mysql多实例部署和传统主从

1. 主从简介

在现代企业中，数据显得尤为重要，而存储数据的数据库选择又五花八门，但无论是何种数据库，均存在着一种隐患。

想几个问题：

• 用一台数据库存放数据，若此数据库服务器宕机了导致数据丢失怎么办？
• 业务量大了，数据多了，访问的人多了，一台数据库无法保证服务质量了怎么办？

1.1 主从作用

• 实时灾备，用于故障切换
• 读写分离，提供查询服务
• 备份，避免影响业务

1.2 主从形式

• 一主一从
• 主主复制
• 一主多从---扩展系统读取的性能，因为读是在从库读取的
• 多主一从---5.7开始支持
• 联级复制

2. 主从复制原理

主从复制步骤：

• 主库将所有的写操作记录到binlog日志中并生成一个log dump线程，将binlog日志传给从库的I/O线程
• 从库生成两个线程，一个I/O线程，一个SQL线程
  • I/O线程去请求主库的binlog，并将得到的binlog日志写到relay log（中继日志） 文件中
  • SQL线程，会读取relay log文件中的日志，并解析成具体操作，来实现主从的操作一致，达到最终数据一致的目的

3. 主从复制配置

主从复制配置步骤：

1. 确保从数据库与主数据库里的数据一样
2. 在主数据库里创建一个同步账号授权给从数据库使用
3. 配置主数据库（修改配置文件）
4. 配置从数据库（修改配置文件）

需求：
搭建两台MySQL服务器，一台作为主服务器，一台作为从服务器，主服务器进行写操作，从服务器进行读操作

环境说明：

3.1 mysql安装

分别在主从两台服务器上安装mysql-5.7版本，此处略过安装步骤，若有疑问请参考《mysql基础》与《mysql进阶》两篇文章。

3.2 mysql主从配置

3.2.1 确保从数据库与主数据库里的数据一样

为确保从数据库与主数据库里的数据一样，先全备主数据库并还原到从数据库中

//先查看主库有哪些库
[root@localhost ~]# mysql -uroot -pruntime123！ -e 'show databases;'
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| student            |
| sys                |
| teacher            |
+--------------------+

//再查看从库有哪些库
[root@localhost ~]# mysql -uroot -pruntime123！ -e 'show databases;'
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+

//全备主库

mysql> FLUSH TABLES WITH READ LOCK;
Query OK, 0 rows affected (0.00 sec)

//备份主库并将备份文件传送到从库
[root@localhost ~]# mysqldump -uroot -pruntime123！ --all-databases > /opt/all-201808191200.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
[root@localhost ~]# ls /opt/
all-201808191200.sql
[root@localhost ~]# scp /opt/all-201808191200.sql root@172.16.12.129:/opt/
root@172.16.12.129's password:
all-201808191200.sql                              100%  786KB  10.6MB/s   00:00 

//解除主库的锁表状态，直接退出交互式界面即可
mysql> quit
Bye


//在从库上恢复主库的备份并查看从库有哪些库，确保与主库一致
[root@localhost ~]# mysql -uroot -pruntime123！ < /opt/all-201808191200.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@localhost ~]# mysql -uroot -pruntime123！ -e 'show databases;'
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| student            |
| sys                |
| teacher            |
+--------------------+

3.2.2 在主数据库里创建一个同步账号授权给从数据库使用

mysql> CREATE USER 'repl'@'172.16.12.129' IDENTIFIED BY 'repl123';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'172.16.12.129';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

3.2.3 配置主数据库

[root@localhost ~]# vim /etc/my.cnf
//在[mysqld]这段的后面加上如下内容
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-bin=mysql-bin   //启用binlog日志
server-id=1     //数据库服务器唯一标识符，主库的server-id值必须比从库的大

symbolic-links=0

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


//重启mysql服务
[root@localhost ~]# systemctl restart mysqld
[root@localhost ~]# ss -antl
State       Recv-Q Send-Q      Local Address:Port                     Peer Address:Port
LISTEN      0      128                     *:22                                  *:*
LISTEN      0      100             127.0.0.1:25                                  *:*
LISTEN      0      128                    :::22                                 :::*
LISTEN      0      100                   ::1:25                                 :::*
LISTEN      0      80                     :::3306                               :::* 


//查看主库的状态
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 |      154 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.01 sec)

3.2.4 配置从数据库

[root@localhost ~]# vim /etc/my.cnf
//添加如下内容
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
server-id=2     //设置从库的唯一标识符，从库的server-id值必须小于主库的该值
relay-log=mysql-relay-bin       //启用中继日志relay-log

symbolic-links=0

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


//重启从库的mysql服务
[root@localhost ~]# systemctl restart mysqld
[root@localhost ~]# ss -antl
State      Recv-Q Send-Q           Local Address:Port                          Peer Address:Port
LISTEN     0      128                          *:22                                       *:*
LISTEN     0      100                  127.0.0.1:25                                       *:*
LISTEN     0      128                         :::22                                      :::*
LISTEN     0      100                        ::1:25                                      :::*
LISTEN     0      80                          :::3306                                    :::*




