1.卸载原来的数据库
1.1 查询所安装的MariaDB组件：
[root@localhost logs]# rpm -qa | grep Maria*
MariaDB-server-5.5.49-1.el7.centos.x86_64
MariaDB-common-5.5.49-1.el7.centos.x86_64
MariaDB-client-5.5.49-1.el7.centos.x86_64
1.2 卸载数据库：
[root@localhost logs]# yum -y remove mari*
1.3 删除数据库文件：
[root@localhost logs]# rm -rf /var/lib/mysql/*
2. 安装mysql5.7
2.1 下载解压Mysql
```
wget https://obs.cn-north-4.myhuaweicloud.com/obs-mirror-ftp4/database/mysql-5.7.27-aarch64.tar.gz
tar xvf mysql-5.7.27-aarch64.tar.gz
mv /usr/local/mysql-5.7.27-aarch64 /usr/local/mysql
```
2.2 创建相关依赖
```
mkdir -p /usr/local/mysql/logs //创建logs目录
ln -sf /usr/local/mysql/my.cnf /etc/my.cnf
cp -rf /usr/local/mysql/extra/lib* /usr/lib64/
mv /usr/lib64/libstdc++.so.6 /usr/lib64/libstdc++.so.6.old
ln -s /usr/lib64/libstdc++.so.6.0.24 /usr/lib64/libstdc++.so.6
```
2.3 创建mysql组
```
groupadd mysql
useradd -g mysql mysql
chown -R mysql:mysql /usr/local/mysql
```
2.4 设置开机启动
```
cp -rf /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld
chmod +x /etc/init.d/mysqld
systemctl enable mysqld
```
2.5 添加环境变量
/etc/profile添加下面两行代码：
```
export MYSQL_HOME=/usr/local/mysql
export PATH=$PATH:$MYSQL_HOME/bin
```
source /etc/profile
2.6 启动mysql
初始化mysql
mysqld --initialize-insecure --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data
开启mysql
systemctl start mysqld
查看状态
systemctl status mysqld
2.7 修改密码
mysql -u $mysql_user -e "GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY '$mysql_password';flush privileges;"
mysql -u $mysql_user -e "update mysql.user set authentication_string=password('$mysql_password') where user='root' and host='localhost';flush privileges;"
3. 重新初始化数据库
需要预创建的数据库重新创建，比如初始化scm库
scm_prepare_database.sh mysql scm scm xxx