一、清理环境

1、检查是否已经安装过mysql，执行命令
rpm -qa | grep mysql

如果查出来有安装包，使用如下命令清理
rpm -e --nodeps `rpm -qa | grep mysql`

再次执行查询命令，查看是否删除

2、查询所有Mysql对应的文件夹
whereis mysql
mysql: /usr/bin/mysql /usr/include/mysql

find / -name mysql
/data/mysql
/data/mysql/mysql

删除相关目录或文件
rm -rf /usr/bin/mysql /usr/include/mysql /data/mysql /data/mysql/mysql

验证是否删除完毕
whereis mysql
find / -name mysql

3、检查mysql用户组和用户是否存在，如果没有，则创建
cat /etc/group | grep mysql
cat /etc/passwd |grep mysql
groupadd mysql
useradd -s /sbin/nologin -M mysql

二、安装部署mysql-5.7

1.创建mysql目录
mkdir /root/soft

cd /root/soft

2.下载安装包并解压
wget https://cdn.mysql.com/archives/mysql-5.7/mysql-5.7.28-linux-glibc2.12-x86_64.tar.gz
tar -xf mysql-5.7.28-linux-glibc2.12-x86_64.tar.gz

3.移动到指定目录下并更名
mv mysql-5.7.28-linux-glibc2.12-x86_64 /usr/local/mysql

4.安装mysql5.7的依赖包
yum install -y libaio-devel numactl

5.设置环境变量
echo 'export PATH=$PATH:/usr/local/mysql/bin' >> /etc/profile
source /etc/profile

mysql -V
mysql  Ver 14.14 Distrib 5.7.43, for Linux (x86_64) using  EditLine wrapper


6.创建数据目录，并授权
mkdir /usr/local/mysql/data
mkdir /usr/local/mysql/logs
chown -R mysql:mysql /usr/local/mysql
chmod -R 755 /usr/local/mysql

7.编译安装并初始化mysql
cd /usr/local/mysql/bin
./mysqld --initialize-insecure --user=mysql --datadir=/usr/local/mysql/data --basedir=/usr/local/mysql

8.编辑配置文件my.cnf，添加配置如下
cat >/etc/my.cnf <<'EOF'

[mysqld]
port=3306
user=mysql
basedir=/usr/local/mysql  # 应用目录
datadir=/usr/local/mysql/data  # 数据目录
socket=/usr/local/mysql/mysql.sock  # socket文件目录
server-id=100  # 主机id，必须要区别于其他机器
log_bin=/usr/local/mysql/logs/mysql-bin  # binlog日志目录
character_set_server=utf8mb4  # 设置全局字符为utf8mb4

[mysql]
socket=/usr/local/mysql/mysql.sock
EOF

三、启动脚本

cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld

启动服务
systemctl enable mysqld
systemctl restart mysqld
systemctl status mysqld

如果想前台启动
mysqld_safe --defaults-file=/etc/my.cnf

四、登录mysql，修改密码

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

五、开放远程连接

mysql>use mysql;
msyql>update user set user.Host='%' where user.User='root';
mysql>flush privileges;