本文涉及的相关环境和版本为：CentOS-7.9-x64、MySQL-8.0.36
卸载MariaDB
要先卸载掉 centos 自带的 mariadb 数据库，不然可能会影响 mysql 的安装，同时确保目前没有安装 mysql
[root@CentOS79 ~]# rpm -qa | grep mariadb
mariadb-libs-5.5.68-1.el7.x86_64
[root@CentOS79 ~]# rpm -e mariadb-libs --nodeps
[root@CentOS79 ~]# rpm -qa | grep mariadb
[root@CentOS79 ~]#
[root@CentOS79 ~]# rpm -qa | grep mysql
[root@CentOS79 ~]#
安装MySQL
下载地址：https://cdn.mysql.com//Downloads/MySQL-8.0/mysql-8.0.36-linux-glibc2.17-x86_64.tar.xz
注意下载时选择的 glibc 版本，可以通过命令 ldd --version 查看（查看 gcc 版本使用 gcc -v）
[Jadyer@CentOS79 ~]$ cd /app/software/
[Jadyer@CentOS79 software]$ tar xvf mysql-8.0.36-linux-glibc2.17-x86_64.tar.xz
[Jadyer@CentOS79 software]$ mkdir -pv /app/mysql-8.0.36/mysql_data
[Jadyer@CentOS79 software]$ mv mysql-8.0.36-linux-glibc2.17-x86_64 /app/mysql-8.0.36/mysql
[root@CentOS79 ~]# groupadd MySQL # 添加MySQL组
[root@CentOS79 ~]# useradd -s /sbin/nologin -M -g MySQL mysql # 创建mysql用户并分配组，且不能shell登录
[root@CentOS79 ~]# chown -R mysql:MySQL /app/mysql-8.0.36/
配置MySQL
[root@CentOS79 ~]# cd /app/mysql-8.0.36/mysql/bin/
[root@CentOS79 bin]# ./mysqld --initialize-insecure --user=mysql --basedir=/app/mysql-8.0.36/mysql --datadir=/app/mysql-8.0.36/mysql_data
[Server] /app/mysql-8.0.36/mysql/bin/mysqld (mysqld 8.0.36) initializing of server in progress as process 17071
[InnoDB] InnoDB initialization has started.
[InnoDB] InnoDB initialization has ended.
[Server] root@localhost is created with an empty password ! Please consider switching off the --initialize-insecure option.
这时就会初始化 mysql_data 目录，同时创建了 root 用户，且密码为空
--initialize参数才会生成随机密码，--initialize-insecure生成的是空密码
接下来继续配置，并加入自启动
[root@CentOS79 ~]# vim /etc/profile
# Set MySQL Environment Variable
MySQL_HOME=/app/mysql-8.0.36/mysql
PATH=$MySQL_HOME/bin:$PATH
export MySQL_HOME PATH
[root@CentOS79 ~]# echo $PATH
[root@CentOS79 ~]# source /etc/profile
[root@CentOS79 ~]# echo $PATH
[root@CentOS79 ~]# cd /app/mysql-8.0.36/mysql/support-files/
[root@CentOS79 support-files]# cp mysql.server /etc/init.d/mysqld # 拷贝启动脚本
[root@CentOS79 support-files]# chmod +x /etc/init.d/mysqld # 赋予可执行权限
[root@CentOS79 support-files]# chkconfig --add mysqld # 加入系统服务
[root@CentOS79 support-files]# chkconfig mysqld on # 开机启动
[root@CentOS79 support-files]# vim /etc/my.cnf # 编写MySQL启动配置
[root@CentOS79 support-files]# cd /app/mysql-8.0.36/mysql_data/
[root@CentOS79 mysql_data]# mkdir binlog
[root@CentOS79 mysql_data]# chown -R mysql:MySQL binlog/
my.cnf 配置的内容如下
[mysql]
default-character-set = utf8mb4
socket = /app/mysql-8.0.36/mysql_data/mysql.sock
[client]
default-character-set = utf8mb4
socket = /app/mysql-8.0.36/mysql_data/mysql.sock
[mysqld]
#lower_case_table_names = 1（实测发现：只要配置了该参数，就会导致无法启动mysql）
#skip-grant-tables
server-id = 53306 # Mysql唯一标识（一个集群中唯一）
port = 3306 # 服务端口（默认3306）
user = mysql # 启动用户（官方不建议root启动数据库）
basedir = /app/mysql-8.0.36/mysql # mysql的安装目录
datadir = /app/mysql-8.0.36/mysql_data # mysql的数据存放目录
socket = /app/mysql-8.0.36/mysql_data/mysql.sock # 指定套接字文件
pid-file = /app/mysql-8.0.36/mysql_data/mysqld.pid # 指定pid文件
max_connections = 200 # 允许最大连接数
max_connect_errors = 10 # 允许连接失败的次数
slow_query_log = 1 # 开启慢查询日志
slow_query_log_file = /app/mysql-8.0.36/mysql_data/slow_query.log # 指定慢查询日志文件
long_query_time = 3 # 指定3秒返回查询的结果为慢查询
log-error = /app/mysql-8.0.36/mysql_data/mysql-error.log
log-bin = /app/mysql-8.0.36/mysql_data/binlog/mysql-bin
skip-name-resolve = 1
default-storage-engine = INNODB
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
init_connect = 'SET NAMES utf8mb4'
init_connect = 'SET collation_connection = utf8mb4_unicode_ci'
[mysqldump]
quick
max_allowed_packet = 16M
[mysqlhotcopy]
interactive-timeout
启动MySQL
通过命令 service mysqld start 手动启动数据库
初次登录：mysql -uroot，然后设置 root 用户的密码和权限
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'xuanyu123456';
mysql> UPDATE user SET Host='%' WHERE User='root';
mysql> FLUSH PRIVILEGES;
再创建一个新用户dev，以后用新用户访问数据库open
mysql> CREATE DATABASE IF NOT EXISTS open DEFAULT CHARSET UTF8MB4 COLLATE UTF8MB4_UNICODE_CI;
mysql> CREATE USER 'dev'@'%' IDENTIFIED BY 'dev';
mysql> GRANT CREATE ON open.* TO 'dev'@'%';
mysql> GRANT CREATE, SELECT, INSERT, UPDATE, DELETE, DROP ON open.* TO 'dev'@'%';
若报错：[1044] Access denied for user 'root'@'%' to database，执行以下命令即可
mysql> mysql -uroot -pxxxxx
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;