mysql无法启动

[root@zdcs01 mysql]# /etc/init.d/mysqld start
MySQL Daemon failed to start.
Starting mysqld:  [FAILED]

查报错日志，发现没有错误日志：

[root@zdcs01 mysql]# cat /etc/my.cnf | grep log_error
log_error          = /var/log/mysqld.log
[root@zdcs01 mysql]# ll /var/log/mysqld.log 
-rw-r----- 1 mysql mysql 0 Jun 24 00:40 /var/log/mysqld.log

查启动报错日志：

[root@zdcs01 mysql]# cat /etc/my.cnf | grep datadir 
datadir   = /hadoop/mysql
[root@zdcs01 mysql]# cd /hadoop/mysql
[root@zdcs01 mysql]# ls -ltr | grep *.err
-rw-r----- 1 mysql root     34284 Jun 24 00:40 zdcs01.err

[root@zdcs01 mysql]# cat zdcs01.err 

...............................

160624  0:30:02 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist

...............................

解决方法：

mysql_install_db

执行上述命令后，重启mysql，问题解决。