diff --git a/devops-service/lib/executors/stack_executor.rb b/devops-service/lib/executors/stack_executor.rb
index 9a3dd9a..2cae103 100644
--- a/devops-service/lib/executors/stack_executor.rb
+++ b/devops-service/lib/executors/stack_executor.rb
@@ -15,7 +15,7 @@ module Devops
       def initialize(options)
         @out = options.fetch(:out)
         @stack = options[:stack]
-        self.just_persisted_by_priority = {}
+        @just_persisted_by_priority = {}
       end
 
       def create_stack(stack_attrs)
@@ -31,33 +31,45 @@ module Devops
       end
 
       def persist_new_servers
-        reload_stack
-        raise 'It seems that stack is synchronizing at the moment' if stack.persisting_is_locked
-        begin
-          stack.lock_persisting!
-          fetcher.new_servers_by_priorities.each do |priority, provider_infos|
-            servers = provider_infos.map {|info| persister.persist(info) }
-            just_persisted_by_priority[priority] = servers
-          end
-
-          just_persisted_by_priority.values.flatten.each do |server|
-            puts_and_flush "\n\nPersisted server #{server.id}: #{JSON.pretty_generate(server.to_hash)}"
-          end
-        ensure
-          stack.unlock_persisting!
+        fetcher.reset_states
+        servers_to_persist = fetcher.servers_to_persist
+        if servers_to_persist.any?
+          out.puts 'Servers to persist:'
+          servers_to_persist.each { |info| out.puts JSON.pretty_generate(info) }
+          puts_and_flush "\n\nPersisting new servers:"
+        else
+          puts_and_flush 'There are no servers to persist.'
+          return
         end
+
+        fetcher.new_servers_by_priorities.each do |priority, provider_infos|
+          servers = provider_infos.map {|info| persister.persist(info) }
+          @just_persisted_by_priority[priority] = servers
+        end
+        puts_and_flush "New servers have been persisted"
       end
 
       def bootstrap_just_persisted(jid)
-        puts_and_flush "Bootstrapping just persisted servers" if just_persisted_by_priority.values.flatten.any?
-        just_persisted_by_priority.each do |priority, servers|
+        puts_and_flush "Bootstrapping just persisted servers" if @just_persisted_by_priority.values.flatten.any?
+        @just_persisted_by_priority.each do |priority, servers|
           puts_and_flush "Servers with priority '#{priority}': #{servers.map(&:id).join(", ")}"
         end
-        PrioritizedGroupsBootstrapper.new(out, jid, just_persisted_by_priority).bootstrap_servers_by_priority
+        PrioritizedGroupsBootstrapper.new(out, jid, @just_persisted_by_priority).bootstrap_servers_by_priority
       end
 
       def delete_stale_servers
-        fetcher.stale_servers.each do |server|
+        fetcher.reset_states
+        servers_to_delete = fetcher.stale_servers
+        if servers_to_delete.any?
+          out.puts "\nStale servers:"
+          servers_to_delete.each { |server| out.puts JSON.pretty_generate(server.to_hash) }
+          puts_and_flush 'Deleting stale servers.'
+        else
+          puts_and_flush "\nThere are no stale servers."
+          return
+        end
+
+        servers_to_delete.each do |server|
           proper_remove_server(server)
         end
       end
@@ -76,8 +88,6 @@ module Devops
 
       private
 
-      attr_accessor :just_persisted_by_priority
-
       def mongo
         Devops::Db.connector
       end
@@ -91,10 +101,6 @@ module Devops
         end
       end
 
-      def reload_stack
-        @stack = mongo.stack(@stack.name)
-      end
-
       def fetcher
         @fetcher ||= StackServersFetcher.new(stack, out)
       end
diff --git a/devops-service/lib/executors/stack_executor/stack_servers_fetcher.rb b/devops-service/lib/executors/stack_executor/stack_servers_fetcher.rb
index 6df318f..c7ab48a 100644
--- a/devops-service/lib/executors/stack_executor/stack_servers_fetcher.rb
+++ b/devops-service/lib/executors/stack_executor/stack_servers_fetcher.rb
@@ -36,23 +36,7 @@ class Devops::Executor::StackExecutor
       @by_state[STALE]
     end
 
-    private
-
-    def fetch
-      @servers_info = @stack.provider_instance.stack_servers(@stack)
-      divide_into_states
-      output_fetched_servers
-    end
-
-    def priority_from_info(provider_info)
-      if provider_info['tags']
-        priority = provider_info['tags']['cid:priority'].to_i
-      else
-        0
-      end
-    end
-
-    def divide_into_states
+    def set_states
       persisted = Devops::Db.connector.stack_servers(@stack.name)
       persisted_ids = persisted.map(&:id)
       in_cloud_ids = @servers_info.map {|info| info['id']}
@@ -69,29 +53,21 @@ class Devops::Executor::StackExecutor
 
