Here is what I found in the audit log:
on Centos 7:
type=SERVICE_START msg=audit(06/25/2020 15:24:18.967:80755) : pid=1 uid=root auid=unset
ses=unset msg='unit=systemd-shutdownd comm=systemd exe=/usr/lib/systemd/systemd
hostname=? addr=? terminal=? res=success'
type=SYSTEM_RUNLEVEL msg=audit(06/25/2020 15:25:19.501:103256) : user pid=12951 uid=root
auid=unset ses=unset msg='old-level=3 new-level=0 exe=/sbin/shutdown hostname=? addr=?
terminal=? res=success'
----
type=SYSTEM_SHUTDOWN msg=audit(06/25/2020 15:25:19.501:103257) : user pid=12951 uid=root
auid=unset ses=unset msg='init exe=/sbin/shutdown hostname=? addr=? terminal=?
res=success'
=============================================================
on Centos 6:
[root@aries ~]# ausearch -i -p 12951
----
type=USER_AUTH msg=audit(05/23/2020 20:23:44.890:8878) : user pid=12951 uid=ovirtagent
auid=unset ses=unset msg='op=PAM:authentication acct=ovirtagent
exe=/usr/sbin/userhelper hostname=? addr=? terminal=? res=success'
----
type=USER_ACCT msg=audit(05/23/2020 20:23:44.891:8879) : user pid=12951 uid=ovirtagent
auid=unset ses=unset msg='op=PAM:accounting acct=ovirtagent exe=/usr/sbin/userhelper
hostname=? addr=? terminal=? res=success'
----
type=SYSTEM_RUNLEVEL msg=audit(06/25/2020 15:25:19.501:103256) : user pid=12951 uid=root
auid=unset ses=unset msg='old-level=3 new-level=0 exe=/sbin/shutdown hostname=? addr=?
terminal=? res=success'
----
type=SYSTEM_SHUTDOWN msg=audit(06/25/2020 15:25:19.501:103257) : user pid=12951 uid=root
auid=unset ses=unset msg='init exe=/sbin/shutdown hostname=? addr=? terminal=?
res=success'
----