Mysql Centos 7 crashes. How to fix?

Question

MySQL

Moving from Freebsd8 to Centos7 and ran into a problem. I installed nginx + php-fpm and mysql on a clean VDS 500mb, but after a couple of hours of work, mysql fell off. This surprised me because freebsd didn't have this kind of problem.
How to configure mysql so that it continues to work if there is not enough RAM?
Well, it still doesn't work:

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

151218 07:15:13 mysqld_safe Number of processes running now: 0
151218 07:15:13 mysqld_safe mysqld restarted
151218  7:15:13 [Note] /usr/libexec/mysqld (mysqld 5.5.44-MariaDB) starting as process 16908 ...
151218  7:15:13 InnoDB: The InnoDB memory heap is disabled
151218  7:15:13 InnoDB: Mutexes and rw_locks use GCC atomic builtins
151218  7:15:13 InnoDB: Compressed tables use zlib 1.2.7
151218  7:15:13 InnoDB: Using Linux native AIO
151218  7:15:13 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137756672 bytes) failed; errno 12
151218  7:15:13 InnoDB: Completed initialization of buffer pool
151218  7:15:13 InnoDB: Fatal error: cannot allocate memory for the buffer pool
151218  7:15:13 [ERROR] Plugin 'InnoDB' init function returned error.
151218  7:15:13 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
151218  7:15:13 [ERROR] mysqld: Out of memory (Needed 128917504 bytes)
151218  7:15:13 [ERROR] mysqld: Out of memory (Needed 96681984 bytes)
151218  7:15:13 [ERROR] mysqld: Out of memory (Needed 72499200 bytes)
151218  7:15:13 [Note] Plugin 'FEEDBACK' is disabled.
151218  7:15:13 [ERROR] Unknown/unsupported storage engine: InnoDB
151218  7:15:13 [ERROR] Aborting

151218  7:15:13 [Note] /usr/libexec/mysqld: Shutdown complete

Answer 1

reduce the pool size innodb_buffer_pool_size to...

Answer 2

Same trouble. mariadb lies and does not start.
I tried as Max recommended above - I entered the
line
[mysqld]
innodb_buffer_pool_size=64000000 into /etc/my.cnf
and tried to reboot systemctl start mariadb
wrote: Job for mariadb.service failed because the control process exited with error code. See "systemctl status mariadb.service" and "journalctl -xe" for details.
and does not start. I can't figure out how to solve it :(
Did you succeed, Vincent1 ?