03_mysql运维核心基础

03_mysql运维核心基础

1.启动，关闭mysql

脚本启动，是后台启动
systemctl start/stop/restart mysqld

service mysqld start 

/etc/init.d/mysqld start 

其实脚本也依然是mysql提供的二进制命令启动的

[root@db-51 /www.yuchaoit.cn]#ls /opt/mysql/bin/mysqld* -l
-rwxr-xr-x 1 mysql mysql 260613605 Sep 27  2019 /opt/mysql/bin/mysqld
-rwxr-xr-x 1 mysql mysql 213374233 Sep 27  2019 /opt/mysql/bin/mysqld-debug
-rwxr-xr-x 1 mysql mysql     27139 Sep 27  2019 /opt/mysql/bin/mysqld_multi
-rwxr-xr-x 1 mysql mysql     28494 Sep 27  2019 /opt/mysql/bin/mysqld_safe
-rwxr-xr-x 1 mysql mysql  15712383 Sep 27  2019 /opt/mysql/bin/mysqldump
-rwxr-xr-x 1 mysql mysql      7865 Sep 27  2019 /opt/mysql/bin/mysqldumpslow

mysqld_safe 和mysqld的区别

mysql_safe作用

1. mysql官方启动脚本，是以执行mysqld_safe为入口，其实mysqld_safe也是个shell脚本，调用了myqsld命令启动服务

2.mysqld_safe脚本设置运行环境，如以守护进程运行
3.mysqld_safe检测mysqld运行状态
4.mysqld_safe检测mysqld进程运行信息，写入 mysql实例目录下的hostname.err文件
5.以及mysqld_safe会读取my.cnf配置文件的[mysqld],[mysqld_safe]等配置

2.关闭mysql

脚本关闭

systemctl stop mysqld
service mysqld stop
/etc/init.d/mysqld stop

命令关闭

mysql -uroot -pwww.yuchaoit.cn -e 'shutdown;'


[root@db-51 /www.yuchaoit.cn]#netstat -tunlp|grep mysql
tcp6       0      0 :::3307                 :::*                    LISTEN      5004/mysqld         
tcp6       0      0 :::3308                 :::*                    LISTEN      5189/mysqld      


[root@db-51 /www.yuchaoit.cn]#systemctl start mysqld
[root@db-51 /www.yuchaoit.cn]#!net
netstat -tunlp|grep mysql
tcp6       0      0 :::3306                 :::*                    LISTEN      6598/mysqld         
tcp6       0      0 :::3307                 :::*                    LISTEN      5004/mysqld         
tcp6       0      0 :::3308                 :::*                    LISTEN      5189/mysqld

特殊情况下，不建议用这个操作

kill pid
pkill mysqld
killall mysqld

kill -9 pid # 极端情况下，才能用这个

4.配置文件模版

[root@db-51 ~]#cat /etc/my.cnf 
[mysqld] # 服务端标签
port=3306    # 端口
server_id # 主机编号，用于主从复制
user=mysql    # 内置运行用户
basedir=/opt/mysql    # 软件目录
datadir=/www.yuchaoit.cn/mysql_3306    # 数据目录
socket=/tmp/mysql.sock    # 套接字文件路径

[mysql]
socket=/tmp/mysql.sock    # mysql客户端连接数据库，默认读取的socket文件路径


配置语法
[server]                服务端读取的配置
[mysqld]                mysqld进程读取的配置
[mysqld_safe]        mysqld_safe脚本会加载的配置


客户端配置参数
[mysql]        客户端命令读取的设置
[client]    所有本地客户端读取的设置
[mysqldump]    备份命令读取的设置

5.远程连接管理

创建一个用户
mysql -uroot -pwww.yuchaoit.cn -e "grant all privileges on *.* to yuchao01@'localhost' identified by 'yuchao666';"

查看mysql的用户表

mysql> select User,Host,authentication_string from mysql.user;
+---------------+-----------+-------------------------------------------+
| User          | Host      | authentication_string                     |
+---------------+-----------+-------------------------------------------+
| root          | localhost | *E4270FA99E3E2D95856323D2C35CB2E4728028A1 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys     | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| yuchao01      | localhost | *518455521988924B96DD6FFF6F10BC59693382B0 |
+---------------+-----------+-------------------------------------------+
4 rows in set (0.00 sec)

