diff --git a/devops-service/lib/executors/server_executor.rb b/devops-service/lib/executors/server_executor.rb
index 6d488fb..79f78dc 100644
--- a/devops-service/lib/executors/server_executor.rb
+++ b/devops-service/lib/executors/server_executor.rb
@@ -37,7 +37,7 @@ module Devops
       define_hook :before_bootstrap
       define_hook :after_bootstrap
 
-      before_deploy :create_run_list
+      before_deploy :add_run_list_to_deploy_info
 
 
       attr_accessor :server, :deploy_env
@@ -471,7 +471,7 @@ module Devops
         end
       end
 
-      def create_run_list out, deploy_info
+      def add_run_list_to_deploy_info out, deploy_info
         out << "\nGenerate run list hook...\n"
         if deploy_info["run_list"]
           out << "Deploy info already contains 'run_list': #{deploy_info["run_list"].join(", ")}\n"
@@ -480,14 +480,6 @@ module Devops
         out << "Project run list: #{@project.run_list.join(", ")}\n"
         out << "Deploy environment run list: #{@deploy_env.run_list.join(", ")}\n"
         out << "Server run list: #{@server.run_list.join(", ")}\n"
-=begin
-        rlist = Set.new.merge(@deploy_env.provider_instance.run_list).merge(@project.run_list).merge(@deploy_env.run_list).merge(@server.run_list)
-        if @server.stack
-          stack = Devops::Db.connector.stack(@server.stack)
-          out << "Stack run list: #{stack.run_list.join(", ")}\n"
-          rlist.merge(stack.run_list)
-        end
-=end
         deploy_info["run_list"] = compute_run_list
         out << "New deploy run list: #{deploy_info["run_list"].join(", ")}\nRun list has been generated\n\n"
       end
@@ -495,16 +487,14 @@ module Devops
       def compute_run_list
         rlist = []
         [@deploy_env.provider_instance.run_list, @project.run_list, @deploy_env.run_list, @server.run_list].each do |sub_run_list|
-          rlist += sub_run_list if sub_run_list.is_a?(Array)
+          rlist += sub_run_list if sub_run_list
         end
-        rlist = Set.new(rlist)
         if @server.stack
           stack = Devops::Db.connector.stack(@server.stack)
-#          out << "Stack run list: #{stack.run_list.join(", ")}\n"
           srl = stack.run_list
-          rlist.merge(srl) if srl.is_a?(Array)
+          rlist += srl if srl
         end
-        rlist.to_a
+        rlist.uniq
       end
 
       private
diff --git a/devops-service/spec/executors/server_executor_spec.rb b/devops-service/spec/executors/server_executor_spec.rb
index a7ed918..2b7dbed 100644
--- a/devops-service/spec/executors/server_executor_spec.rb
+++ b/devops-service/spec/executors/server_executor_spec.rb
@@ -698,4 +698,53 @@ RSpec.describe Devops::Executor::ServerExecutor, type: :executor, stubbed_connec
     end
   end
 
+
+  describe '#add_run_list_to_deploy_info' do
+    it "doesn't change deploy info if it already includes run list" do
+      deploy_info = {'run_list' => %w(foo)}
+      expect {
+        executor.add_run_list_to_deploy_info(output, deploy_info)
+      }.not_to change { deploy_info }
+    end
+
+    it 'computes and adds run_list to deploy_info' do
+      deploy_info = {}
+      allow(executor).to receive(:compute_run_list) { %w(foo) }
+      expect(executor).to receive(:compute_run_list)
+      executor.add_run_list_to_deploy_info(output, deploy_info)
+      expect(deploy_info['run_list']).to eq %w(foo)
+    end
+  end
+
+  describe '#compute_run_list' do
+    before do
+      allow(deploy_env).to receive_message_chain('provider_instance.run_list') { %w(a) }
+      project.run_list = %w(b)
+      deploy_env.run_list = %w(c)
+      server.run_list = %w(d)
+    end
+
+    it "returns array with run list merged from provider's, project's, env's and server's run lists" do
+      expect(executor.compute_run_list).to be_an(Array).and contain_exactly(*%w(a b c d))
+    end
+
+    it "includes stack's run list if stack is set", stubbed_connector: true do
+      server.stack = 'stack'
+      allow(stubbed_connector).to receive(:stack) { instance_double(Devops::Model::StackEc2, run_list: %w(e)) }
+      expect(executor.compute_run_list).to be_an(Array).and contain_exactly(*%w(a b c d e))
+    end
+
+    it "doesn't contain nils" do
+      server.run_list = nil
+      server.stack = 'stack'
+      allow(stubbed_connector).to receive(:stack) { instance_double(Devops::Model::StackEc2, run_list: nil) }
+      expect(executor.compute_run_list).to be_an(Array).and contain_exactly(*%w(a b c))
+    end
+
+    it 'returns uniq elements' do
+      project.run_list = %w(a)
+      deploy_env.run_list = %w(a)
+      expect(executor.compute_run_list).to be_an(Array).and contain_exactly(*%w(a d))
+    end
+  end
 end
\ No newline at end of file