MongoDB isn't starting in ubuntu 16.04 - mongodb

Question

I setup mongodb on ubuntu 16.04 with:
echo "deb http://repo.mongodb.org/apt/debian wheezy/mongodb-org/3.0 main" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list
sudo apt-get update
sudo apt-get install -y mongodb-org
But I get these error when i try to start the service:
**~$** systemctl start mongodb
Failed to start mongodb.service: Unit mongodb.service is masked.
**~$** systemctl start mongod
Failed to start mongod.service: Unit mongod.service not found.
**~$** sudo service mongod start
Failed to start mongod.service: Unit mongod.service not found.
**~$** mongod
mongod --help for help and startup options
2016-09-04T11:20:59.074+0200 [initandlisten] MongoDB starting : pid=30207 port=27017 dbpath=/data/db 64-bit host=zantes
2016-09-04T11:20:59.074+0200 [initandlisten] db version v2.6.10
2016-09-04T11:20:59.074+0200 [initandlisten] git version: nogitversion
2016-09-04T11:20:59.074+0200 [initandlisten] OpenSSL version: OpenSSL 1.0.2g-fips 1 Mar 2016
2016-09-04T11:20:59.074+0200 [initandlisten] build info: Linux lgw01-12 3.19.0-25-generic #26~14.04.1-Ubuntu SMP Fri Jul 24 21:16:20 UTC 2015 x86_64 BOOST_LIB_VERSION=1_58
2016-09-04T11:20:59.074+0200 [initandlisten] allocator: tcmalloc
2016-09-04T11:20:59.074+0200 [initandlisten] options: {}
2016-09-04T11:20:59.074+0200 [initandlisten] exception in initAndListen: 10296
*********************************************************************
ERROR: dbpath (/data/db) does not exist.
Create this directory or give existing directory in --dbpath.
See http://dochub.mongodb.org/core/startingandstoppingmongo
*********************************************************************
, terminating
2016-09-04T11:20:59.074+0200 [initandlisten] dbexit:
2016-09-04T11:20:59.074+0200 [initandlisten] shutdown: going to close listening sockets...
2016-09-04T11:20:59.074+0200 [initandlisten] shutdown: going to flush diaglog...
2016-09-04T11:20:59.074+0200 [initandlisten] shutdown: going to close sockets...
2016-09-04T11:20:59.074+0200 [initandlisten] shutdown: waiting for fs preallocator...
2016-09-04T11:20:59.074+0200 [initandlisten] shutdown: lock for final commit...
2016-09-04T11:20:59.074+0200 [initandlisten] shutdown: final commit...
2016-09-04T11:20:59.074+0200 [initandlisten] shutdown: closing all files...
2016-09-04T11:20:59.074+0200 [initandlisten] closeAllFiles() finished
2016-09-04T11:20:59.074+0200 [initandlisten] dbexit: really exiting now
But when i check the status is active, please help me. I don't know what I have to do!
**~$** sudo systemctl status mongodb
**●** mongodb.service - An object/document-oriented database
Loaded: loaded (/lib/systemd/system/mongodb.service; enabled; vendor prese
Active: active (running) since dom 2016-09-04 11:01:11 CEST; 20min ago
Docs: man:mongod(1)
Main PID: 27544 (mongod)
CGroup: /system.slice/mongodb.service
└─27544 /usr/bin/mongod --config /etc/mongodb.conf
set 04 11:01:11 zantes systemd[1]: Started An object/document-oriented databa
lines 1-9/9 (END)
I previously worked on c9 but it has so much problems and is slow, I need mongodb for working on my projects
(sorry for my bad englis)

Answer 1

Somewhere in the error message it says "dbpath (/data/db) does not exist". "/data/db" is the default directory in which mongodb stores its data files. You have to create it manually. It seems this path does not exist.
If you want to change this path, either pass --dbpath parameter to mongod or change the dbpath parameter value in mongodb.conf file.

Answer 2

if mongodbversion is >=4 and installed in ubuntu, use mongod instead of mongodb
sudo systemctl status mongod
sudo systemctl start mongod
sudo vi /etc/mongod.conf
otherwise , you will get following error with mongodb command
Failed to restart mongodb.service: Unit mongodb.service is masked.