MySQL5.7 主從同步環境搭建

一、準備環境：(一主一從)

數據庫	ip
主庫	192.168.87.133
從庫	192.168.87.134

 1.1 兩臺虛擬機均安裝MySQL5.7。（mysqladmin --version）

參考：

1. Linux Centos7.5 安裝MySQL5.7
2. mysql 5.7連接不上：Host '192.168.87.1' is not allowed to connect to this MysQL server
3. Mysql--Host 'xxx' is blocked because of many connection errors;unblock with 'mysqladmin flush-hosts'

  1.2成功安裝後，創建兩個數據庫。

數據庫腳本：

(1)創建數據庫
#創建數據庫user_db
CREATE DATABASE `user_db` CHARACTER SET 'utf8mb4' COLLATE 'utf8mb4_general_ci';

(2)在user_db中創建t_user表
DROP TABLE IF EXISTS `t_user`;
CREATE TABLE `t_user` (
`user_id` bigint(20) NOT NULL COMMENT '用戶id',
`fullname` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '用戶姓名',
`user_type` char(1) DEFAULT NULL COMMENT '用戶類型',
PRIMARY KEY (`user_id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

2.配置

 2.1主庫配置：

vim  /etc/my.cnf

注意：（錯誤配置）

網上很多博客是如下這麼配置的。我剛開始也是這麼配置的，配置完畢，重啓mysql是啓動不了。

[mysqld]
#開啓日誌
log‐bin = mysql‐bin
#設置服務id，主從不能一致
server‐id = 1
#設置需要同步的數據庫
binlog‐do‐db=user_db
#屏蔽系統庫同步
binlog‐ignore‐db=mysql
binlog‐ignore‐db=information_schema
binlog‐ignore‐db=performance_schema

提示使用systemctl status mysqld.service和journalctl -xe查看錯誤信息；

並且使用命令：cat /var/log/mysqld.log 查看mysql日誌，會報如下類似錯誤： 

2019-12-25T13:34:26.236167Z 0 [ERROR] unknown variable 'binlog‐do‐db=user_db'
2019-12-25T13:34:26.236192Z 0 [ERROR] Aborting

正確配置（完整配置）：（不是使用-，而改用_）

# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html

[mysqld]

validate_password=off
max_connect_errors=1000
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin

##################主從配置的新增部分
#開啓日誌文件
log_bin=mysql-bin
#設置服務id，主從不能一致
server_id=1
#設置需要同步的數據庫
binlog_do_db=user_db
##屏蔽系統庫同步
binlog_ignore_db=mysql
binlog_ignore_db=information_schema
binlog_ignore_db=performance_schema


# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0                                                      

按照正確配置完後，重啓mysql服務；使用命令：systemctl restart mysqld

 

2.2從庫配置：（完整配置)

[mysqld]

validate_password=off
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin

#開啓日誌
log_bin=mysql‐bin
#設置服務id，主從不能一致
server_id=2
#設置需要同步的數據庫
replicate_wild_do_table=user_db.%
#屏蔽系統庫同步
replicate_wild_ignore_table=mysql.%
replicate_wild_ignore_table=information_schema.%
replicate_wild_ignore_table=performance_schema.%


# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

 按照正確配置完後，重啓mysql服務；使用命令：systemctl restart mysqld

2.3 查看log_bin是否成功開啓 （主、從庫都可查詢下）

3.創建用於複製的用戶（主庫）

#切換至主庫bin目錄，登錄主庫，輸入密碼
mysql ‐uroot ‐p 

#授權主備複製專用賬號
grant replication slave on *.* to 'slave'@'%' identified by '123456';

#刷新權限
FLUSH PRIVILEGES;

#確認位點 記錄下文件名以及位點
show master status;

截圖： （用命令show master status;查出的東西，後面從庫配置需要用到）

4.設置從庫向主庫同步數據、並檢查鏈路

#切換至從庫bin目錄，登錄從庫（輸入密碼）
mysql ‐uroot ‐p

#先停止同步
STOP SLAVE;

#修改從庫指向到主庫，使用上一步記錄的文件名以及位點
CHANGE MASTER TO
master_host = '192.168.87.133',
master_user = 'slave',
master_password = '123456',
master_log_file = 'mysql-bin.000009',
master_log_pos = 582;

#啓動同步
START SLAVE;

#查看從庫狀態Slave_IO_Runing和Slave_SQL_Runing都爲Yes說明同步成功，如果不爲Yes，請檢error_log，#然後排查相關異常。
show slave status\G

######（一般不需要執行）注意： 如果之前此備庫已有主庫指向 需要先執行以下命令清空#########
STOP SLAVE IO_THREAD FOR CHANNEL '';
reset slave all;

ps:

master_host	master主節點:ip地址
master_user	master主節點:主節點創建的用於複製的賬號
master_password	master主節點:主節點創建的用於複製的密碼
master_log_file	master主節點：sql命令show master status查詢出來的file字段的值
master_log_pos	master主節點：sql命令show master status查詢出來的Position字段的值

完整截圖：

ps:查看從庫狀態Slave_IO_Runing和Slave_SQL_Runing都爲Yes說明同步成功，如果不爲Yes，請檢查error_log，然後 排查相關異常。

5.測試：

在主庫（192.168.87.133）中t_user表中插入一條數據；然後刷新從庫t_user表，查看是否同步過來了數據。

5.1主庫：t_user

5.2從庫：t_user （刷新表）