Message: TypeError: no implicit conversion of nil into String

[NachoLibre]

I get the following error for Vagrant standalone mode:

There was an error loading a Vagrantfile. The file being loaded
and the error message are shown below. This is usually caused by
a syntax error.

Path: <provider config: virtualbox>
Line number: 98
Message: TypeError: no implicit conversion of nil into String

it looks like changing the line in Vagrantfile-standalone in line 98 fixes the issue

vb.name = 'coreos-mesos-' + node[:hostname]

change to

vb.name = 'coreos-mesos-' + node['hostname']

I will crate PR for that