You need to manually install mongodb for anything above Ubuntu 16 (I think)
These are my steps for putting it on Ubuntu 20 :
sudo apt install -y mongodb
then check if its running :
sudo systemctl status mongodb
Edit the mongodb conf to bind the Deadline repository ip address
sudo nano /etc/mongodb.conf
Bind_ip = 127.0.0.1,192.168.xx.xx <--this is your deadline ip
port = 27017 <-- this is the port deadline will look for
Save and exit the file.
Restart the mongodb service with
sudo systemctl restart mongodb
Check it still works with
sudo status systemctl mongodb
Then when it comes to installing deadline, use an existing mongo database and make sure the port is correct and it “should” work.