Zabbix agent version: Zabbix 3.4.11
OS : Linux x86_64
Zabbix agent status:
Previous status:
[root@locateevmp01 ~]# service zabbix-agent status
Redirecting to /bin/systemctl status zabbix-agent.service
● zabbix-agent.service - Zabbix Agent
Loaded: loaded (/usr/lib/systemd/system/zabbix-agent.service; enabled; vendor preset: disabled)
Active: active (running) since Wed 2019-04-10 11:03:16 EDT; 4 days ago
Process: 29548 ExecStop=/bin/kill -SIGTERM $MAINPID (code=exited, status=0/SUCCESS)
Process: 29551 ExecStart=/usr/sbin/zabbix_agentd -c $CONFFILE (code=exited, status=0/SUCCESS)
Main PID: 29553 (zabbix_agentd)
CGroup: /system.slice/zabbix-agent.service
├─29553 /usr/sbin/zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf
├─29554 /usr/sbin/zabbix_agentd: collector [idle 1 sec]
├─29555 /usr/sbin/zabbix_agentd: listener #1 [waiting for connection]
├─29556 /usr/sbin/zabbix_agentd: listener #2 [waiting for connection]
├─29557 /usr/sbin/zabbix_agentd: listener #3 [waiting for connection]
├─29558 /usr/sbin/zabbix_agentd: active checks #1 [idle 1 sec]
└─29559 /usr/sbin/zabbix_agentd: active checks #2 [idle 1 sec]

Apr 10 11:03:16 locateevmp01 systemd[1]: Starting Zabbix Agent...
Apr 10 11:03:16 locateevmp01 systemd[1]: zabbix-agent.service: Supervising process 29553 which is not our child. We'll most likely no...t exits.
Apr 10 11:03:16 locateevmp01 systemd[1]: Started Zabbix Agent.

After Restart:
[root@locateevmp01 ~]# service zabbix-agent status
Redirecting to /bin/systemctl status zabbix-agent.service
● zabbix-agent.service - Zabbix Agent
Loaded: loaded (/usr/lib/systemd/system/zabbix-agent.service; enabled; vendor preset: disabled)
Active: active (running) since Thu 2019-05-09 08:06:35 EDT; 12min ago
Process: 28076 ExecStop=/bin/kill -SIGTERM $MAINPID (code=exited, status=0/SUCCESS)
Process: 28095 ExecStart=/usr/sbin/zabbix_agentd -c $CONFFILE (code=exited, status=0/SUCCESS)
Main PID: 28097 (zabbix_agentd)
CGroup: /system.slice/zabbix-agent.service
├─28097 /usr/sbin/zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf
├─28098 /usr/sbin/zabbix_agentd: collector [idle 1 sec]
├─28099 /usr/sbin/zabbix_agentd: listener #1 [waiting for connection]
├─28100 /usr/sbin/zabbix_agentd: listener #2 [waiting for connection]
├─28101 /usr/sbin/zabbix_agentd: listener #3 [waiting for connection]
├─28102 /usr/sbin/zabbix_agentd: active checks #1 [idle 1 sec]
└─28103 /usr/sbin/zabbix_agentd: active checks #2 [idle 1 sec]

May 09 08:06:35 locateevmp01 systemd[1]: Starting Zabbix Agent...
May 09 08:06:35 locateevmp01 systemd[1]: Started Zabbix Agent.

Issue: systemd[1]: zabbix-agent.service: Supervising process 29553 which is not our child. We'll most likely no...t exits.
This error is reoccurring after sometime. Zabbix Agent is running with error.