mysqld启动失败

[root@localhost /]# /usr/libexec/mysqld
/usr/libexec/mysqld: Table 'mysql.plugin' doesn't exist
160413 11:57:35 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
160413 11:57:35  InnoDB: Initializing buffer pool, size = 8.0M
160413 11:57:35  InnoDB: Completed initialization of buffer pool
InnoDB: The first specified data file ./ibdata1 did not exist:
InnoDB: a new database to be created!
160413 11:57:35  InnoDB: Setting file ./ibdata1 size to 10 MB
InnoDB: Database physically writes the file full: wait...
160413 11:57:35  InnoDB: Log file ./ib_logfile0 did not exist: new to be created
InnoDB: Setting log file ./ib_logfile0 size to 5 MB
InnoDB: Database physically writes the file full: wait...
160413 11:57:35  InnoDB: Log file ./ib_logfile1 did not exist: new to be created
InnoDB: Setting log file ./ib_logfile1 size to 5 MB
InnoDB: Database physically writes the file full: wait...
InnoDB: Doublewrite buffer not found: creating new
InnoDB: Doublewrite buffer created
InnoDB: Creating foreign key constraint system tables
InnoDB: Foreign key constraint system tables created
160413 11:57:36  InnoDB: Started; log sequence number 0 0
160413 11:57:36 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist
[root@localhost /]# /usr/libexec/mysqld start]
/usr/libexec/mysqld: Table 'mysql.plugin' doesn't exist
160413 11:58:15 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
160413 11:58:15  InnoDB: Initializing buffer pool, size = 8.0M
160413 11:58:15  InnoDB: Completed initialization of buffer pool
InnoDB: Log scan progressed past the checkpoint lsn 0 37356
160413 11:58:15  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
InnoDB: Doing recovery: scanned up to log sequence number 0 44233
160413 11:58:15  InnoDB: Starting an apply batch of log records to the database...
InnoDB: Progress in percents: 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 
InnoDB: Apply batch completed
160413 11:58:15  InnoDB: Started; log sequence number 0 44233
/usr/libexec/mysqld: Too many arguments (first extra is 'start]').
Use --verbose --help to get a list of available options
160413 11:58:15 [ERROR] Aborting


160413 11:58:15  InnoDB: Starting shutdown...
160413 11:58:21  InnoDB: Shutdown completed; log sequence number 0 44233
160413 11:58:21 [Note] /usr/libexec/mysqld: Shutdown complete


[root@localhost /]# /usr/libexec/mysqld start
/usr/libexec/mysqld: Table 'mysql.plugin' doesn't exist
160413 11:58:24 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
160413 11:58:24  InnoDB: Initializing buffer pool, size = 8.0M
160413 11:58:24  InnoDB: Completed initialization of buffer pool
160413 11:58:24  InnoDB: Started; log sequence number 0 44233
/usr/libexec/mysqld: Too many arguments (first extra is 'start').
Use --verbose --help to get a list of available options
160413 11:58:24 [ERROR] Aborting


160413 11:58:24  InnoDB: Starting shutdown...
160413 11:58:29  InnoDB: Shutdown completed; log sequence number 0 44233
160413 11:58:29 [Note] /usr/libexec/mysqld: Shutdown complete


[root@localhost /]# ps aux|grep mysqld
root      7149  1.0  0.1   4356   740 pts/0    S+   11:58   0:00 grep mysqld
[root@localhost /]# /usr/libexec/mysqld --help
/usr/libexec/mysqld: Table 'mysql.plugin' doesn't exist
160413 11:58:49 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
/usr/libexec/mysqld  Ver 5.1.73 for redhat-linux-gnu on i386 (Source distribution)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.


Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.


Starts the MySQL database server.


Usage: /usr/libexec/mysqld [OPTIONS]

For more help options (several pages), use mysqld --verbose --help.

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启动mysqld时，出现以上错误

原因是不存在当前mysql用户的表。执行    /usr/bin/mysql_install_db --user=mysql

在重新启动即可