MySQL数据库多种安装方法及企业级安装实践(下篇)(3)

2017-02-26 17:38:36 48065 [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: 4f94404a-fc74-11e6-8112-000c292ece3f.

2017-02-26 17:38:36 48065 [Note] Server hostname (bind-address): ‘*’; port: 3306

2017-02-26 17:38:36 48065 [Note] IPv6 is available.

2017-02-26 17:38:36 48065 [Note]?? – ‘::’ resolves to ‘::’;

2017-02-26 17:38:36 48065 [Note] Server socket created on IP: ‘::’.

2017-02-26 17:38:36 48065 [Note] Event Scheduler: Loaded 0 events

2017-02-26 17:38:36 48065 [Note] /application/mysql-5.6.34/bin/mysqld: ready for connections.

Version: ‘5.6.34’? socket: ‘/application/mysql-5.6.34/tmp/mysql.sock’? port: 3306? Source distribution

本例查看了错误日志的命令及错误日志中的内容,这里省略了大部分日志内容,只给了默认10行,如果有错误,一般会显示error字样.

5)设置MySQL开机自启动.

[root@oldboy ~]# chkconfig –add mysqld

[root@oldboy ~]# chkconfig –list mysqld

mysqld???????? ?0:off??? ?1:off??? 2:on 3:on 4:on 5:on 6:off此外,将启动命令/etc/init.d/mysqld start放到/etc/rc.local里面实现开机自启动也可.

若MySQL安装及使用出现故障,可根据下面的分析思路进行检查.

细看所有执行命令返回的屏幕输出,不要忽略关键的输出内容.

辅助查看系统日志/var/log/messages.

如果是MySQL关联了其他服务,要同时查看相关服务的日志.

仔细阅读,重新查看操作的步骤是否正确,书写的命令及字符是不是都对.

经常查看各种服务运行日志是个很好的习惯,也是成长为高手的必经之路,你要不要成为高手?

3.2.5?将MySQL相关命令加入全局路径

如果不为MySQL的命令配置全局路径,就无法直接在命令行输入mysql这样的命令,只能用全路径命令(/application/mysql/bin/mysql),这种带着路径输入命令的方式很麻烦.下面来看看配置的具体方法.

1)确认mysql命令所在的路径.

root@oldboy /]# ls /application/mysql/bin/mysql

/application/mysql/bin/mysql

2)在PATH变量前面增加/application/mysql/bin路径,并追加到/etc/profile文件中.

[root@oldboy /]# echo ‘export PATH=/application/mysql/bin:$PATH’ >>/etc/profile

#<==注意,echo后是单引号呦,双引号是不行滴.

[root@oldboy /]# tail -1 /etc/profile

export PATH=/application/mysql/bin:$PATH

[root@oldboy /]# source /etc/profile

#<==执行source使上一行添加到/etc/profile中,内容直接生效

#<==以上命令的用途为,定义mysql全局路径,实现在任意路径执行mysql命令.

[root@oldboy ~]# echo $PATH

/application/mysql/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

#<==执行echo $PATH有/application/mysql/bin输出表示配置成功.

提示：更简单的设置方法为用下面命令做软链接：ln -s /application/mysql/bin/* /usr/local/sbin/,把mysql命令所在路径链接到全局路径/usr/local/sbin/的下面.

要特别强调的是,务必把MySQL命令路径放在PATH路径中其他路径的前面,可能会导致使用的mysql等命令和编译安装的mysql命令不是同一个,进而产生错误.下面的网址中给出了因为MySQL路径配置问题导致的错误案例：http://oldboy.blog.51cto.com/2561410/1122867,该错误实际上就是因为使用yum安装的MySQL客户端命令访问了编译安装的服务端而导致的.

3.2.6登录MySQL测试

登录并测试的命令如下：

[root@oldboy ~]# mysql?#<==直接敲mysql就进入数据库了,而且身份还是root.

Welcome to the MySQL monitor.? Commands end with ; or \g.

Your MySQL connection id is 2

Server version: 5.6.34 Source distribution

Copyright (c) 2000,2016,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>

提示：你还可以使用如下三种命令写法登录mysql：

mysql -uroot -p,

mysql -uroot,

mysql -uroot -p ‘密码’

若出现登录故障,可通过以下方法排查.