//配置并启动主从复制
mysql> CHANGE MASTER TO
    -> MASTER_HOST='172.16.12.128',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='repl123',
    -> MASTER_LOG_FILE='mysql-bin.000001',
    -> MASTER_LOG_POS=154;
Query OK, 0 rows affected, 2 warnings (0.33 sec)

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)


//查看从服务器状态
mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.16.12.128
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 154
               Relay_Log_File: mysql-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes      //此处必须为Yes
            Slave_SQL_Running: Yes      //此处必须为Yes
              Replicate_Do_DB:
          Replicate_Ignore_DB:  

3.2.5 测试验证

在主服务器的student库的bj2表中插入数据：

mysql> select * from bj2;
Empty set (0.00 sec)

mysql> insert into bj2 values (1,'sean',20),(2,'tom',23),(3,'jerry',30);
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from bj2;
+----+-------+------+
| id | name  | age  |
+----+-------+------+
|  1 | sean  |   20 |
|  2 | tom   |   23 |
|  3 | jerry |   30 |
+----+-------+------+
3 rows in set (0.00 sec)

在从数据库中查看数据是否同步：

mysql> use student;
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
mysql> select * from bj2;
+----+-------+------+
| id | name  | age  |
+----+-------+------+
|  1 | sean  |   20 |
|  2 | tom   |   23 |
|  3 | jerry |   30 |
+----+-------+------+
3 rows in set (0.00 sec)

mysql多实例部署

用户和组并解压下本地配置程序至/usr/

//创建用户和组
[root@localhost src]# groupadd -r mysql
[root@localhost src]# useradd -M -s /sbin/nologin -g mysql mysql


//解压软件至/usr/local/
[root@localhost src]# ls
debug  kernels  mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz
[root@localhost src]# tar xf mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz -C /usr/local/
[root@localhost ~]# ls /usr/local/
bin  games    lib    libexec                              sbin   src
etc  include  lib64  mysql-5.7.22-linux-glibc2.12-x86_64  share
[root@localhost ~]# cd /usr/local/
[root@localhost local]# ln -sv mysql-5.7.22-linux-glibc2.12-x86_64/ mysql
‘mysql’ -> ‘mysql-5.7.22-linux-glibc2.12-x86_64/’
[root@localhost local]# ll
total 0
drwxr-xr-x. 2 root root   6 Mar 10  2016 bin
drwxr-xr-x. 2 root root   6 Mar 10  2016 etc
drwxr-xr-x. 2 root root   6 Mar 10  2016 games
drwxr-xr-x. 2 root root   6 Mar 10  2016 include
drwxr-xr-x. 2 root root   6 Mar 10  2016 lib
drwxr-xr-x. 2 root root   6 Mar 10  2016 lib64
drwxr-xr-x. 2 root root   6 Mar 10  2016 libexec
lrwxrwxrwx  1 root root  36 Aug 14 16:00 mysql -> mysql-5.7.22-linux-glibc2.12-x86_64/
drwxr-xr-x  9 root root 129 Aug 14 00:16 mysql-5.7.22-linux-glibc2.12-x86_64
drwxr-xr-x. 2 root root   6 Mar 10  2016 sbin
drwxr-xr-x. 5 root root  49 Jun 13 19:03 share
drwxr-xr-x. 2 root root   6 Mar 10  2016 src


//修改目录/usr/local/mysql的属主属组
[root@localhost ~]# chown -R mysql.mysql /usr/local/mysql
[root@localhost ~]# ll /usr/local/mysql -d
lrwxrwxrwx 1 mysql mysql 36 Aug 14 16:00 /usr/local/mysql -> mysql-5.7.22-linux-glibc2.12-x86_64/

//配置环境变量
[root@localhost ~]# echo 'export PATH=/usr/local/mysql/bin:$PATH' > /etc/profile.d/mysql.sh
[root@localhost ~]# . /etc/profile.d/mysql.sh
[root@localhost ~]# echo $PATH
/usr/local/mysql/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

创建各个数据存放的目录

[root@localhost ~]# mkdir -p /opt/data/{3306,3307,3308}

[root@localhost ~]# chown -R mysql.mysql /opt/data/

[root@localhost ~]# ll /opt/data/
总用量 0
drwxr-xr-x 2 mysql mysql 6 5月   9 21:24 3306
drwxr-xr-x 2 mysql mysql 6 5月   9 21:24 3307
drwxr-xr-x 2 mysql mysql 6 5月   9 21:24 3308

