我尝试重新启动 mysql 5.7 :\nservice mysql restart
但它失败了，我不明白为什么：
\n\nJob for mariadb.service failed because the control process exited with error code.\nSee "systemctl status mariadb.service" and "journalctl -xe" for details.\n我没有看到日志中有什么问题：
\n\nsystemctl status mariadb.service\n\xe2\x97\x8f mariadb.service - MariaDB 10.1.37 database server\n Loaded: loaded (/lib/systemd/system/mariadb.service; enabled; vendor preset: enabled)\n Active: failed (Result: exit-code) since Mon 2019-02-25 22:02:52 GMT; 1min 9s ago\n Docs: man:mysqld(8)\n https://mariadb.com/kb/en/library/systemd/\n Process: 15467 ExecStartPre=/usr/bin/install -m 755 -o mysql -g root -d /var/run/mysqld (code=exited, status=127)\n Main PID: 28679 …