msyql 启动报错 找不到pid 文件

安装完mysql 启动mysql 数据库 

报错 

Starting MySQL.The server quit without updating PID file (/app/mysql/mysql/data/mysqld.pid).[FAILED]Starting MySQL.The server quit without updating PID file (/app/mysql/mysql/data/mysqld.pid).[FAILED]

查看报错日志 

2017-07-11T02:23:04.368749Z 0 [ERROR] InnoDB: mmap(137428992 bytes) failed; errno 12

2017-07-11T02:23:04.368761Z 0 [ERROR] InnoDB: Cannot allocate memory for the buffer pool

2017-07-11T02:23:04.368767Z 0 [ERROR] InnoDB: Plugin initialization aborted with error Generic error

2017-07-11T02:23:04.368775Z 0 [ERROR] Plugin 'InnoDB' init function returned error.

2017-07-11T02:23:04.368779Z 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.

2017-07-11T02:23:04.368784Z 0 [ERROR] Failed to initialize plugins.

2017-07-11T02:23:04.368788Z 0 [ERROR] Aborting

判断是 内存问题 

修改 buffer pool 的内存大小

innodb_buffer_pool_size=8M

重启数据库，可以正常启动了