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

In some cases for some security reasons the unit would be marked as masked. This state is much stronger than being disabled in which you cannot even start the service manually.

to check this, run the following command:

    systemctl list-unit-files | grep mongod

if you find out something like this:

    mongod.service                         masked

then you can unmask the unit by:

    sudo systemctl unmask mongod

then you may want to start the service:

    sudo systemctl start mongod

and to enable auto-start during system boot:

    sudo systemctl enable mongod

However if mongodb did not start again or was not masked at all, you have the option to reinstall it this way:

    sudo apt-get --purge mongo*
    sudo apt-get install mongodb-org

thanks to @jehanzeb-malik

Answer 2

The second step of mongo installation is

echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.4 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.4.list

Instead of this command do it manually

1. cd /etc/apt/
2. nano sources.list
3. Write it deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.4 multiverse

And save the file,

Continue all process as in installation docs

It works for me:

Answer 3

Just try with this command:

$ sudo systemctl enable mongod

Answer 4

For those that run into this and end up on this answer, as I did, where they got this error during uninstall orupgrade and Ubuntu keeps failing to uninstall the previous because the service doesn't exist this one line will get you past that and allow the uninstall or upgrade to continue.

sudo touch /lib/systemd/system/mongod.service

Answer 5

$service mongodb start
$service mongodb status

the status is active when I started using above command

Answer 6

[Solution]

Just type

sudo mongod

It will work.