       @by_state[STALE] = persisted.select { |server| deleted_ids.include?(server.id) }
     end
+    alias_method :reset_states, :set_states
 
-    # Do not move it to stack executor till set events handling properly.
-    # For now there may be already persisted servers on creation because of too early events from aws.
-    def output_fetched_servers
-      if servers_to_persist.any?
-        out.puts 'Servers to persist:'
-        servers_to_persist.each { |info| out.puts JSON.pretty_generate(info) }
+    private
+
+    def fetch
+      @servers_info = @stack.provider_instance.stack_servers(@stack)
+      reset_states
+    end
+
+    def priority_from_info(provider_info)
+      if provider_info['tags']
+        priority = provider_info['tags']['cid:priority'].to_i
       else
-        out.puts 'There are no servers to persist.'
+        0
       end
-
-      if already_persisted_servers.any?
-        out.puts "\nAlready persisted servers:"
-        already_persisted_servers.each { |info| out.puts JSON.pretty_generate(info) }
-      end
-
-      if stale_servers.any?
-        out.puts "\nStale servers:"
-        stale_servers.each { |server| out.puts JSON.pretty_generate(server.to_hash) }
-      else
-        out.puts "\nThere are no stale servers."
-      end
-      out.flush
     end
   end
 end
\ No newline at end of file
diff --git a/devops-service/spec/executors/stack_executor_spec.rb b/devops-service/spec/executors/stack_executor_spec.rb
index 52a5f81..c2652f0 100644
--- a/devops-service/spec/executors/stack_executor_spec.rb
+++ b/devops-service/spec/executors/stack_executor_spec.rb
@@ -8,26 +8,26 @@ class Devops::Executor::StackExecutor
     let(:executor_with_stack) { described_class.new(out: out, stack: stack) }
     let(:new_servers_by_priorities) {
       {
-        0 => [{id: 1}],
-        2 => [{id: 2}]
-      }
-    }
-    let(:just_persisted_by_priority) {
-      {
-        0 => [double('info 1', id: 1)],
-        2 => [double('info 2', id: 2)]
+        0 => [{'id' => 1}],
+        2 => [{'id' => 2}]
       }
     }
     let(:fetcher) {
       instance_double(StackServersFetcher,
+        servers_to_persist: new_servers_by_priorities.values.flatten,
         new_servers_by_priorities: new_servers_by_priorities,
         stale_servers: build_list(:server, 2),
-        fetch: nil
+        fetch: nil,
+        reset_states: nil
       )
     }
 
+    let(:persister) { instance_double(StackServersPersister) }
+
     before do
       allow(executor_with_stack).to receive(:fetcher) { fetcher }
+      allow(persister).to receive(:persist) { |info| build(:server, id: info['id']) }
+      allow(executor_with_stack).to receive(:persister) { persister }
     end
 
 
@@ -72,12 +72,7 @@ class Devops::Executor::StackExecutor
     end
 
     describe '#persist_new_servers' do
-      let(:persister) { instance_double(StackServersPersister, persist: build(:server)) }
-
       before do
-        allow(executor_with_stack).to receive(:persister) { persister }
-        allow(stack).to receive(:lock_persisting!)
-        allow(stack).to receive(:unlock_persisting!)
         allow(stubbed_connector).to receive(:stack) { stack }
       end
 
@@ -85,28 +80,13 @@ class Devops::Executor::StackExecutor
         expect(persister).to receive(:persist).exactly(2).times
         executor_with_stack.persist_new_servers
       end
-
-      it 'locks persisting of a stack before start and unlocks after finish' do
-        expect(stack).to receive(:lock_persisting!).ordered
-        expect(persister).to receive(:persist).ordered
-        expect(stack).to receive(:unlock_persisting!).ordered
-        executor_with_stack.persist_new_servers
-      end
-
-      it 'unlocks persisting even in case of failures' do
-        allow(persister).to receive(:persist) { raise }
-        expect(stack).to receive(:unlock_persisting!)
-        expect { executor_with_stack.persist_new_servers }.to raise_error StandardError
-      end
     end
 
     describe '#bootstrap_just_persisted' do
       it 'calls PrioritizedGroupsBootstrapper#bootstrap_servers_by_priority' do
-        result = double('bootstrap_result')
-        allow(executor_with_stack).to receive(:just_persisted_by_priority) { just_persisted_by_priority }
-        allow_any_instance_of(PrioritizedGroupsBootstrapper).to receive(:bootstrap_servers_by_priority) { result }
         expect_any_instance_of(PrioritizedGroupsBootstrapper).to receive(:bootstrap_servers_by_priority)
-        expect(executor_with_stack.bootstrap_just_persisted(1000)).to eq result
+        executor_with_stack.persist_new_servers
+        executor_with_stack.bootstrap_just_persisted(1000)
       end
     end
 
