Vagrant, how to specify the disk size?

I have used the vagrant plugin vagrant-disksize to resize the disk.

It worked. It can also help to specify the initial disk size.

Run the following at the command line:

vagrant plugin install vagrant-disksize

and use the following in your Vagrantfile:

vagrant.configure('2') do |config|
    config.vm.box = 'ubuntu/xenial64'
    config.disksize.size="50GB"
end