centos7 mariadb主从复制配置搭建详解步骤

花了小一天的时间,终于实现了centos7 mariadb主从复制配置搭建,下面记录一下过程

环境:

虚拟机:vm8; centos7 版本:7.2.1511; mariadb 版本:centos7.2内置的

主库服务器: 10.69.5.200,CentOS 7,MariaDB 10已安装,有数据。

从库服务器1: 10.69.5.201,CentOS 7,MariaDB 10已安装,无应用数据。

主服务器配置

以下操作在主服务器192.168.71.151的/etc/my.cnf上进行。

1.修改配置文件,命令:vim /etc/my.cnf,输入下列代码:

  [root@localhost ~]# cat /etc/my.cnf  [mysqld]  datadir=/var/lib/mysql  socket=/var/lib/mysql/mysql.sock    `# 新添加的部分  # 配置主从时需要添加以下信息 start  innodb_file_per_table=NO  log-bin=/var/lib/mysql/master-bin #log-bin没指定存储目录,则是默认datadir指向的目录  binlog_format=mixed  server-id=200   #每个服务器都需要添加server_id配置,各个服务器的server_id需要保证唯一性,实践中通常设置为服务器IP地址的最后一位  #配置主从时需要添加以下信息 end   `  # Disabling symbolic-links is recommended to prevent assorted security risks  symbolic-links=0  # Settings user and group are ignored when systemd is used.  # If you need to run mysqld under a different user or group,  # customize your systemd unit file for mariadb according to the  # instructions in http://fedoraproject.org/wiki/Systemd    [mysqld_safe]  log-error=/var/log/mariadb/mariadb.log  pid-file=/var/run/mariadb/mariadb.pid    #  # include all files from the config directory  #  !includedir /etc/my.cnf.d    

最后,:wq!保存退出

2.重启mariadb服务,输入命令

  [root@localhost ~]# systemctl restart mariadb.service

3.登录mariadb

  [root@localhost ~]# mysql -u root -padmin 

注:-p后是密码,中间没有空格

4.创建帐号并赋予replication的权限

从库,从主库复制数据时需要使用这个帐号进行

  MariaDB [(none)]> GRANT REPLICATION SLAVE ON *.* TO 'root'@'10.69.5.%' IDENTIFIED BY 'admin';  Query OK, 0 rows affected (0.00 sec)

5.备份数据库数据,用于导入到从数据库中

加锁

实际工作中,备份的时候是不让往库中写数据的,所以数据库要加锁,只能读

  MariaDB [(none)]> FLUSH TABLES WITH READ LOCK;  Query OK, 0 rows affected (0.00 sec)

记录主库log文件及其当前位置

  MariaDB [(none)]> SHOW MASTER STATUS;  +------------------+----------+--------------+------------------+  | File       | Position | Binlog_Do_DB | Binlog_Ignore_DB |  +------------------+----------+--------------+------------------+  | mysql-bin.000001 |   694 |       |         |  +------------------+----------+--------------+------------------+

记住File和Position的部分,从服务器会用到

备份数据,输入命令:

  [root@localhost ~]# mysqldump -uroot -p --all-databases > /root/db.sql

解锁 主库

数据备份完成后,就可以释放主库上的锁:

  MariaDB [(none)]> UNLOCK TABLES;  Query OK, 0 rows affected (0.00 sec)

从服务器配置

以下在从服务器上的操作

1.导入主库的数据

  [root@localhost ~]# mysql -uroot -p < db.sql

2.从服务器/etc/my.cnf配置,设置relay-log

my.cnf文件中添加一行relay_log=relay-bin

如果不设置,默认是按主机名 + “-relay-bin”生成relay log。

  [root@localhost ~]# cat /etc/my.cnf  [mysqld]  datadir=/var/lib/mysql  socket=/var/lib/mysql/mysql.sock  # Disabling symbolic-links is recommended to prevent assorted security risks  symbolic-links=0    `#配置主从时需要添加以下信息 start  innodb_file_per_table=NO  server-id=201 #一般与服务器ip的最后数字一致  relay-log=/var/lib/mysql/relay-bin  #配置主从时需要添加以下信息 end   `  # Settings user and group are ignored when systemd is used.  # If you need to run mysqld under a different user or group,  # customize your systemd unit file for mariadb according to the  # instructions in http://fedoraproject.org/wiki/Systemd    [mysqld_safe]  log-error=/var/log/mariadb/mariadb.log  pid-file=/var/run/mariadb/mariadb.pid    #  # include all files from the config directory  #  !includedir /etc/my.cnf.d    

