Kill error

Hi dear
our server after works 6 or 7 hours we have kill in process

    ● elasticsearch.service - Elasticsearch
   Loaded: loaded (/usr/lib/systemd/system/elasticsearch.service; enabled; vendo                                  r preset: disabled)
   Active: failed (Result: signal) since Mon 2021-02-01 03:13:50 CET; 3h 39min a                                  go
     Docs: https://www.elastic.co
  Process: 23879 ExecStart=/usr/share/elasticsearch/bin/systemd-entrypoint -p ${                                  PID_DIR}/elasticsearch.pid --quiet (code=killed, signal=KILL)
 Main PID: 23879 (code=killed, signal=KILL)
Jan 31 16:29:30 vm7502678699.bitcommand.com systemd[1]: Starting Elasticsearc...
Jan 31 16:29:51 vm7502678699.bitcommand.com systemd[1]: Started Elasticsearch.
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: elasticsearch.service...
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: Unit elasticsearch.se...
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: elasticsearch.service...
Hint: Some lines were ellipsized, use -l to show in full.

and log

    Feb 01 03:13:51 vm7502678699.bitcommand.com kernel: Out of memory: Kill process 25119 (php-fpm) score 22 or sacrifice child
Feb 01 03:13:51 vm7502678699.bitcommand.com kernel: Killed process 25119 (php-fpm), UID 1001, total-vm:692896kB, anon-rss:122208kB, file-rss:536kB, shmem-rss:12632kB
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: elasticsearch.service: main process exited, code=killed, status=9/KILL
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: Unit elasticsearch.service entered failed state.
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: elasticsearch.service failed.
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: mariadb.service: main process exited, code=killed, status=9/KILL
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: Unit mariadb.service entered failed state.
Feb 01 03:13:50 vm7502678699.bitcommand.com systemd[1]: mariadb.service failed.
Feb 01 03:13:52 vm7502678699.bitcommand.com systemd[1]: Removed slice User Slice of magento.
Feb 01 03:13:55 vm7502678699.bitcommand.com systemd[1]: mariadb.service holdoff time over, scheduling restart.
Feb 01 03:13:56 vm7502678699.bitcommand.com systemd[1]: Stopped MariaDB 10.4.17 database server.

we have 6 gb ram i don`t know how can i fix this problem ?

What is in the Elasticsearch logs? How much memory does the host have? What else is running on that host and how much memory are those processes using? Which version of Elasticsearch are you using?

1-
last logs :

[2021-02-01T01:30:00,002][INFO ][o.e.x.m.MlDailyMaintenanceService] [vm7502678699.bitcommand.com] triggering scheduled [ML] maintenance tasks
[2021-02-01T01:30:00,057][INFO ][o.e.x.m.a.TransportDeleteExpiredDataAction] [vm7502678699.bitcommand.com] Deleting expired data
[2021-02-01T01:30:00,199][INFO ][o.e.x.m.j.r.UnusedStatsRemover] [vm7502678699.bitcommand.com] Successfully deleted [0] unused stats documents
[2021-02-01T01:30:00,201][INFO ][o.e.x.m.a.TransportDeleteExpiredDataAction] [vm7502678699.bitcommand.com] Completed deletion of expired ML data
[2021-02-01T01:30:00,203][INFO ][o.e.x.m.MlDailyMaintenanceService] [vm7502678699.bitcommand.com] Successfully completed [ML] maintenance task: triggerDeleteExpiredDataTask
[2021-02-01T02:30:00,033][INFO ][o.e.x.s.SnapshotRetentionTask] [vm7502678699.bitcommand.com] starting SLM retention snapshot cleanup task
[2021-02-01T02:30:00,047][INFO ][o.e.x.s.SnapshotRetentionTask] [vm7502678699.bitcommand.com] there are no repositories to fetch, SLM retention snapshot cleanup task complete

2-
6GB memory we have

3-
Magento 2.4 and In the worst case, 2 GB is in use

4-
Last version of elastic search 7.10.2

We'd need to see more of the Elasticsearch log, can you post the entire thing?

How much heap have you allocated to Elasticsearch? If you have 6GB in total available and all the other processes running on the host use 2GB I would probably start with a heap size of 1GB as Elasticsearch also requires off heap memory and memory for the operating system page cache.