CentOS7 安装Mysql

1. 下载上传解压

1.1 下载

1.2 上传

$ rz

1.3 解压

$ tar -zxvf mysql-5.7.36-linux-glibc2.12-x86_64.tar.gz 
$ mv  mysql-5.7.36-linux-glibc2.12-x86_64  /home/flying/program/mysql-5.7.36

2. 配置

2.1 使用root用户创建mysql组及mysql用户，并授权

$ groupadd mysql
$ useradd -g mysql mysql

更改mysql-5.7.36 文件夹所有者属性和对应权限

$ chown -R mysql:mysql  /home/flying/program/mysql-5.7.36
$ chown -R mysql  /home/flying/program/mysql-5.7.36
$ chmod -R 755 /home/flying/program/mysql-5.7.36

2.2 创建数据存放目录并授权

$ mkdir data
$ cd data

$ chown -R mysql:mysql /home/mysql/data
$ chown -R mysql  /home/mysql/data
$ chmod -R 755 /home/mysql/data

2.3 配置my.cnf文件

$ vim /etc/my.cnf

[mysqld]
basedir=/home/flying/program/mysql-5.7.36
datadir=/home/mysql/data
socket=/var/lib/mysql/mysql.sock
character_set_server=utf8mb4
explicit_defaults_for_timestamp=true

3. 初始化mysql命令

$ ./mysqld --user=mysql --basedir=/home/flying/program/mysql-5.7.36 --datadir=/home/mysql/data --initialize

4. 将mysql加入服务并设置开机自启动

$ cp /home/flying/program/mysql-5.7.36/support-files/mysql.server  /etc/init.d/mysql
$ chkconfig mysql on

5. 启动mysql

service mysql start

启动报错

Starting MySQL.2022-05-22T12:46:45.126162Z mysqld_safe error: log-error set to '/var/log/mariadb/mariadb.log', however file don't exists. Create writable for user 'mysql'.
 ERROR! The server quit without updating PID file (/home/mysql/data/host2100.pid).

错误修复

$ mkdir /var/log/mariadb
$ touch /var/log/mariadb/mariadb.log
$ chown -R mysql:mysql /var/log/mariadb/

重新启动出现socket异常

Starting MySQL.2022-05-22T12:50:59.338574Z mysqld_safe Directory '/var/lib/mysql' for UNIX socket file don't exists

修复socket

 socket=/home/mysql/data/mysql.sock

再次重启，mysql成功启动

Starting MySQL. SUCCESS!

6. linux系统内mysql命令登录测试

6.1 登录异常，bash: mysql: 未找到命令

因为/usr/local/bin目录下缺失mysql导致，只需要一下方法建立软链接，即可以解决：
把mysql安装目录，比如MYSQLPATH/bin/mysql，映射到/usr/local/bin目录下：

$ cd /usr/local/bin
$ ln -fs /MYSQLPATH/bin/mysql mysql

6.2 重新登录出现以下问题

 Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

修复问题
原因找不到mysql.sock，解决：只需在tmp文件夹下创建一个软连接即可解决

$ find / -name mysql.sock
/home/mysql/data/mysql.sock #找到路径
$ ln -s /home/mysql/data/mysql.sock /tmp/mysql.sock

6.3 重新登录，忘记初始密码，解决方案

$ mysql -u root -p
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

在/etc/my.cnf中加入如下内容：在[mysqld]下添加skip-grant-tables，然后保存并退出

[mysqld]
 skip-grant-tables  #新增这一行
 basedir=/home/flying/program/mysql-5.7.36

重启mysql服务，重新登录无密码登录

$ mysql -uroot -p

修改密码

mysql> use mysql
mysql> update user set authentication_string=password('123456') where user='root';
mysql> flush privileges;
mysql> exit;

密码修改后，最后把/etc/my.cnf中的skip-grant-tables注释掉，然后重启mysql

[mysqld]
 #skip-grant-tables  #新增这一行
 basedir=/home/flying/program/mysql-5.7.36

$ service mysql restart
$ mysql -uroot -p 
输入新设置的密码登录成功

7. linux系统外通过客户端工具登录测试

7.1. 对外开放3306端口

$ firewall-cmd --permanent --add-port=3306/tcp
$ firewall-cmd --reload

7.2 通过客户端连接mysql

修改mysql root用户只允许本地连接为允许远程连接

mysql> use mysql;
mysql> update user set host='%' where user='root';
mysql> flush privileges;
mysql> select user,host from user;
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY '123456' WITH GRANT OPTION;
mysql> flush privileges;

再次重新连接

至此，mysql数据库安装成功