yum 安装好 mysql 后出现无法新建数据库，只要进入数据，按照下面的教程： https://linode.com/docs/databases/mysql/how-to-install-mysql-on-centos-7/ 新建数据库 会出现：Access denied for user 'xxx'@'%' to database 'xxxx'

于是 google 了几个教程： https://blog.csdn.net/chun8416/article/details/50177117

但是修改后：现在无法启动 mysql 了，请问如何解决？

systemctl status mysqld.service -l

● mysqld.service - MySQL Community Server

Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)

Active: failed (Result: start-limit) since Wed 2018-06-13 15:47:14 UTC; 23s ago

Process: 4784 ExecStartPost=/usr/bin/mysql-systemd-start post (code=exited, status=0/SUCCESS)

Process: 4783 ExecStart=/usr/bin/mysqld_safe --basedir=/usr (code=exited, status=1/FAILURE)

Process: 4771 ExecStartPre=/usr/bin/mysql-systemd-start pre (code=exited, status=0/SUCCESS)

Main PID: 4783 (code=exited, status=1/FAILURE)

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: Failed to start MySQL Community Server.

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: Unit mysqld.service entered failed state.

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: mysqld.service failed.

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: mysqld.service holdoff time over, scheduling restart.

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: start request repeated too quickly for mysqld.service

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: Failed to start MySQL Community Server.

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: Unit mysqld.service entered failed state.

Jun 13 15:47:14 li1382-238.members.linode.com systemd[1]: mysqld.service failed.

／ var/log/mysqld.log 里面的日志

2018-06-13 15:35:05 3884 [Note] InnoDB: Waiting for purge to start

2018-06-13 15:35:05 3884 [Note] InnoDB: 5.6.40 started; log sequence number 1625997

2018-06-13 15:35:05 3884 [Note] Server hostname (bind-address): '*'; port: 3306

2018-06-13 15:35:05 3884 [Note] IPv6 is available.

2018-06-13 15:35:05 3884 [Note] - '::' resolves to '::';

2018-06-13 15:35:05 3884 [Note] Server socket created on IP: '::'.

2018-06-13 15:35:05 3884 [Note] /usr/sbin/mysqld: ready for connections.

Version: '5.6.40' socket: '/var/lib/mysql/mysql.sock' port: 3306 MySQL Community Server (GPL) 180613 15:47:08 mysqld_safe Logging to '/var/log/mysqld.log'.

180613 15:47:08 mysqld_safe A mysqld process already exists

180613 15:47:09 mysqld_safe Logging to '/var/log/mysqld.log'.

180613 15:47:10 mysqld_safe A mysqld process already exists

180613 15:47:11 mysqld_safe Logging to '/var/log/mysqld.log'.

180613 15:47:11 mysqld_safe A mysqld process already exists

180613 15:47:12 mysqld_safe Logging to '/var/log/mysqld.log'.

180613 15:47:12 mysqld_safe A mysqld process already exists

180613 15:47:13 mysqld_safe Logging to '/var/log/mysqld.log'.

180613 15:47:13 mysqld_safe A mysqld process already exists