diff --git a/devops-client/lib/devops-client/options/server_options.rb b/devops-client/lib/devops-client/options/server_options.rb
index 6b844f6..0bb0f87 100644
--- a/devops-client/lib/devops-client/options/server_options.rb
+++ b/devops-client/lib/devops-client/options/server_options.rb
@@ -127,7 +127,7 @@ class ServerOptions < CommonOptions
         options[:groups] = groups.split(",")
       end
 
-      parser.recognize_option_value(:private_ip, short: '-N', i18n_scope: 'create')
+      parser.recognize_option_value(:private_ip, i18n_scope: 'create')
 
       # it was disabled somewhy
       # parser.on('--public-ip', "Associate public IP with server") do
diff --git a/devops-service/app/api2/handlers/project.rb b/devops-service/app/api2/handlers/project.rb
index 0ccd928..097737f 100644
--- a/devops-service/app/api2/handlers/project.rb
+++ b/devops-service/app/api2/handlers/project.rb
@@ -144,8 +144,10 @@ module Devops
           servers = Devops::Db.connector.servers_by_project_and_deploy_env(id, deploy_env)
           raise InvalidRecord.new("Can not delete environment '#{deploy_env}', there are #{servers.size} servers on it") unless servers.empty?
           project.delete_deploy_env(deploy_env)
+          "Deploy environment '#{deploy_env}' has been deleted from project '#{project.id}'."
         end
 
+        # updates only run_list and description
         def update_project id
           body = parser.update
           old_project = Devops::Db.connector.project id
diff --git a/devops-service/app/api2/routes/project.rb b/devops-service/app/api2/routes/project.rb
index ee1aae8..6d195fb 100644
--- a/devops-service/app/api2/routes/project.rb
+++ b/devops-service/app/api2/routes/project.rb
@@ -368,13 +368,9 @@ module Devops
           #   201 - Created
           app.post_with_headers "/project", :headers => [:accept, :content_type] do
             check_privileges("project", "w")
-            begin
-              res = Devops::API2_0::Handler::Project.new(request).create_project
-              res = "Created. " + res
-              create_response(res, nil, 201)
-            rescue InvalidRecord => e
-              halt_response(e.message)
-            end
+            res = Devops::API2_0::Handler::Project.new(request).create_project
+            res = "Created. " + res
+            create_response(res, nil, 201)
           end
 
 =begin
diff --git a/devops-service/app/api2/routes/stack.rb b/devops-service/app/api2/routes/stack.rb
index 6db26fc..ede1968 100644
--- a/devops-service/app/api2/routes/stack.rb
+++ b/devops-service/app/api2/routes/stack.rb
@@ -24,7 +24,7 @@ module Devops
           # Create stack
           #
           # * *Request*
-          #   - method : PATCH
+          #   - method : POST
           #   - headers :
           #     - Accept: application/json
           #     - Content-Type: application/json
diff --git a/devops-service/db/mongo/models/mongo_model.rb b/devops-service/db/mongo/models/mongo_model.rb
index 7525187..5351036 100644
--- a/devops-service/db/mongo/models/mongo_model.rb
+++ b/devops-service/db/mongo/models/mongo_model.rb
@@ -63,7 +63,8 @@ module Devops
           true
         rescue InvalidRecord => e
           error_message = self.build_error_message(e.message)
-          raise InvalidRecord.new(error_message)
+          # e.class may be InvalidRecord or its descendants
+          raise e.class.new(error_message)
         end
       end
 
diff --git a/devops-service/db/validators/base.rb b/devops-service/db/validators/base.rb
index 677e9f2..91b51cd 100644
--- a/devops-service/db/validators/base.rb
+++ b/devops-service/db/validators/base.rb
@@ -7,10 +7,10 @@ module Validators
     end
 
     def validate!
-      raise InvalidRecord.new(message) unless valid?
+      raise error_class.new(message) unless valid?
     rescue StandardError => e
       DevopsLogger.logger.error [e.message, e.backtrace].join("\n")
-      raise InvalidRecord.new("An error raised during validation with #{self.class}: #{e.class}: #{e.message}")
+      raise error_class.new("An error raised during validation with #{self.class}: #{e.class}: #{e.message}")
     end
 
     def valid?
@@ -21,9 +21,21 @@ module Validators
       raise 'override me'
     end
 
