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centos7 mariadb主从复制配置搭建

时间:2017-01-22 13:59来源:linux.it.net.cn 作者:IT

centos7 mariadb主从复制配置搭建

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 'root'@'10.69.5.%' 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 status\G
*************************** 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 status\G
*************************** 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！

搭建centos7 mariadb主从复制配置参考资料  http://ourmysql.com/archives/1370 http://joelhy.github.io/2015/02/06/mariadb-master-slave-replication/ http://www.voidcn.com/blog/c571121319/article/p-1554892.html

解决问题参考资料：  问题1：  http://www.slickdev.com/2008/10/20/mysql-slave-failed-to-open-the-relay-log/  http://bbs.chinaunix.net/thread-1349827-1-1.html http://dev.nuclearrooster.com/2009/03/06/relay-log-issues-when-starting-mysql-replication-slave/  问题2：  yum install telnet-server  systemctl enable telnet.socket  systemctl start telnet.socket  firewall-cmd –add-service=telnet –permanent

http://www.cnblogs.com/hellotracy/articles/5143960.html

“`

参考：  http://joelhy.github.io/2015/02/06/mariadb-master-slave-replication/ http://www.voidcn.com/blog/c571121319/article/p-1554892.html http://www.cnblogs.com/hellotracy/articles/5143960.html

(责任编辑：IT)
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