I stood up a digital ocean Ubuntu and went thru this twice. are they current ?
Dec 08 04:50:23 ubuntu-1gb-nyc3-01 systemd[1]: Started High-performance, schema-free document-oriented database.
Dec 08 04:50:23 ubuntu-1gb-nyc3-01 mongod[4778]: Unrecognized option: security
Dec 08 04:50:23 ubuntu-1gb-nyc3-01 mongod[4778]: try '/usr/bin/mongod --help' for more information
Dec 08 04:50:23 ubuntu-1gb-nyc3-01 systemd[1]: mongod.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
Dec 08 04:50:23 ubuntu-1gb-nyc3-01 systemd[1]: mongod.service: Unit entered failed state.
Dec 08 04:50:23 ubuntu-1gb-nyc3-01 systemd[1]: mongod.service: Failed with result 'exit-code'.
timotheus@ubuntu-1gb-nyc3-01:~$ sudo nano /etc/mongod.conf
timotheus@ubuntu-1gb-nyc3-01:~$
timotheus@ubuntu-1gb-nyc3-01:~$ sudo service mongod restart
timotheus@ubuntu-1gb-nyc3-01:~$ sudo service mongod status
ā mongod.service - High-performance, schema-free document-oriented database
Loaded: loaded (/lib/systemd/system/mongod.service; disabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Fri 2017-12-08 04:51:11 UTC; 5s ago
Docs: https://docs.mongodb.org/manual
Process: 4796 ExecStart=/usr/bin/mongod --quiet --config /etc/mongod.conf (code=exited, status=1/FAILURE)
Main PID: 4796 (code=exited, status=1/FAILURE)
Dec 08 04:51:11 ubuntu-1gb-nyc3-01 systemd[1]: Started High-performance, schema-free document-oriented database.
Dec 08 04:51:11 ubuntu-1gb-nyc3-01 mongod[4796]: 2017-12-08T04:51:11.714+0000 F CONTROL [main] Failed global initialization: BadValue: security.authorization must be a string of
Dec 08 04:51:11 ubuntu-1gb-nyc3-01 systemd[1]: mongod.service: Main process exited, code=exited, status=1/FAILURE
Dec 08 04:51:11 ubuntu-1gb-nyc3-01 systemd[1]: mongod.service: Unit entered failed state.
Dec 08 04:51:11 ubuntu-1gb-nyc3-01 systemd[1]: mongod.service: Failed with result 'exit-code'.
Can you share your mongod.conf? It sounds like a config option there isn't quite right.