本地账号登录

[root@db-51 ~]#mysql -uyuchao01 -pyuchao666

[root@db-51 ~]#mysql -uyuchao01 -pyuchao666 -h127.0.0.1

[root@db-51 ~]#mysql -uyuchao01 -pyuchao666 -hlocalhost

[root@db-51 ~]#mysql -uyuchao01 -pyuchao666 -h127.0.0.1 -P3306

使用mysql套接字登录

[root@db-51 ~]#mysql -uyuchao01 -pyuchao666 -S /tmp/mysql.sock -e "show databases;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+

远程连接

授权，允许访问的网段

1. 之允许yuchao02用户在10.0.0.x网段登录，有最大的权限
2. 授权语句只有root用户才能操作

mysql -uroot -pwww.yuchaoit.cn -S /tmp/mysql.sock -e "grant all on *.* to yuchao02@'10.0.0.%' identified by 'yuchao666';"

远程登录看看

[root@web-7 ~]#mysql -uyuchao02 -pyuchao666 -h10.0.0.51 -P3306
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 5.7.28 MySQL Community Server (GPL)

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

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

MySQL [(none)]> select user();
+-------------------+
| user()            |
+-------------------+
| yuchao02@10.0.0.7 |
+-------------------+
1 row in set (0.00 sec)

MySQL [(none)]>

navicat图形化访问

6.用户说明

Linux用户
- 管理文件
- 登录文件

mysql用户
- 登录mysql
- 管理mysql的库，表

6.3 用户管理

查看mysql用户列表

[root@db-51 ~]#mysql -uroot -pwww.yuchaoit.cn -e 'select User,Host,authentication_string from mysql.user;'
mysql: [Warning] Using a password on the command line interface can be insecure.
+---------------+-----------+-------------------------------------------+
| User          | Host      | authentication_string                     |
+---------------+-----------+-------------------------------------------+
| root          | localhost | *E4270FA99E3E2D95856323D2C35CB2E4728028A1 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys     | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| yuchao01      | localhost | *518455521988924B96DD6FFF6F10BC59693382B0 |
| yuchao02      | 10.0.0.%  | *518455521988924B96DD6FFF6F10BC59693382B0 |
| bob01         | 10.0.0.7  | *518455521988924B96DD6FFF6F10BC59693382B0 |
+---------------+-----------+-------------------------------------------+
[root@db-51 ~]#

创建用户

create user chaoge01@'localhost'; # 创建用户无密码

select user,host,authentication_string from mysql.user; # 查询

创建且设置密码

create user chaoge02@'localhost' identified by '123';

修改用户密码，root去修改

alter user chaoge01@'localhost' identified by '123';
alter user chaoge01@'localhost' identified by 'yuchaoge666';

改自己密码

[root@db-51 ~]#
[root@db-51 ~]#mysql -uchaoge02 -p123
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 27
Server version: 5.7.28 MySQL Community Server (GPL)

Copyright (c) 2000, 2019, 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('chaoge666');
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql>

删除用户

mysql> drop user chaoge02@'localhost';
Query OK, 0 rows affected (0.00 sec)

7.授权管理

权限的作用

限制mysql的用户，可以执行哪些SQL语句。

8.修改root密码

Mysqladmin改密码

[root@db-51 ~]#mysqladmin -uroot -pwww.yuchaoit.cn password yuchao666

set语句修改

mysql> set password for root@localhost=password('chaoge666');
Query OK, 0 rows affected, 1 warning (0.00 sec)


mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

update语句修改

mysql> update mysql.user set authentication_string=password("www.yuchaoit.cn") where user='root' and host='localhost';
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 1

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

刷新后，权限表会更新

用户修改自己密码

mysql> set password=password('yuchao666');
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql>

9.忘记root密码咋办

1.停止服务
[root@db-51 ~]#systemctl stop mysql

2.跳过授权表，免密运行mysqld服务端
[root@db-51 ~]#mysqld_safe --skip-grant-tables --user=mysql
2022-07-20T09:45:54.661054Z mysqld_safe Logging to '/www.yuchaoit.cn/mysql_3306/db-51.err'.
2022-07-20T09:45:54.684950Z mysqld_safe Starting mysqld daemon with databases from /www.yuchaoit.cn/mysql_3306


3.改密码
只能用update语句
mysql> update mysql.user set authentication_string=password('www.yuchaoit.cn') where user='root' and host='localhost';
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 1


4.停止mysql
mysql> shutdown;
Query OK, 0 rows affected (0.00 sec)


5.重启mysql
systemctl start mysql

再次登录
[root@db-51 ~]#mysql -uroot -pwww.yuchaoit.cn

6.提醒
授权表参数，会导致任意客户端，都可以免密直接登录，务必要记住要删掉