Reload the local Ubuntu package database

Ubuntu 14.04:

sudo apt-get update

Ubuntu 16.04:

sudo apt update

Start the install for MongoDB

Ubuntu 14.04:

sudo apt-get install -y mongodb-org

Ubuntu 16.04:

sudo apt install -y mongodb-org

MongoDB Installation Progress

Now to start MongoDB with systemctl.

sudo systemctl start mongod

Originally tested using MongoDB 3.26 on Ubuntu 14.04

Updated and tested using MongoDB 3.6 on Ubuntu 16.04