Failed to start mongod.service: Unit mongod.service not found

Question

I follow all the steps mention in MongoDB installation documents for Ubuntu 16.04.

Steps 1:

sudo apt-key adv --keyserv         


        

Answer 1

Well.... My answer may be considered naive but in fact it has been the only way MongoDB has work in my case, Ubuntu 19.10. I tried to run the commands from the most voted comments and none worked, when running:

mongod --repair

I got this alert:

With some research I found out that running the DB in another port could be a solution, then:

mongod --port 27018

And it works great for me every time. Long answer but wanted to give context before giving such a simple solution.

(If I'm doing it wrong or doesn't seem logical, plz tell me! Relevant for me)