Mysql sock can't find it. - Codes Helper - Programming Question Answer

Mysql sock can't find it.

problem description

start Times error

mysql
ERROR 2002 (HY000): Can"t connect to local MySQL server through socket"/ var/lib/mysql/mysql.sock" (2)

there are no sock files in other directories

find /-name "* .sock"
/ run/chrony/chronyd.sock

failed to start

systemctl start mysqld.service
Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl-xe" for details.

status

systemctl status mysqld.service

2018-09-04T05:05:02.255889Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.12) starting as process 8174
2018-09-04T05:05:02.306416Z 0 [ERROR] [MY-012681] [InnoDB] InnoDB: mmap(137428992 bytes) failed; errno 12
2018-09-04T05:05:02.306595Z 1 [ERROR] [MY-012956] [InnoDB] InnoDB: Cannot allocate memory for the buffer pool
2018-09-04T05:05:02.306645Z 1 [ERROR] [MY-012930] [InnoDB] InnoDB: Plugin initialization aborted with error Generic error.
2018-09-04T05:05:02.306770Z 1 [ERROR] [MY-010334] [Server] Failed to initialize DD Storage Engine
2018-09-04T05:05:02.307077Z 0 [ERROR] [MY-010020] [Server] Data Dictionary initialization failed.
2018-09-04T05:05:02.307169Z 0 [ERROR] [MY-010119] [Server] Aborting
2018-09-04T05:05:02.310529Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.12)  MySQL Community Server - GPL.

system Centos7
mysql 8.0.12