MongoDB service showing down but db is running

Question

I have a strange problem. I am using mongodb version 4.2.8 on Redhat Linux 7. Using Master Slave Replication. When I check mongodb service status (systemctl status mongod.service) it shows as failed(complete message mentioned below). But I can connect to db primary and slave and I can query , it is working. But why it shows as service as failed when I try to check using systemctl status mongod.service command.

[mongod@bsbdigchdb01 ~]$ systemctl status mongod.service ● mongod.service - MongoDB Database Server Loaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled) Active: failed (Result: exit-code) since Wed 2020-06-24 03:21:19 IDT; 3 weeks 0 days ago Docs: https://docs.mongodb.org/manual Process: 2458 ExecStart=/usr/bin/mongod $OPTIONS (code=exited, status=2) Process: 2454 ExecStartPre=/usr/bin/chmod 0755 /var/run/mongodb (code=exited, status=0/SUCCESS) Process: 2449 ExecStartPre=/usr/bin/chown mongod:mongod /var/run/mongodb (code=exited, status=0/SUCCESS) Process: 2447 ExecStartPre=/usr/bin/mkdir -p /var/run/mongodb (code=exited, status=0/SUCCESS) Main PID: 8482 (code=exited, status=0/SUCCESS)

Jun 24 03:21:19 bsbdigchdb01 systemd[1]: Starting MongoDB Database Server... Jun 24 03:21:19 bsbdigchdb01 mongod[2458]: Error opening config file: Is a directory Jun 24 03:21:19 bsbdigchdb01 systemd[1]: mongod.service: control process exited, code=exited status=2 Jun 24 03:21:19 bsbdigchdb01 systemd[1]: Failed to start MongoDB Database Server. Jun 24 03:21:19 bsbdigchdb01 systemd[1]: Unit mongod.service entered failed state. Jun 24 03:21:19 bsbdigchdb01 systemd[1]: mongod.service failed.

But when I ps -ef |grep mongod it displays running process. [mongod@bsbdigchdb01 ~]$ ps -ef |grep mongod mongod 2539 1 0 Jun24 ? 02:56:55 mongod -f /etc/mongodb1/mongod.conf mongod 7352 1 0 Apr07 ? 11:28:57 mongod -f /etc/mongodb2/mongod.conf