CID-471: add mappings for ephemeral storages

devops-service/providers/ec2.rb

@@ -101,7 +101,8 @@ module Provider
 #        "Placement.AvailabilityZone" => s.options[:availability_zone],
         "KeyName" => self.ssh_key,
         "PrivateIpAddress" => s.private_ip,
-        "EbsOptimized" => ebs_optimized?(flavor)
+        "EbsOptimized" => ebs_optimized?(flavor),
+        "BlockDeviceMapping" => ephemeral_storages_mappings(flavor)
       }
       vpcId = nil
       unless subnets.empty?
@@ -413,9 +414,28 @@ module Provider
       end
     end
 
-    def ebs_optimized?(instance_type)
+    # When you create an instance with one of these flavors within AWS console,
+    # EbsOptimized is automatically set to true. But in case of creating within API we should set it manually.
+    def ebs_optimized?(flavor)
       always_ebs_optimized = ['c4.large', 'c4.xlarge', 'c4.2xlarge', 'c4.4xlarge', 'c4.8xlarge', 'd2.xlarge', 'd2.2xlarge', 'd2.4xlarge', 'd2.8xlarge', 'm4.large', 'm4.xlarge', 'm4.2xlarge', 'm4.4xlarge', 'm4.10xlarge']
-      always_ebs_optimized.include?(instance_type)
+      always_ebs_optimized.include?(flavor)
+    end
+
+    # 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.
+    def ephemeral_storages_mappings(flavor)
+      require 'fog/aws/models/compute/flavors'
+      details = Fog::Compute::AWS::FLAVORS.detect {|f| f[:id] == flavor}
+      return [] unless details
+
+      mappings = []
+      details[:instance_store_volumes].times do |i|
+        mappings << {
+          'VirtualName' => "ephemeral#{i}",
+          'DeviceName' => "/dev/xvd#{('b'.ord + i).chr}"
+        }
+      end
+      mappings
     end
 
   end