Configuration

While well-behaved Vagrant providers should work with any Vagrantfile with sane defaults, providers generally expose unique configuration options so that you can get the most out of each provider.

This provider-specific configuration is done within the Vagrantfile in a way that is portable, easy to use, and easy to understand.

Portability

An important fact is that even if you configure other providers within a Vagrantfile, the Vagrantfile remains portable even to individuals who do not necessarily have that provider installed.

For example, if you configure VMware Fusion and send it to an individual who does not have the VMware Fusion provider, Vagrant will silently ignore that part of the configuration.

Provider Configuration

Configuring a specific provider looks like this:

Vagrant.configure("2") do |config|
  # ...

  config.vm.provider "virtualbox" do |vb|
    vb.customize ["modifyvm", :id, "--cpuexecutioncap", "50"]
  end
end

Multiple config.vm.provider blocks can exist to configure multiple providers.

The configuration format should look very similar to how provisioners are configured. The config.vm.provider takes a single parameter: the name of the provider being configured. Then, an inner block with custom configuration options is exposed that can be used to configure that provider.

This inner configuration differs among providers, so please read the documentation for your provider of choice to see available configuration options.

Remember, some providers do not require any provider-specific configuration and work directly out of the box. Provider-specific configuration is meant as a way to expose more options to get the most of the provider of your choice. It is not meant as a roadblock to running against a specific provider.

Overriding Configuration

Providers can also override non-provider specific configuration, such as config.vm.box and any other Vagrant configuration. This is done by specifying a second argument to config.vm.provider. This argument is just like the normal config, so set any settings you want, and they will be overridden only for that provider.

Example:

Vagrant.configure("2") do |config|
  config.vm.box = "precise64"

  config.vm.provider "vmware_fusion" do |v, override|
    override.vm.box = "precise64_fusion"
  end
end

In the above case, Vagrant will use the "precise64" box by default, but will use "precise64_fusion" if the VMware Fusion provider is used.

The Vagrant Way: The proper "Vagrant way" is to avoid any provider-specific overrides if possible by making boxes for multiple providers that are as identical as possible, since box names can map to multiple providers. However, this is not always possible, and in those cases, overrides are available.