本文正在参与「技能专题19期 闲谈数据库技能」活动

一、环境规划

hostname	IP地址	系统版别	角色
master	192.168.3.171	centos 7.6	主节点
node01	192.168.3.172	centos 7.6	从节点
node02	192.168.3.173	centos 7.6	从节点

二、Mariadb的主从仿制介绍

1.主从仿制简介

主从同步使得数据能够从一个数据库服务器仿制到其他服务器上，在仿制数据时，一个服务器充任主服务器（master），其他的服务器充任从服务器（slave）。

2.半同步仿制介绍

半同步仿制是解决主库数据挂掉，从库数据不一致的问题。 解决方法：半同步仿制，半同步仿制场景中，master会监视一切的slave，保证其中至少一台数据完全同步成功，master才会回来客户端信息，此数据写成功。

3.主从仿制原理图

三、装置Mariadb

1.装备yum库房

3个节点都装置Mariadb数据库

[root@master yum.repos.d]# cat mariadb.repo 
# MariaDB 10.6 CentOS repository list - created 2021-12-27 11:21 UTC
# https://mariadb.org/download/
[mariadb]
name = MariaDB
baseurl = https://mirrors.ustc.edu.cn/mariadb/yum/10.6/centos7-amd64
gpgkey=https://mirrors.ustc.edu.cn/mariadb/yum/RPM-GPG-KEY-MariaDB
gpgcheck=0

 sed -i 's#//mirrors.xtom.com.hk#//mirrors.ustc.edu.cn#g' /etc/yum.repos.d/mariadb.repo

2.检查yum库房

[root@master yum.repos.d]# yum repolist all
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
repo id                                                              repo name                                                             status
mariadb                                                              MariaDB                                                               enabled: 96
repolist: 96

3.装置mariadb

yum -y install mariadb-server

4.发动mariadb服务

[root@master yum.repos.d]# systemctl start mariadb
[root@master yum.repos.d]# systemctl enable  mariadb
Created symlink from /etc/systemd/system/multi-user.target.wants/mariadb.service to /usr/lib/systemd/system/mariadb.service.
[root@master yum.repos.d]# 

5.从节点装置mariadb

如上步骤装置即可。

四、mariadb主库装备

1.mariadb的初始化

[root@master ~]# mariadb-secure-installation 
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!
In order to log into MariaDB to secure it, we'll need the current
password for the root user. If you've just installed MariaDB, and
haven't set the root password yet, you should just press enter here.
Enter current password for root (enter for none): 
OK, successfully used password, moving on...
Setting the root password or using the unix_socket ensures that nobody
can log into the MariaDB root user without the proper authorisation.
You already have your root account protected, so you can safely answer 'n'.
Switch to unix_socket authentication [Y/n] n
 ... skipping.
You already have your root account protected, so you can safely answer 'n'.
Change the root password? [Y/n] n
 ... skipping.
By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] y
 ... Success!
Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] n
 ... skipping.
By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] y
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] y
 ... Success!
Cleaning up...
All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.
Thanks for using MariaDB!
[root@master ~]# 

2.修正主库装备文件

[root@master ~]# grep -Ev "^$|^#" /etc/my.cnf.d/server.cnf
[server]
[mysqld]
character-set-server=utf8
collation-server=utf8_general_ci
server_id = 12    #  一组主从组里的每个id必须是唯一值。引荐用ip位数
log-bin= mysql-bin # 二进制日志，后面指定寄存方位。假如仅仅指定名字，默许寄存在/var/lib/mysql下
lower_case_table_names=1 # 不区别大小写
binlog-format=ROW    # 二进制日志文件格局
log-slave-updates=True    # slave更新是否记入日志
sync-master-info=1    # 值为1保证信息不会丢掉
slave-parallel-threads=3 #一起发动多少个仿制线程，最多与要仿制的数据库数量相等即可
binlog-checksum=CRC32    # 效验码
master-verify-checksum=1    # 发动主服务器效验
slave-sql-verify-checksum=1   # 发动从服务器效验
[galera]
[embedded]
[mariadb]
[mariadb-10.6]
[root@master ~]# 

