diff --git a/devops-service/lib/stack_template_presets/base.rb b/devops-service/lib/stack_template_presets/base.rb
index 784a0ab..90ec310 100644
--- a/devops-service/lib/stack_template_presets/base.rb
+++ b/devops-service/lib/stack_template_presets/base.rb
@@ -17,7 +17,7 @@ module Devops
         stack_template_attrs = {
           id: stack_template_id,
           provider: provider,
-          template_body: serialize(actual_template_hash(template_preset_hash, template_attrs))
+          template_body: serialize(actual_template_hash(template_attrs))
         }
         template_model = Model::StackTemplateFactory.create(provider, stack_template_attrs)
       end
@@ -36,8 +36,42 @@ module Devops
         unserialize(template_preset_body)
       end
 
-      def actual_template_hash(template_preset_hash, params)
+      def actual_template_hash(template_attrs)
+        actual = template_preset_body.dup
+        template_attrs.each do |key, value|
+          path = param_attrs_pathes_in_preset[key.to_sym]
+          next unless path
+          insert_value_at(actual, value, path)
+        end
+        actual
+      end
 
+      # returns hash with keys lists. Better to show an example:
+      # Imagine tha t template is the following:
+      # {
+      #   template: {
+      #     users_count: %users_count%
+      #   }
+      # }
+      #
+      # So param_attrs_pathes_in_preset will be
+      # {users_count: [:template, :users_count]}
+      def param_attrs_pathes_in_preset
+        {}
+      end
+
+      # given hash = {t: {a: nil}}, value = 1, path = [:t, :a] returns
+      # {t: {a: 1}}
+      def insert_value_at(hash, value, path)
+        current = hash
+        path.each_with_index do |key, i|
+          if i == path.size - 1
+            current[key] = value
+          else
+            current = current[key]
+          end
+        end
+        hash
       end
 
       # some templates may be YAML files
diff --git a/devops-service/routes/v2.0/handlers/stack_template_preset.rb b/devops-service/routes/v2.0/handlers/stack_template_preset.rb
index a519a77..666dbae 100644
--- a/devops-service/routes/v2.0/handlers/stack_template_preset.rb
+++ b/devops-service/routes/v2.0/handlers/stack_template_preset.rb
@@ -20,7 +20,7 @@ module Devops
           }
         end
 
-        def build_stack_template
+        def self.build_stack_template
           lamda {
             # check_privileges("stack_template_presets", "r")
             check_privileges('stack_template', 'w')