This is the output of the command you provided, please help me understand this..
[root@localhost ~]# dmesg|grep -E "kill|httpd|apache|http|mysql|oom"
[ 0.000000] Specific versions of hardware are certified with Red Hat Enterpri se Linux 8. Please see the list of hardware certified with Red Hat Enterprise Li nux 8 at https://catalog.redhat.com.
[ 162.905182] rfkill: input handler disabled
[root@localhost ~]# grep -i 'killed' /var/log/messages
Sep 11 11:19:23 localhost kernel: Out of memory: Killed process 2299 (redis-serv er) total-vm:2117948kB, anon-rss:1174444kB, file-rss:0kB, shmem-rss:0kB, UID:100 4 pgtables:4116kB oom_score_adj:0
Sep 11 12:42:09 localhost kernel: Out of memory: Killed process 12352 (redis-ser ver) total-vm:2118016kB, anon-rss:1066684kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:4116kB oom_score_adj:0
Sep 11 12:42:11 localhost kernel: Out of memory: Killed process 15535 (redis-ser ver) total-vm:2118412kB, anon-rss:1125284kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:4112kB oom_score_adj:0
Sep 11 12:54:20 localhost kernel: Out of memory: Killed process 16006 (redis-ser ver) total-vm:2118032kB, anon-rss:1031772kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:4120kB oom_score_adj:0
Sep 11 12:56:17 localhost kernel: Out of memory: Killed process 17084 (redis-ser ver) total-vm:2118320kB, anon-rss:1298696kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:4120kB oom_score_adj:0
Sep 11 13:41:35 localhost kernel: Out of memory: Killed process 20939 (redis-ser ver) total-vm:2117936kB, anon-rss:1483772kB, file-rss:736kB, shmem-rss:0kB, UID: 1004 pgtables:4116kB oom_score_adj:0
Sep 11 13:46:43 localhost kernel: Out of memory: Killed process 24752 (redis-ser ver) total-vm:1777832kB, anon-rss:1443068kB, file-rss:20kB, shmem-rss:0kB, UID:1 004 pgtables:3364kB oom_score_adj:0
Sep 11 13:47:31 localhost kernel: Out of memory: Killed process 25065 (redis-ser ver) total-vm:2117800kB, anon-rss:1864012kB, file-rss:68kB, shmem-rss:0kB, UID:1 004 pgtables:3864kB oom_score_adj:0
Sep 11 13:53:26 localhost kernel: Out of memory: Killed process 25898 (redis-ser ver) total-vm:2117800kB, anon-rss:1793496kB, file-rss:1412kB, shmem-rss:0kB, UID :1004 pgtables:3620kB oom_score_adj:0
Sep 11 13:53:45 localhost kernel: Out of memory: Killed process 26175 (redis-ser ver) total-vm:2117800kB, anon-rss:1916428kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:3844kB oom_score_adj:0
Sep 11 13:54:54 localhost kernel: Out of memory: Killed process 26381 (redis-ser ver) total-vm:1777832kB, anon-rss:1614804kB, file-rss:4kB, shmem-rss:0kB, UID:10 04 pgtables:3256kB oom_score_adj:0
Sep 11 14:01:23 localhost kernel: Out of memory: Killed process 27083 (redis-ser ver) total-vm:1777832kB, anon-rss:1576408kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:3192kB oom_score_adj:0
Sep 11 14:44:46 localhost kernel: Out of memory: Killed process 34159 (redis-ser ver) total-vm:2511548kB, anon-rss:1416956kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:4132kB oom_score_adj:0
Sep 11 14:44:47 localhost kernel: Out of memory: Killed process 33597 (redis-ser ver) total-vm:2511160kB, anon-rss:1416848kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:4132kB oom_score_adj:0
Sep 11 14:50:07 localhost kernel: Out of memory: Killed process 34853 (redis-ser ver) total-vm:2117800kB, anon-rss:1580788kB, file-rss:0kB, shmem-rss:0kB, UID:10 04 pgtables:4072kB oom_score_adj:0
Sep 11 15:22:09 localhost kernel: Out of memory: Killed process 2519 (redis-serv er) total-vm:2118072kB, anon-rss:803844kB, file-rss:68kB, shmem-rss:0kB, UID:100 4 pgtables:4116kB oom_score_adj:0