = 4M thread_cache_size = 8 query_cache_type = 1 query_cache_size = 8M query_cache_limit = 2M ft_min_word_len = 4 log-bin = mysql-bin server-id = 2 binlog_format = mixed performance_schema = 0 explicit_defaults_for_timestamp #lower_case_table_names = 1 interactive_timeout = 28800 wait_timeout = 28800 #Recommended in standard MySQL setup sql_mode=NO_ENGINE_SUBSTITUTION,NO_AUTO_CREATE_USER,STRICT_TRANS_TABLES [mysqldump] quick max_allowed_packet = 16M [myisamchk] key_buffer_size = 8M sort_buffer_size = 8M read_buffer = 4M write_buffer = 4M
然后重启mysql容器：docker restart mysql
3.2.2.1配置从服务器
[root@k8s-node2 mysql]# docker exec -it mysql bash # 配置主服务器信息 change master to master_host='192.168.12.222',master_user='ace',master_password='123456',master_log_file='mysql-bin.000002',master_log_pos=154;
3.3、从服务器启动I/O 线程和SQL线程
不带任何参数，表示同时启动I/O 线程和SQL线程。 I/O线程从主库读取bin log，并存储到relay log中继日志文件中。 SQL线程读取中继日志，解析后，在从库重放。
mysql> start slave; Query OK, 0 rows affected (0.00 sec)
# Slave_IO_Running: Yes，Slave_SQL_Running: Yes即表示启动成功。 mysql> show slave status\G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.12.223 Master_User: reader Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000002 Read_Master_Log_Pos: 154 Relay_Log_File: 5059a7be072f-relay-bin.000002 Relay_Log_Pos: 320 Relay_Master_Log_File: mysql-bin.000002 Slave_IO_Running: Yes Slave_SQL_Running: Yes
3.4测试
# 主库创建test123库 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | | test123 | +--------------------+ 5 rows in set (0.01 sec) # 从库同步 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | | test123 | +--------------------+ 5 rows in set (0.00 sec)
4、注意事项
1、当配置完成Slave_IO_Running、Slave_SQL_Running不全为YES时，show slave status\G信息中有错误提示，可根据错误提示进行更正。 2、Slave_IO_Running、Slave_SQL_Running不全为YES时，大多数问题都是数据不统一导致。 常见出错点： 1、两台数据库都存在db数据库，而第一台MySQL db中有tab1，第二台MySQL db中没有tab1，那肯定不能成功。 2、已经获取了数据的二进制日志名和位置，又进行了数据操作，导致POS发生变更。在配置CHANGE MASTER时还是用到之前的POS。 3、stop slave后，数据变更，再start slave。出错。 终极更正法：重新执行一遍CHANGE MASTER就好了。
读写分离后续补充。