基于docker的mysql8的主从复制

创建mysql的docker镜像

  • 构建docker镜像，其中数据卷配置内容在下面,结构目录如下

    mysql

    version: '3.7'
services: 
    db:
      # images 8.x
      image: mysql
      restart: always
      environment: 
        MYSQL_ROOT_PASSWORD: 456123
      command: 
        --default-authentication-plugin=mysql_native_password
        --character-set-server=utf8mb4
        --collation-server=utf8mb4_general_ci
        --explicit_defaults_for_timestamp=true
        --lower_case_table_names=1
      ports: 
        - 3309:3306
      volumes: 
        - ./data:/var/lib/mysql
        - ./my.cnf:/etc/my.cnf

配置mysql的主库

  • 更新配置文件

    # Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

#
# The MySQL  Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html

[mysqld]

pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

# Custom config should go here
# [必须]启用二进制日志
log-bin=mysql-bin 
# [必须]服务器唯一ID，默认是1  1~255
server-id=1 
sql_mode=STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION

  • 配置操作

    1. 启动mysql

      docker-compose up -d

    2. 更新配置

      • 查看容器

        docker ps

        docker ps

        • 进入mysql交互

           docker exec -it 518a92715f6f /bin/bash

        • 登录mysql

           mysql -u root -p

        • 配置

          #在主库上创建同步用户并授权
CREATE USER 'replicate'@'112.74.41.236' IDENTIFIED BY '123456';
GRANT REPLICATION SLAVE ON *.* TO 'replicate'@'112.74.41.236';
FLUSH PRIVILEGES;
#最后增加远程访问用户 并赋予所有权限，远程访问测试用
CREATE USER antsdouble IDENTIFIED BY '123456';
GRANT ALL ON *.* TO 'antsdouble'@'%';
#用navicate12及以上可以不用修复修复远程登录报报 caching_sha2_password异常
# mysql8 用新的驱动  driver-class-name: com.mysql.cj.jdbc.Driver
ALTER USER 'antsdouble'@'%' IDENTIFIED BY '123456' PASSWORD EXPIRE NEVER;
ALTER USER 'antsdouble'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
FLUSH PRIVILEGES;
#查询master的状态，此处File，Position数据在配置从库时用到
show master status;

  • 相关说明

    1. server-id是唯一的，主从不能相同，server-id为1表示mysq数据库为主数据库，server-id为2表示mysql的数据库为从数据库

    2. 为何必须挂载到/etc/my.cnf 文件上，而不是/etc/mysql/my.cnf 文件上？因为mysql默认配置文件位置在/etc/mysql/my.cnf，挂在方式无法改变容器中文件内容，my.conf内容不会改变，my.cnf中没有我们自定义的配置内容，启动mysql容器会报错

      lower_case_table_names：忽略表名、列名等数据结构的大小写（注意：不是每行记录内容的大小写！）。


log-bin：开启二进制记录。这是为了主从复制而做的设置。本文使用RBR（Row-Based Replication）模式。

slow_query_log=1：开启慢查询日志。如果某一条SQL执行的时间超过long_query_time设置的秒数，那么就记录下来。记录文件路径可以使用show variables;命令，在变量名是slow_query_log_file下查找到具体的日志文件路径。

long_query_time=1：单位是秒。指如果某一条SQL语句执行时间超过1秒，就记录下来。必须开启慢查询日志了以后，此变量才能使用。

log_error：开启错误日志。show variables like 'log_error'; 就可以查询到日志文件的路径。mysql的docker官方镜像如果设置别的取值会导致容器无法正常启动。

配置mysql的从库

  • 更新配置文件

    # Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

#
# The MySQL  Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html

[mysqld]

pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

# Custom config should go here
# [必须]启用二进制日志
log-bin=mysql-bin 
# [必须]服务器唯一ID，默认是1
server-id=1 
sql_mode=STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION

  • 配置操作

    1. 进入交互模式，方法同主库

    2. 配置从库

      change master to master_host='112.74.41.236',master_port=3309,master_user='replicate',master_password='123456',master_log_file='binlog.000006',master_log_pos=3862;

      • 说明

        master_port：Master的端口号，指的是容器的端口号

master_user：用于数据同步的用户

master_password：用于同步的用户的密码

master_log_file：指定 Slave 从哪个日志文件开始复制数据，即上文中提到的 File 字段的值

master_log_pos：从哪个 Position 开始读，即上文中提到的 Position 字段的值

master_connect_retry：如果连接失败，重试的时间间隔，单位是秒，默认是60秒

    3. 查看

      show slave status\G
# 查询slave的状态，Slave_IO_Running及Slave_SQL_Running进程必须正常运行，即YES状态，否则都是错误的状态 错误可以在2标记处查看到原因，也可以通过
show slave status;

测试功能

  • 主库添加一条数
  • 在从库查看

常见问题

  • 可能产生的原因

    网络不通

检查ip,端口

密码不对

检查是否创建用于同步的用户和用户密码是否正确

pos不对

检查Master的 Position

  • Could not execute Update_rows event on table oa.bui_bill_sum; Can’t find record in ‘bui_bill_sum’, Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event’s master log mysql-bin.000138, end_log_pos 160051747

    1. 解决，临时

      进入sql 执行
STOP SLAVE; 
SET GLOBAL sql_slave_skip_counter =1; #表示跳过一步错误，后面的数字可变 
START SLAVE;

    2. 永久

      在my.cnf中配置
slave-skip-errors = 1032 就会跳过所有的1032的错误,多个用逗号分隔

  • mysql并没有从my.cnf文件中更新server_id，既然这样就只能手动修改了

set global server_id=2; #此处的数值和my.cnf里设置的一样就行
slave start;

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