diff --git a/devops-service/spec/workers/stack_sync_worker_spec.rb b/devops-service/spec/workers/stack_sync_worker_spec.rb
new file mode 100644
index 0000000..842c8e4
--- /dev/null
+++ b/devops-service/spec/workers/stack_sync_worker_spec.rb
@@ -0,0 +1,57 @@
+require 'workers/stack_sync_worker'
+require 'lib/executors/stack_executor'
+
+RSpec.describe StackSyncWorker, type: :worker, stubbed_connector: true, init_messages: true do
+  let(:worker) { described_class.new }
+  let(:stack) { build(:stack) }
+  let(:perform) { worker.perform('stack_name' => 'stack') }
+  let(:executor) {
+    instance_double(Devops::Executor::StackExecutor,
+      delete_stale_servers: nil,
+      persist_new_servers: nil,
+      bootstrap_just_persisted: double('result', reason: 'ok', code: 0)
+    )
+  }
+
+  before do
+    allow(worker).to receive(:update_report)
+    allow(worker).to receive(:executor) { executor }
+    allow(worker).to receive(:sleep)
+    allow(stubbed_connector).to receive(:stack) { stack }
+    allow(stubbed_connector).to receive(:lock_persisting_stack)
+    allow(stubbed_connector).to receive(:unlock_persisting_stack)
+  end
+
+  it 'saves report with owner set to SYSTEM' do
+    expect(worker).to receive(:update_report) do |options|
+      expect(options).to include('created_by' => 'SYSTEM')
+    end
+    perform
+  end
+
+  it 'locks persisting of a stack before start and unlocks after finish' do
+    expect(worker).to receive(:wait_until_stack_is_unlocked).ordered
+    expect(stack).to receive(:lock_persisting!).ordered
+    expect(executor).to receive(:delete_stale_servers).ordered
+    expect(executor).to receive(:persist_new_servers).ordered
+    expect(stack).to receive(:unlock_persisting!).ordered
+    perform
+  end
+
+  it 'unlocks persisting even in case of failures' do
+    allow(executor).to receive(:persist_new_servers) { raise }
+    expect(stack).to receive(:unlock_persisting!)
+    expect { perform }.to raise_error StandardError
+  end
+
+  it 'waites until stack is unlocked' do
+    allow(stubbed_connector).to receive(:stack).and_return(
+      build(:stack, persisting_is_locked: true),
+      build(:stack, persisting_is_locked: true),
+      build(:stack, persisting_is_locked: false)
+    )
+    expect(worker).to receive(:sleep).exactly(2).times
+    perform
+  end
+
+end
\ No newline at end of file
diff --git a/devops-service/workers/stack_bootstrap_worker.rb b/devops-service/workers/stack_bootstrap_worker.rb
index 9bddac9..af263a0 100644
--- a/devops-service/workers/stack_bootstrap_worker.rb
+++ b/devops-service/workers/stack_bootstrap_worker.rb
@@ -60,12 +60,8 @@ class StackBootstrapWorker < Worker
 
   def rollback_stack!
     puts_and_flush "\nStart rollback of a stack"
-    begin
-      executor.delete_stack
-      puts_and_flush "Stack rollback has been completed"
-    rescue StandardError
-      puts_and_flush "Stack rollback failed"
-    end
+    executor.delete_stack
+    puts_and_flush "Stack rollback has been completed"
   end
 
   def save_report(stack_attrs)
diff --git a/devops-service/workers/stack_sync_worker.rb b/devops-service/workers/stack_sync_worker.rb
index 76e44cb..9aa7aa4 100644
--- a/devops-service/workers/stack_sync_worker.rb
+++ b/devops-service/workers/stack_sync_worker.rb
@@ -2,7 +2,7 @@ require 'lib/executors/stack_executor'
 
 class StackSyncWorker < Worker
 
-  MAX_LOCK_WAITING_TIME = 15000
+  MAX_LOCK_WAITING_TIME = 6000
 
   # @options:
   #   'stack_name'    required
@@ -12,14 +12,16 @@ class StackSyncWorker < Worker
       stack_name = options.fetch('stack_name')
       created_by = options['created_by'] || ::Devops::Model::Report::SYSTEM_OWNER
       @stack = mongo.stack(stack_name)
-
       save_report(created_by)
-      wait_until_stack_is_unlocked
-      puts_and_flush 'Persisting new servers.'
-      executor.persist_new_servers
 
-      puts_and_flush "\n\nDeleting stale servers."
-      executor.delete_stale_servers
+      wait_until_stack_is_unlocked
+      begin
+        @stack.lock_persisting!
+        executor.delete_stale_servers
+        executor.persist_new_servers
+      ensure
+        @stack.unlock_persisting!
+      end
 
       puts_and_flush "\n\nBootstrapping just persisted servers."
       bootstrap_result = executor.bootstrap_just_persisted(jid)