CentOS 7.7下Yum安装MySQL5.7

部署环境

• CentOS 7.7 64-bit Minimal
• MySQL 5.7

配置 yum 源

# 下载
$ wget https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm

# 安装 mysql 源
$ yum localinstall mysql57-community-release-el7-11.noarch.rpm

用下面的命令检查 mysql 源是否安装成功

$ yum repolist enabled | grep "mysql.*-community.*"
mysql-connectors-community/x86_64    MySQL Connectors Community              153
mysql-tools-community/x86_64         MySQL Tools Community                   110
mysql57-community/x86_64             MySQL 5.7 Community Server              424

安装 MySQL

使用 yum install 命令安装

$ yum install -y mysql-community-server

启动 MySQL 服务

启动/关闭服务的命令是 systemctl start|stop

$ systemctl start mysqld

用 systemctl status 查看 MySQL 状态

$ systemctl status mysqld
?.mysqld.service - MySQL Server
   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
   Active: active (running) since Thu 2020-06-18 10:38:20 CST; 38s ago
     Docs: man:mysqld(8)
           http://dev.mysql.com/doc/refman/en/using-systemd.html
  Process: 13691 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
  Process: 13629 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
 Main PID: 13694 (mysqld)
   CGroup: /system.slice/mysqld.service
           ?..13694 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid

Jun 18 10:38:13 VM_0_10_centos systemd[1]: Starting MySQL Server...
Jun 18 10:38:20 VM_0_10_centos systemd[1]: Started MySQL Server.

设置开机启动

$ systemctl enable mysqld
# 重载所有修改过的配置文件
$ systemctl daemon-reload

修改 root 本地账户密码

mysql 安装完成之后，生成的默认密码在 /var/log/mysqld.log 文件中。使用 grep 命令找到日志中的密码。

$ grep 'temporary password' /var/log/mysqld.log
2020-06-18T02:38:15.404832Z 1 [Note] A temporary password is generated for root@localhost: kn;RYrESq9xz

首次通过初始密码登录后，使用以下命令修改密码：

mysql -uroot -p
ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!'; 
flush privileges;

以后通过 update set 语句修改密码：

mysql> use mysql;
mysql> update user set password=PASSWORD('MyNewPass5!') where user='root';
mysql> flush privileges;

注意：mysql 5.7 默认安装了密码安全检查插件（validate_password），默认密码检查策略要求密码必须包含：大小写字母、数字和特殊符号，并且长度不能少于8位。否则会提示 ERROR 1819 (HY000): Your password does not satisfy the current policy requirements 错误。

添加远程登录用户

默认只允许root帐户在本地登录，如果要在其它机器上连接 mysql，必须添加一个允许远程连接的帐户。或者修改 root 为允许远程连接（不推荐） 。

添加一个允许远程连接的帐户：

mysql> GRANT ALL PRIVILEGES ON *.* TO 'zuozewei'@'%' IDENTIFIED BY 'Zuozewei2020!' WITH GRANT OPTION;

修改 root 为允许远程连接（不推荐）:

mysql> use mysql;
mysql> UPDATE user SET Host='%' WHERE User='root';
mysql> flush privileges;
mysql> quit

设置默认编码为 utf8

mysql 安装后默认不支持中文，需要修改编码。
修改 /etc/my.cnf 配置文件，在相关节点（没有则自行添加）下添加编码配置，如下：

$ vim /etc/my.cnf

[mysqld]
character-set-server=utf8
[client]
default-character-set=utf8
[mysql]
default-character-set=utf8

重启 mysql 服务，查询编码：

$ systemctl restart mysqld
$ mysql -uroot -p
$ show variables like 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

默认配置文件路径

• 配置文件：/etc/my.cnf
• 日志文件：/var/log/mysqld.log
• 服务启动脚本：/usr/lib/systemd/system/mysqld.service
• socket 文件：/var/run/mysqld/mysqld.pid