@qgp9 I can't say exactly how I installed Mongo. When I google, "ubuntu install mongo", my web browser tells me that this page
has been visited and it looks familiar. I think it's what I used to guide me.
And, no, I did not compile. And no, I am not using docker.
A detail, since you seem to be interested, is that the install does not leave my system with a functioning "service mongod restart" command. At present, Upstart runs Mongo. "stop mongod" does not work.