3.重启服务

  [root@localhost ~]# systemctl restart mariadb.service

4.登录mariadb

  [root@localhost ~]# mysql -u root -padmin

5.设置主从复制

  MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='10.69.5.200',MASTER_USER='root', MASTER_PASSWORD='admin', MASTER_LOG_FILE='master-bin.000001', MASTER_LOG_POS= 694;  Query OK, 0 rows affected (0.02 sec)

这个命令完成以下几个任务:

a.设置当前服务器为主服务器(10.69.5.200)的从库

b.提供当前数据库(从库)从主库复制数据时所需的用户名和密码,即上面的GRANT REPLICATION SLAVE ON *.* TO IDENTIFIED BY 'admin';设置的

c.指定从库开始复制主库时需要使用的日志文件和文件位置,即上面主库执行SHOW MASTER STATUS;显示结果中的File和Position

6.开启主从复制

  MariaDB [(none)]> START SLAVE;  Query OK, 0 rows affected (0.00 sec)  

7.查看从库状态

  MariaDB [(none)]> show slave statusG  *************************** 1. row ***************************          Slave_IO_State: Waiting for master to send event           Master_Host: 10.69.5.200           Master_User: root           Master_Port: 3306          Connect_Retry: 60         Master_Log_File: master-bin.000001       Read_Master_Log_Pos: 694          Relay_Log_File: relay-bin.000003          Relay_Log_Pos: 530      Relay_Master_Log_File: master-bin.000001         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:             Last_Errno: 0            Last_Error:            Skip_Counter: 0       Exec_Master_Log_Pos: 694         Relay_Log_Space: 818         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: 0  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: 200  1 row in set (0.00 sec)  

注意:结果中Slave_IO_Running和Slave_SQL_Running必须为Yes,如果不是,需要根据提示的错误修改。

验证

主服务器:

  MariaDB [(none)]> show databases;  +--------------------+  | Database      |  +--------------------+  | information_schema |  | mysql       |  | mytest       |  | performance_schema |  | test        |  +--------------------+  5 rows in set (0.04 sec)    MariaDB [(none)]> use mytest;  Reading table information for completion of table and column names  You can turn off this feature to get a quicker startup with -A    Database changed  MariaDB [mytest]> select * from user;  +----+------+  | id | name |  +----+------+  | 1 | t  |  | 2 | t2  |  | 3 | t3  |  +----+------+  3 rows in set (0.00 sec)    MariaDB [mytest]> insert into user(name) values('t4');  Query OK, 1 row affected (0.01 sec)    MariaDB [mytest]> select * from user;  +----+------+  | id | name |  +----+------+  | 1 | t  |  | 2 | t2  |  | 3 | t3  |  | 4 | t4  |  +----+------+  4 rows in set (0.00 sec)    

查看从服务器数据是否变化:

  MariaDB [(none)]> use mytest;  Reading table information for completion of table and column names  You can turn off this feature to get a quicker startup with -A    Database changed  MariaDB [mytest]> select * from user;  +----+------+  | id | name |  +----+------+  | 1 | t  |  | 2 | t2  |  +----+------+  2 rows in set (0.00 sec)    MariaDB [mytest]> select * from user;  +----+------+  | id | name |  +----+------+  | 1 | t  |  | 2 | t2  |  | 4 | t4  |  +----+------+  3 rows in set (0.00 sec)    

可以看到,从服务器更新了数据

搭建过程中遇到的问题及解决方法

问题1:从服务器设置主从复制出现错误:

  MariaDB [mytest]> start slave;  ERROR 1201 (HY000): Could not initialize master info structure; more error messages can be found in the MariaDB error log

发现 

  Slave_IO_Running: No  Slave_SQL_Running: No

进一步发现我输入的是:CHANGE MASTER TO MASTER_HOST='192.168.71.151',MASTER_USER='slave_user', MASTER_PASSWORD='bigs3cret', MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS= 469;