3.重启mariadb服务

[root@master ~]# systemctl restart mariadb
[root@master ~]# 

五、mariadb从库装备

1.修正从库node01节点的server.cnf文件

[root@node01 ~]# cat  /etc/my.cnf.d/server.cnf
#
# These groups are read by MariaDB server.
# Use it for options that only the server (but not clients) should see
#
# See the examples of server my.cnf files in /usr/share/mysql/
#
# this is read by the standalone daemon and embedded servers
[server]
# this is only for the mysqld standalone daemon
[mysqld]
character-set-server=utf8
collation-server=utf8_general_ci
server_id=15
#log-bin= mysql-bin #log-bin是二进制文件
relay_log = relay-bin    # 中继日志, 后面指定寄存方位。假如仅仅指定名字，默许寄存在/var/lib/mysql下
lower_case_table_names=1
#
# * Galera-related settings
#
[galera]
# Mandatory settings
#wsrep_on=ON
#wsrep_provider=
#wsrep_cluster_address=
#binlog_format=row
#default_storage_engine=InnoDB
#innodb_autoinc_lock_mode=2
#
# Allow server to accept connections on all interfaces.
#
#bind-address=0.0.0.0
#
# Optional setting
#wsrep_slave_threads=1
#innodb_flush_log_at_trx_commit=0
# this is only for embedded server
[embedded]
# This group is only read by MariaDB servers, not by MySQL.
# If you use the same .cnf file for MySQL and MariaDB,
# you can put MariaDB-only options here
[mariadb]
# This group is only read by MariaDB-10.6 servers.
# If you use the same .cnf file for MariaDB of different versions,
# use this group for options that older servers don't understand
[mariadb-10.6]

2.修正从库node02节点的server.cnf文件

[root@node02 ~]# cat  /etc/my.cnf.d/server.cnf
#
# These groups are read by MariaDB server.
# Use it for options that only the server (but not clients) should see
#
# See the examples of server my.cnf files in /usr/share/mysql/
#
# this is read by the standalone daemon and embedded servers
[server]
# this is only for the mysqld standalone daemon
[mysqld]
character-set-server=utf8
collation-server=utf8_general_ci
server_id=16
#log-bin= mysql-bin #log-bin是二进制文件
relay_log = relay-bin    # 中继日志, 后面指定寄存方位。假如仅仅指定名字，默许寄存在/var/lib/mysql下
lower_case_table_names=1
#
# * Galera-related settings
#
[galera]
# Mandatory settings
#wsrep_on=ON
#wsrep_provider=
#wsrep_cluster_address=
#binlog_format=row
#default_storage_engine=InnoDB
#innodb_autoinc_lock_mode=2
#
# Allow server to accept connections on all interfaces.
#
#bind-address=0.0.0.0
#
# Optional setting
#wsrep_slave_threads=1
#innodb_flush_log_at_trx_commit=0
# this is only for embedded server
[embedded]
# This group is only read by MariaDB servers, not by MySQL.
# If you use the same .cnf file for MySQL and MariaDB,
# you can put MariaDB-only options here
[mariadb]
# This group is only read by MariaDB-10.6 servers.
# If you use the same .cnf file for MariaDB of different versions,
# use this group for options that older servers don't understand
[mariadb-10.6]

3.重启node01和node02的mariadb服务

systemctl restart mariadb

六、检查mariadb主库状况

1.创立数据库用户

MariaDB [(none)]>  grant replication slave, replication client on *.* to 'redhat'@'%'  identified by 'admin';
Query OK, 0 rows affected (0.025 sec)
MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.000 sec)

2.检查数据库用户信息

MariaDB [(none)]> select user,password,host from mysql.user;
+-------------+-------------------------------------------+-----------+
| User        | Password                                  | Host      |
+-------------+-------------------------------------------+-----------+
| mariadb.sys |                                           | localhost |
| root        | invalid                                   | localhost |
| mysql       | invalid                                   | localhost |
| redhat      | *4ACFE3202A5FF5CF467898FC58AAB1D615029441 | %         |
+-------------+-------------------------------------------+-----------+
4 rows in set (0.002 sec)
MariaDB [(none)]> 

3.检查主库状况

MariaDB [(none)]> show master status;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000002 |      659 |              |                  |
+------------------+----------+--------------+------------------+
1 row in set (0.000 sec)
MariaDB [(none)]> 

4.检查mysql-bin日志文件

[root@master ~]#  ll /var/lib/mysql/mysql-bin.index 
-rw-rw----. 1 mysql mysql 38 Nov 23 23:31 /var/lib/mysql/mysql-bin.index
[root@master ~]# cat  /var/lib/mysql/mysql-bin.index 
./mysql-bin.000001
./mysql-bin.000002

5.gtid查询

MariaDB [(none)]> select binlog_gtid_pos('mysql-bin.000002',659);
+-----------------------------------------+
| binlog_gtid_pos('mysql-bin.000002',659) |
+-----------------------------------------+
| 0-12-2                                  |
+-----------------------------------------+
1 row in set (0.000 sec)
MariaDB [(none)]> 

七、发动从库

1.从库设置主库的gtid

MariaDB [(none)]>  set global gtid_slave_pos='0-12-2';
Query OK, 0 rows affected (0.080 sec)

