the reason

It appears in the mysql error log: The innodb_system data file’ibdata1′ must be writable, literally: ibdata1 must be writable

Check the log and report an error, the folder has no write permission

cat /var/log/mysqld.log

solve

Find file path

find / -name ibdata1

Grant folder permissions

chmod -R 777 /var/lib/mysql
chown mysql:mysql -R /var/lib/mysql

Start MySQL

systemctl start mysqld.service
// CHECK MySQL STATUS
systemctl status mysqld.service