+    def error_class
+      self.class.get_error_class
+    end
+
     class << self
+      def get_error_class
+        @error_class || InvalidRecord
+      end
+
       private
 
+      def error_class(klass)
+        @error_class = klass
+      end
+
       # this method delegates @valid? and @message methods to helper validator, passed as block
       def delegate_to_helper_validator(&block)
 
diff --git a/devops-service/db/validators/deploy_env/deploy_envs.rb b/devops-service/db/validators/deploy_env/deploy_envs.rb
index 6ccceab..9388e46 100644
--- a/devops-service/db/validators/deploy_env/deploy_envs.rb
+++ b/devops-service/db/validators/deploy_env/deploy_envs.rb
@@ -14,6 +14,18 @@ module Validators
       true
     end
 
+    # do not rescue children validators' errors. With this:
+    #   class of child validator's error doesn't disappeared
+    #   logs doesn't contain two similar records
+    def validate!
+      raise error_class.new(message) unless valid?
+    rescue InvalidRecord => e
+      raise e
+    rescue StandardError => e
+      DevopsLogger.logger.error [e.message, e.backtrace].join("\n")
+      raise error_class.new("An error raised during validation with #{self.class}: #{e.class}: #{e.message}")
+    end
+
     def message
       "Invalid project: #{@msg}."
     end
diff --git a/devops-service/db/validators/deploy_env/users.rb b/devops-service/db/validators/deploy_env/users.rb
index ceeeebf..aadeb66 100644
--- a/devops-service/db/validators/deploy_env/users.rb
+++ b/devops-service/db/validators/deploy_env/users.rb
@@ -1,5 +1,7 @@
 module Validators
   class DeployEnv::Users < Base
+    error_class ::Devops::NonExistingUser
+
     delegate_to_helper_validator { Helpers::Users.new(@model.users) }
   end
 end
diff --git a/devops-service/db/validators/helpers/users.rb b/devops-service/db/validators/helpers/users.rb
index 430a7bc..812c36d 100644
--- a/devops-service/db/validators/helpers/users.rb
+++ b/devops-service/db/validators/helpers/users.rb
@@ -1,6 +1,9 @@
+require 'exceptions/non_existing_user'
 module Validators
   class Helpers::Users < Base
 
+    error_class ::Devops::NonExistingUser
+
     def valid?
       available_users = ::Devops::Db.connector.users_names(@model)
       @nonexistent_users = (@model || []) - available_users
diff --git a/devops-service/exceptions/devops_error.rb b/devops-service/exceptions/devops_error.rb
index fdcb6a2..a818dfd 100644
--- a/devops-service/exceptions/devops_error.rb
+++ b/devops-service/exceptions/devops_error.rb
@@ -13,7 +13,9 @@ module Devops
       end
 
       def http_body
-        JSON.pretty_generate(message: self.message)
+        error_body = {message: self.message}
+        error_body[:error_type] = error_type if respond_to?(:error_type)
+        JSON.pretty_generate(error_body)
       end
 
       def http_headers
diff --git a/devops-service/exceptions/non_existing_user.rb b/devops-service/exceptions/non_existing_user.rb
new file mode 100644
index 0000000..c71f285
--- /dev/null
+++ b/devops-service/exceptions/non_existing_user.rb
@@ -0,0 +1,8 @@
+require_relative 'invalid_record'
+module Devops
+  class NonExistingUser < ::InvalidRecord
+    def error_type
+      'unknown_user'
+    end
+  end
+end
diff --git a/devops-service/spec/models/deploy_env/deploy_env_ec2_spec.rb b/devops-service/spec/models/deploy_env/deploy_env_ec2_spec.rb
index dd3c181..2d40861 100644
--- a/devops-service/spec/models/deploy_env/deploy_env_ec2_spec.rb
+++ b/devops-service/spec/models/deploy_env/deploy_env_ec2_spec.rb
@@ -22,6 +22,13 @@ RSpec.describe Devops::Model::DeployEnvEc2, type: :model do
 
     it_behaves_like 'deploy env'
     it_behaves_like 'cloud deploy env'
+
+    it 'raises Devops::NonExistingUser when passing non existing user' do
+      env = build(:deploy_env_ec2, users: %w(wrong))
+      expect {
+        env.validate!
+      }.to raise_error Devops::NonExistingUser
+    end
   end
 
   describe '#initialize' do