diff --git a/app/assets/javascripts/alert.js b/app/assets/javascripts/alert.js
index f400adb..53b21d7 100644
--- a/app/assets/javascripts/alert.js
+++ b/app/assets/javascripts/alert.js
@@ -1,6 +1,7 @@
 (function(){
   "use strict";
-  var POLLING_INTERVAL = 1 * 1000;
+  var POLLING_INTERVAL = 3 * 1000;
+  var POLLING_URL = "/polling/alerts";
 
   $(function(){
     var alert = new Vue({
@@ -11,33 +12,30 @@
 
       created: function(){
         var self = this;
-        setInterval(function(){
-          self.fetchData().then(function(alerts){
+        var fetch = function(){
+          self.fetchAlertsData().then(function(alerts){
             self.alerts = alerts;
           });
-        }, POLLING_INTERVAL);
+        };
+        fetch();
+        setInterval(fetch, POLLING_INTERVAL);
       },
 
       computed: {
+        alertsCount: {
+          $get: function(){ return this.alerts.length; }
+        },
         hasAlerts: {
-          $get: function(){
-            return this.alerts.length > 0;
-          }
+          $get: function(){ return this.alertsCount > 0; }
         }
       },
 
       methods: {
-        fetchData: function() {
-          // TODO: fetch from Rails app
+        fetchAlertsData: function() {
           return new Promise(function(resolve, reject) {
-            resolve([
-              {
-                "text": "dummy: " + (new Date).toString(),
-              },
-              {
-                "text": "dummy: " + (Math.random()).toString(),
-              },
-            ]);
+            $.getJSON(POLLING_URL, function(data){
+              resolve(data);
+            }).fail(reject);
           });
         }
       }
diff --git a/app/assets/stylesheets/common.css.scss b/app/assets/stylesheets/common.css.scss
index b1c4800..2e3b8b5 100644
--- a/app/assets/stylesheets/common.css.scss
+++ b/app/assets/stylesheets/common.css.scss
@@ -27,3 +27,13 @@ label {
 #page-wrapper {
   padding-bottom: 2em;
 }
+
+
+// expand alert area width
+.navbar-top-links .dropdown-messages,
+.navbar-top-links .dropdown-tasks,
+.navbar-top-links .dropdown-alerts {
+    // width: 310px;
+    width: 400px;
+    min-width: 0;
+}
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 3d74a6f..d505276 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -4,6 +4,7 @@ class ApplicationController < ActionController::Base
   protect_from_forgery with: :exception
   helper_method :current_user
   helper_method :current_locale
+  helper_method :installing_gem?, :installing_gems, :uninstalling_gem?, :uninstalling_gems
   before_action :login_required
   before_action :set_locale
 
@@ -21,6 +22,26 @@ class ApplicationController < ActionController::Base
     I18n.locale
   end
 
+  def installing_gem?
+    installing_gems.length > 0
+  end
+
+  def installing_gems
+    Plugin::WORKING.find_all do |data|
+      data[:type] == :install && data[:state] == :running
+    end.map{|data| data[:plugin]} || []
+  end
+
+  def uninstalling_gem?
+    uninstalling_gems.length > 0
+  end
+
+  def uninstalling_gems
+    Plugin::WORKING.find_all do |data|
+      data[:type] == :uninstall && data[:state] == :running
+    end.map{|data| data[:plugin]} || []
+  end
+
   private
 
   def find_fluentd
diff --git a/app/controllers/polling_controller.rb b/app/controllers/polling_controller.rb
new file mode 100644
index 0000000..cb70e98
--- /dev/null
+++ b/app/controllers/polling_controller.rb
@@ -0,0 +1,20 @@
+class PollingController < ApplicationController
+  def alerts
+    alerts = []
+    installing_gems.each do |plugin|
+      target = plugin.gem_name.dup
+      target << "(#{plugin.version})" if plugin.version
+      alerts << {
+        text: I18n.t('terms.installing', target: target)
+      }
+    end
+    uninstalling_gems.each do |plugin|
+      target = plugin.gem_name.dup
+      target << "(#{plugin.version})" if plugin.version
+      alerts << {
+        text: I18n.t('terms.uninstalling', target: target)
+      }
+    end
+    render json: alerts
+  end
+end
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 9332f5b..9ab688d 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -5,26 +5,6 @@ module ApplicationHelper
     Plugin.gemfile_changed?
   end
 
-  def installing_gem?
-    installing_gems.length > 0
-  end
-
-  def installing_gems
-    Plugin::WORKING.find_all do |data|
-      data[:type] == :install && data[:state] == :running
-    end.map{|data| data[:plugin]} || []
-  end
-
-  def uninstalling_gem?
-    uninstalling_gems.length > 0
-  end
-
-  def uninstalling_gems
-    Plugin::WORKING.find_all do |data|
-      data[:type] == :uninstall && data[:state] == :running
-    end.map{|data| data[:plugin]} || []
-  end
-
   def has_td_agent_system?
     File.exist?("/etc/init.d/td-agent")
   end
diff --git a/config/locales/translation_en.yml b/config/locales/translation_en.yml
index 16dd54a..56ad605 100644
--- a/config/locales/translation_en.yml
+++ b/config/locales/translation_en.yml
@@ -24,6 +24,8 @@ en:
     new: New
     setup: "Setup %{target}"
     install_it: "Install %{target}"
+    installing: "Installing: %{target}"
+    uninstalling: "Uninstalling: %{target}"
 
   plugins:
     common: &plugin_common
diff --git a/config/locales/translation_ja.yml b/config/locales/translation_ja.yml
index 8350c3a..8dbf6da 100644
--- a/config/locales/translation_ja.yml
+++ b/config/locales/translation_ja.yml
@@ -24,6 +24,8 @@ ja:
     new: 新規作成
     setup: "%{target}をセットアップ"
     install_it: "%{target}をインストール"
+    installing: "インストール中: %{target}"
+    uninstalling: "アンインストール中: %{target}"
 
   plugins:
     common: &plugin_common
diff --git a/config/routes.rb b/config/routes.rb
index bc2d9ac..ed64061 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -25,7 +25,12 @@ Rails.application.routes.draw do
     end
   end
 
+  resource :user, only: [:show, :edit, :update]
+
   get "misc" => "misc#show"
   get "misc/information"
-  resource :user, only: [:show, :edit, :update]
+
+  namespace :polling do
+    get "alerts"
+  end
 end
diff --git a/spec/controllers/polling_controller_spec.rb b/spec/controllers/polling_controller_spec.rb
new file mode 100644
index 0000000..f76a2de
--- /dev/null
+++ b/spec/controllers/polling_controller_spec.rb
@@ -0,0 +1,5 @@
+require 'spec_helper'
+
+describe PollingController do
+
+end