Based upon John Byrne's chef_workflow_terraform cookbook
This cookbook provisions multiple nodes within AWS via terraform. It is called from a Chef Automate build_cookboook
Once the AWS attribtues are set, the primary attribute is:
default['delivery_provision_aws']['provision']['0'] = { 'platform' => 'ubuntu-14.04', 'size' => 't2.micro', 'recipe' => 'default' }
There can be multiple values, just increament the digit, the recipe loops through them.
This also allows for running of a non-default recipe. Perhaps your cookbook has both a client and server recipes that do different things, well that can be specied like:
default['delivery_provision_aws']['provision']['0'] = { 'platform' => 'ubuntu-14.04', 'size' => 't2.micro', 'recipe' => 'client' }
default['delivery_provision_aws']['provision']['0'] = { 'platform' => 'ubuntu-16.04', 'size' => 't2.micro', 'recipe' => 'server' }
Each node can be a different platform, size and recipe. The cookbooks writes terraform tf files and then combines them all into a single parallel execution.