重新输入:MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='10.69.5.200',MASTER_USER='root', MASTER_PASSWORD='admin', MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS= 469;
报错:ERROR 1201 (HY000): Could not initialize master info structure; more error messages can be found in the MariaDB error log

于是看错误日志:/var/log/mariadb/mariadb.log

错误日志的位置在/etc/my.cnf中配置:log-error=/

  [root@localhost ~]# cat /var/log/mariadb/mariadb.log  160915 12:52:02 [ERROR] Failed to open the relay log './mariadb-relay-bin.000001' (relay_log_pos 4)  160915 12:52:02 [ERROR] Could not find target log during relay log initialization  

通过查找答案: 删除/var/lib/mysql/路径下the ‘master.info' ‘mysqld-relay-bin.*' ‘relay-log.info' ‘relay-log-index.*'

运行命令:rm -rf master.info,rm -rf *relay*

重启服务:[root@localhost mysql]# systemctl restart mariadb.service

进入mariadb:

  [root@localhost mysql]# mysql -u root -padmin    MariaDB [(none)]> flush logs;  Query OK, 0 rows affected (0.00 sec)    MariaDB [(none)]> reset slave;  Query OK, 0 rows affected (0.00 sec)    

重新设置主从复制关系:

  MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='10.69.5.200',MASTER_USER='root', MASTER_PASSWORD='admin', MASTER_LOG_FILE='master-bin.000001', MASTER_LOG_POS= 694;  Query OK, 0 rows affected (0.02 sec)  

这次成功了。

  MariaDB [(none)]> start slave;  Query OK, 0 rows affected (0.01 sec)

查看从库状态:

  MariaDB [(none)]> show slave statusG  *************************** 1. row ***************************          Slave_IO_State: Connecting to master           Master_Host: 10.69.5.200           Master_User: root           Master_Port: 3306          Connect_Retry: 60         Master_Log_File: master-bin.000001       Read_Master_Log_Pos: 694          Relay_Log_File: relay-bin.000001          Relay_Log_Pos: 4      Relay_Master_Log_File: master-bin.000001        Slave_IO_Running: Connecting        Slave_SQL_Running: Yes    ・・・    ・・・    ・・・   Replicate_Ignore_Server_Ids:          Master_Server_Id: 0  1 row in set (0.00 sec)  

发现问题2.Slave_IO_Running: Connecting

问题2.Slave_IO_Running: Connecting

查看错误日志

  [root@localhost ~]# cat /var/log/mariadb/mariadb.log  ・・・  160915 13:17:56 [Note] Slave SQL thread initialized, starting replication in log 'master-bin.000001' at position 694, relay log '/var/lib/mysql/relay-bin.000001' position: 4  160915 13:17:56 [ERROR] Slave I/O: error connecting to master 'root@10.69.5.200:3306' - retry-time: 60 retries: 86400 message: Can't connect to MySQL server on '10.69.5.200' (113), Error_code: 2003    

这时运行telnet命令

  [root@localhost ~]# telnet 10.69.5.200 3306

-bash: telnet: 未找到命令

安装telnet

  [root@localhost ~]# yum -y install telnet-server.x86_64  

安装成功后重启telnet服务

  [root@localhost ~]# systemctl start telnet.socket  [root@localhost ~]# systemctl enable telnet.socket  [root@localhost ~]# telnet 10.69.5.200 3306

-bash: telnet: 未找到命令

还是不行

这回我reboot重启虚拟机,运行命令

注意:这回不是"yum -y install telnet-server.x86_64"了,这回没有telnet-server了

  [root@localhost ~]# yum install telnet.x86_64

运行成功了

接着

  [root@localhost ~]# systemctl enable telnet.socket  [root@localhost ~]# systemctl start telnet.socket  [root@localhost ~]# firewall-cmd --add-service=telnet --permanent   success  [root@localhost ~]# telnet  telnet>  

telnet终于安装成功了

从最新版本的centos7系统开始,默认的是 Mariadb而不是mysql!

使用系统自带的repos安装很简单:

  yum install mariadb mariadb-server

  • systemctl start mariadb ==> 启动mariadb
  • systemctl enable mariadb ==> 开机自启动
  • mysql_secure_installation ==> 设置 root密码等相关
  • mysql -u root -p 123456 ==> 测试登录!

结束!

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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