### Problem: I installed MongoDB using the official method but now I need to secure it via username/password
####Environment: MongoDB Enterprise 3.4 on Ubuntu 16.04

**Solution** (there is more than 1 way, but this is the one I prefer):

*Step 1 - Create username/password:*

Start mongo shell

    mongo

Create a new user in admin database

	use admin
	db.createUser(
	  {
	    user: "myUserAdmin",
	    pwd: "abc123",
	    roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
	  }
	)

Stop the DB service

	sudo service mongod stop
	sudo vim /etc/mongod.conf

In mongod.conf file, uncomment this line, so it looks like this:

	security:
	  authorization: 'enabled'

Start the service

	sudo service mongod start

Start the shell and run a query, you should see an error:

	MongoDB Enterprise > show databases
	...
	listDatabases failed:{
		"ok" : 0,
		"errmsg" : "not authorized on admin to execute
		 command { listDatabases: 1.0 }",
	...
Open the shell, this time with the correct username and password:

	mongo -u myUserAdmin --authenticationDatabase=admin -p abc123

It should work this time

MongoDB Enterprise > show databases
admin  0.000GB
local  0.000GB