2.连接主库

MariaDB [(none)]>  change master to master_host='192.168.3.171',master_user='redhat',master_password='admin',master_use_gtid=slave_pos;
Query OK, 0 rows affected (0.182 sec)

3.发动从库

MariaDB [(none)]>  start slave;
Query OK, 0 rows affected (0.123 sec)

4.查询从库状况

MariaDB [(none)]> show  slave status\G
*************************** 1. row ***************************
                Slave_IO_State: Waiting for master to send event
                   Master_Host: 192.168.3.171
                   Master_User: redhat
                   Master_Port: 3306
                 Connect_Retry: 60
               Master_Log_File: mysql-bin.000002
           Read_Master_Log_Pos: 1450
                Relay_Log_File: relay-bin.000002
                 Relay_Log_Pos: 1461
         Relay_Master_Log_File: mysql-bin.000002
              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: 1450
               Relay_Log_Space: 1764
               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: 12
                Master_SSL_Crl: 
            Master_SSL_Crlpath: 
                    Using_Gtid: Slave_Pos
                   Gtid_IO_Pos: 0-12-7
       Replicate_Do_Domain_Ids: 
   Replicate_Ignore_Domain_Ids: 
                 Parallel_Mode: optimistic
                     SQL_Delay: 0
           SQL_Remaining_Delay: NULL
       Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
              Slave_DDL_Groups: 3
Slave_Non_Transactional_Groups: 2
    Slave_Transactional_Groups: 0
1 row in set (0.000 sec)
MariaDB [(none)]> 

八、测试主从同步

1.主库写入数据

MariaDB [(none)]> create database school;
Query OK, 1 row affected (0.001 sec)
MariaDB [(none)]> use school;
Database changed
MariaDB [school]> CREATE TABLE IF NOT EXISTS `student`(
    ->    `id` INT UNSIGNED AUTO_INCREMENT,
    ->    `name` VARCHAR(100) NOT NULL,
    ->    `gender` TINYINT NOT NULL,
    ->    `age` INT UNSIGNED,
    ->    `class` INT UNSIGNED,
    ->      `course` VARCHAR(100) NOT NULL,
    ->     `grade` INT UNSIGNED,
    ->    PRIMARY KEY ( `id` )
    -> )ENGINE=InnoDB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.206 sec)
MariaDB [school]> insert into student ( name, gender, age, class, Course, grade ) values ( "顶峰", "0", "22", "4", "英语", "100"), ( "陈林", "1", "15", "5", "化学", "99" );
Query OK, 2 rows affected (0.012 sec)
Records: 2  Duplicates: 0  Warnings: 0
MariaDB [school]> insert into student ( name, gender, age, class, course, grade ) values  ( "王明", "0", "16", "2", "数学", "88"),  ( "万易", "0", "17", "4", "地舆", "79" ), ( "李依依", "1", "17", "3", "语文",  "90"  ) ;
Query OK, 3 rows affected (0.017 sec)
Records: 3  Duplicates: 0  Warnings: 0

2.主库检查数据表

MariaDB [school]> select * from school.student;
+----+-----------+--------+------+-------+--------+-------+
| id | name      | gender | age  | class | course | grade |
+----+-----------+--------+------+-------+--------+-------+
|  1 | 顶峰      |      0 |   22 |     4 | 英语   |   100 |
|  2 | 陈林      |      1 |   15 |     5 | 化学   |    99 |
|  3 | 王明      |      0 |   16 |     2 | 数学   |    88 |
|  4 | 万易      |      0 |   17 |     4 | 地舆   |    79 |
|  5 | 李依依    |      1 |   17 |     3 | 语文   |    90 |
+----+-----------+--------+------+-------+--------+-------+
5 rows in set (0.000 sec)
MariaDB [school]> 

3.从库检查数据表

[root@node01 ~]# hostname
node01
[root@node01 ~]# mariadb
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 12
Server version: 10.6.11-MariaDB MariaDB Server
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> select * from school.student;
+----+-----------+--------+------+-------+--------+-------+
| id | name      | gender | age  | class | course | grade |
+----+-----------+--------+------+-------+--------+-------+
|  1 | 顶峰      |      0 |   22 |     4 | 英语   |   100 |
|  2 | 陈林      |      1 |   15 |     5 | 化学   |    99 |
|  3 | 王明      |      0 |   16 |     2 | 数学   |    88 |
|  4 | 万易      |      0 |   17 |     4 | 地舆   |    79 |
|  5 | 李依依    |      1 |   17 |     3 | 语文   |    90 |
+----+-----------+--------+------+-------+--------+-------+
5 rows in set (0.000 sec)
MariaDB [(none)]> 

本文正在参与「技能专题19期 闲谈数据库技能」活动