cat /etc/mongod.conf
# mongo.conf

#where to log
logpath=/export/home/mongo/DB1/log/mongoDB1.log

logappend=true

# fork and run in background
fork = true

#port = 27017

dbpath=/export/home/mongo/DB1/data

# location of pidfile
pidfilepath = /export/home/mongo/DB1/mongodDB1.pid

[root@localhost ~]# service mongod start
Starting mongod (via systemctl):



Job failed. See system journal and 'systemctl status' for details.
                                                           [FAILED]

[root@localhost ~]# ps -ef | grep mongo
mongod    1036     1  0 03:05 ?        00:00:01 /usr/bin/mongod -f /etc/mongod.conf
root      1121  1049  0 03:12 pts/1    00:00:00 grep --color=auto mongo

Apr 23 03:05:52 localhost mongod[1028]: Starting mongod: Tue Apr 23 03:05:52.466
Apr 23 03:05:52 localhost mongod[1028]: Tue Apr 23 03:05:52.467 warning: 32-bit servers don't have journaling enabled by default. Please use --journal if you want durability.
Apr 23 03:05:52 localhost mongod[1028]: Tue Apr 23 03:05:52.468
Apr 23 03:05:52 localhost mongod[1028]: about to fork child process, waiting until server is ready for connections.
Apr 23 03:05:52 localhost mongod[1028]: forked process: 1036
Apr 23 03:05:52 localhost mongod[1028]: all output going to: /export/home/mongo/DB1/log/mongoDB1.log
Apr 23 03:05:52 localhost mongod[1028]: child process started successfully, parent exiting
Apr 23 03:05:52 localhost mongod[1028]: [  OK  ]

Apr 23 03:05:52 localhost systemd[1]: PID file /var/run/mongo/mongod.pid not readable (yet?) after start.