As long as Lightsail doesn't limit the capabilities of their VPS, I don't see why it would be any different from a normal install on Ubuntu.
yeah, it's identical. LightSail ends up being exactly like a DO or Vultr.
Typo in MongoDB installation
" nano /etc/mongodb.conf " should be "nano /etc/mongod.conf"
"service mongodb restart" should be "service mongod restart"
I think it might be an OS thing: http://stackoverflow.com/questions/11600006/how-to-create-a-configuration-file-for-mongodb
If you install mongo via apt, I believe it is
mongod, but via the 10gen repository, it is