如果这里提示无法登录,排除了数据库启动问题后,则很可能是数据库初始化文件有问题.例如：

[root@oldboy ~]#?mysql

ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: NO)

解决办法：重新初始化数据库即可,此问题一般都是数据库初始化问题,或者数据库文件损坏,以及目录权限问题.

mysql> show databases; ?#<==查看当前的数据库

+——————–+

| Database?????????? |

+——————–+

| information_schema |

| mysql????????????? |

| performance_schema |

| test?????????????? |

+——————–+

4 rows in set (0.00 sec)

mysql> select user(); ?#<==查看当前的登录用户

+—————-+

| user()???????? |

+—————-+

| root@localhost |

+—————-+

1 row in set (0.00 sec)

mysql>? ?#<==快捷键ctrl+d,也可以使用quit或exit等.

MySQL安装完成后,默认情况下,管理员账号root是无密码的,极不安全,必须要处理一下.

3.2.7基本的MySQL安全配置

1.?为root用户设置密码

MySQL管理员的账号root密码默认为空,可以通过mysqladmin命令为mysql不同实例的数据库设置独立的密码.

[root@oldboy ~]# mysqladmin -u root password ‘oldboy123’?#<==为root用户设置密码oldboy123.

Warning: Using a password on the command line interface can be insecure.?#<==这里是一个警告,提醒用户命令行放置密码是不安全的,读者尽量不要在命令行输入密码,而是采取交互式的输入密码.

[root@oldboy ~]# mysql?#<==无法直接输入命令登录了.

ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: NO)

[root@oldboy ~]# mysql -uroot -p?#<==新的登录方式,也可以直接带密码mysql -uroot -poldboy123.

Enter password: ???????#<==输入新密码oldboy123,交互式输入密码不会记录在命令记录里,因此更安全.

Welcome to the MySQL monitor.? Commands end with ; or \g.

Your MySQL connection id is 5

Server version: 5.6.34 Source distribution

Copyright (c) 2000,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>

读者也可以执行mysql_secure_installation命令交互式地设置系统的用户密码.

2.?清理mysql服务器内无用的用户

select user,host from mysql.user;

+——+———–+

| user | host????? |

+——+———–+

| root | 127.0.0.1 |

| root | ::1?????? |

|????? | localhost |

| root | localhost |

|????? | oldboy??? |

| root | oldboy??? |

+——+———–+

6 rows in set (0.00 sec)

mysql> drop user root@’::1′;

Query OK,0 rows affected (0.00 sec)

mysql> drop user root@’oldboy’;

Query OK,0 rows affected (0.00 sec)

mysql> drop user ”@’oldboy’;

Query OK,0 rows affected (0.00 sec)

mysql> drop user ”@’localhost’;

Query OK,0 rows affected (0.00 sec)

mysql> select user,host from mysql.user;

+——+———–+

| user | host????? |

+——+———–+

| root | 127.0.0.1 |

| root | localhost |

+——+———–+

2 rows in set (0.00 sec)

提示：对于drop命令及数据库安全,后文会有详细讲解,?此处不执行也可以.

有时用drop命令可能无法删除对应用户.比如,当数据库内的host等字段为大写及特殊Linux主机名时,删除用户就会遇到问题,例如:

mysql> drop user ‘ ‘@’MySQL’;??

ERROR 1396 (HY000): Operation DROP USER failed for ‘ ‘@’mysql’

可使用DML语句,并采用delete命令删除来解决此问题,具体命令如下：

mysql> delete from mysql.user where user=” and host=’MySQL’;

Query OK,1 row affected (0.00 sec)

mysql> flush privileges;

Query OK,0 rows affected (0.00 sec)

3.?删除mysql数据库内无用的test库

mysql> drop database test;

Query OK,0 rows affected (0.00 sec)

mysql> show databases;

+——————–+

| Database?????????? |

+——————–+

| information_schema |

| mysql????????????? |

| performance_schema |

+——————–+

3 rows in set (0.00 sec)

有关更多的MySQL的安全措施,在后文会有更详细的讲解.

3.3 ?MySQL安装FAQ

问题1：在配置mysql时遇到错误.

出现的错误如下：

checking?for?tgetent?in?-ltinfo…?no
checking?for?termcap?functions?library…?configure:?error:?No?curses/termcap?library?found

原因：缺少ncurses安装包.

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