link

So I had to write one from scratch. To create one of your own follow these steps:

1. switch to root using

   sudo su
   

or use sudo for all the following steps.

2. create a service script (in this example the name of the service is Mongodb)

   nano /lib/systemd/system/mongodb.service
   

3. File content should be

   [Unit]
   Description=MongoDB Database Service
   Wants=network.target
   After=network.target
   
   [Service]
   ExecStart=/usr/bin/mongod --config /etc/mongod.conf
   ExecReload=/bin/kill -HUP $MAINPID
   Restart=always
   User=mongodb
   Group=mongodb
   StandardOutput=syslog
   StandardError=syslog
   
   [Install]
   WantedBy=multi-user.target
   

You can also download the file from here: mongodb.service
Here is a quick description of the important fields:
ExecStart - Is the command to run. Mongo installs itself under /usr/bin and the configuration file is written at /etc
User - The uid of the mongod process.
Group - The gid of the mongod process. Note that the user and group are created by the installation.

Now to start mongodb:

sudo systemctl start mongodb

To stop mongodb service use:

sudo systemctl stop mongodb

To enable mongodb on startup

sudo systemctl enable mongodb.service

If you need to refresh the services use:

 sudo systemctl daemon-reload