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centos7 mariadb主从复制配置搭建详解步骤

程序员文章站 2022-05-22 15:25:19
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; mar...

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 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!

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。