[root@localhost ~]# tree /opt/data/
/opt/data/
├── 3306
├── 3307
└── 3308

3 directories, 0 files

初始化各实例

//初始化3306实例
[root@localhost ~]# mysqld --initialize --datadir=/opt/data/3306 --user=mysql
2019-05-10T01:43:33.987463Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2019-05-10T01:43:34.565759Z 0 [Warning] InnoDB: New log files created, LSN=45790
2019-05-10T01:43:34.733540Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2019-05-10T01:43:34.808595Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 061b480e-72c5-11e9-ae30-000c29c0ed3b.
2019-05-10T01:43:34.810131Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2019-05-10T01:43:34.837499Z 1 [Note] A temporary password is generated for root@localhost: Y=lJV79Rkx,d
[root@localhost ~]# echo 'Y=lJV79Rkx,d' > 3306_pass


//初始化3307实例
[root@localhost ~]# mysqld --initialize --datadir=/opt/data/3307 --user=mysql
2019-05-10T01:45:41.206120Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2019-05-10T01:45:42.082891Z 0 [Warning] InnoDB: New log files created, LSN=45790
2019-05-10T01:45:42.258639Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2019-05-10T01:45:42.352269Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 5220e72b-72c5-11e9-b195-000c29c0ed3b.
2019-05-10T01:45:42.353339Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2019-05-10T01:45:42.354494Z 1 [Note] A temporary password is generated for root@localhost: bpG+yqeGN8G:
[root@localhost ~]# echo 'bpG+yqeGN8G:' > 3307_pass

//3308
[root@localhost ~]# mysqld --initialize --datadir=/opt/data/3308 --user=mysql
2019-05-10T01:46:52.707755Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2019-05-10T01:46:53.546346Z 0 [Warning] InnoDB: New log files created, LSN=45790
2019-05-10T01:46:53.732779Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2019-05-10T01:46:53.810767Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 7cb89aad-72c5-11e9-b5a1-000c29c0ed3b.
2019-05-10T01:46:53.813509Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2019-05-10T01:46:53.815051Z 1 [Note] A temporary password is generated for root@localhost: wior7yf:1Awu
[root@localhost ~]# echo 'wior7yf:1Awu' > 3308_pass

安装perl

[root@localhost ~]# yum -y install perl

配置配置文件/etc/my.cnf

[root@localhost ~]# vim /etc/my.cnf
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin

[mysqld3306]
datadir = /opt/data/3306
port = 3306
socket = /tmp/mysql3306.sock
pid-file = /opt/data/3306/mysql_3306.pid
log-error=/var/log/3306.log

[mysqld3307]
datadir = /opt/data/3307
port = 3307
socket = /tmp/mysql3307.sock
pid-file = /opt/data/3307/mysql_3307.pid
log-error=/var/log/3307.log

[mysqld3308]
datadir = /opt/data/3308
port = 3308
socket = /tmp/mysql3308.sock
pid-file = /opt/data/3308/mysql_3308.pid
log-error=/var/log/3308.log

启动各实例

[root@localhost ~]# mysqld_multi start 3306
[root@localhost ~]# mysqld_multi start 3307
[root@localhost ~]# mysqld_multi start 3308
[root@localhost ~]# ss -antl
State      Recv-Q Send-Q     Local Address:Port                    Peer Address:Port
LISTEN     0      128                    *:22                                 *:*
LISTEN     0      100            127.0.0.1:25                                 *:*
LISTEN     0      80                    :::3307                              :::*
LISTEN     0      80                    :::3308                              :::*
LISTEN     0      128                   :::22                                :::*
LISTEN     0      100                  ::1:25                                :::*
LISTEN     0      80                    :::3306                              :::*

初始化密码

[root@localhost ~]# ls
3306_pass  3307_pass  3308_pass  anaconda-ks.cfg
[root@localhost ~]# cat 3306_pass
Y=lJV79Rkx,d
[root@localhost ~]# mysql -uroot -p'Y=lJV79Rkx,d' -S /tmp/mysql3306.sock
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.22

Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> set password = password('wangqing123!');
Query OK, 0 rows affected, 1 warning (0.01 sec)

mysql> quit
Bye



[root@localhost ~]# cat 3307_pass
bpG+yqeGN8G:
[root@localhost ~]# mysql -uroot -p'bpG+yqeGN8G:' -S /tmp/mysql3307.sock -e 'set password = password("wangqing123!");' --connect-expired-password
mysql: [Warning] Using a password on the command line interface can be insecure.


[root@localhost ~]# cat 3308_pass
wior7yf:1Awu
[root@localhost ~]# mysql -uroot -p'wior7yf:1Awu' -S /tmp/mysql3308.sock -e 'set password = password("wangqing123!");' --connect-expired-password
mysql: [Warning] Using a password on the command line interface can be insecure.