CID-471: add docs

devops-service/providers/ec2.rb

@@ -423,6 +423,7 @@ module Provider
 
     # When you create an instance with with ephemeral storages available within AWS console,
     # they are mapped automatically. But in case of creating within API we should map them manually.
+    # Result example: [{'VirtualName' => 'ephemeral0', 'DeviceName' => '/dev/xvdb'}]
     def ephemeral_storages_mappings(flavor)
       require 'fog/aws/models/compute/flavors'
       details = Fog::Compute::AWS::FLAVORS.detect {|f| f[:id] == flavor}