You can set the VAGRANT_DEFAULT_PROVIDER
environment variable (docs). For example in .profile or alike:
export VAGRANT_DEFAULT_PROVIDER="vmware_fusion"
If you want to set it for a specific project, you should be able to set it in Vagrantfile:
ENV['VAGRANT_DEFAULT_PROVIDER'] = "vmware_fusion"
Vagrant.configure('2') do |config|
# ...
end
The provider can be overridden with the CLI option.