diff --git a/core/includes/common.inc b/core/includes/common.inc
index 5e9ff1c..69b201a 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -2938,7 +2938,7 @@ function drupal_pre_render_styles($elements) {
   // browser-caching. The string changes on every update or full cache
   // flush, forcing browsers to load a new copy of the files, as the
   // URL changed.
-  $query_string = variable_get('css_js_query_string', '0');
+  $query_string = state()->get('system.css_js_query_string') ?: '0';
 
   // For inline CSS to validate as XHTML, all CSS containing XHTML needs to be
   // wrapped in CDATA. To make that backwards compatible with HTML 4, we need to
@@ -3969,7 +3969,7 @@ function drupal_pre_render_scripts($elements) {
   // URL changed. Files that should not be cached (see drupal_add_js())
   // get REQUEST_TIME as query-string instead, to enforce reload on every
   // page request.
-  $default_query_string = variable_get('css_js_query_string', '0');
+  $default_query_string = state()->get('system.css_js_query_string') ?: '0';
 
   // For inline JavaScript to validate as XHTML, all JavaScript containing
   // XHTML needs to be wrapped in CDATA. To make that backwards compatible
@@ -6484,7 +6484,7 @@ function drupal_flush_all_caches() {
  */
 function _drupal_flush_css_js() {
   // The timestamp is converted to base 36 in order to make it more compact.
-  variable_set('css_js_query_string', base_convert(REQUEST_TIME, 10, 36));
+  state()->set('system.css_js_query_string', base_convert(REQUEST_TIME, 10, 36));
 }
 
 /**
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 803947f..d0958c0 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -367,6 +367,13 @@ function install_begin_request(&$install_state) {
       ))
       ->addMethodCall('setUserAgent', array('Drupal (+http://drupal.org/)'));
 
+    $container->register('keyvalue', 'Drupal\Core\KeyValueStore\KeyValueFactory')
+      ->addArgument(new Reference('service_container'));
+    $container->register('keyvalue.memory', 'Drupal\Core\KeyValueStore\KeyValueMemoryFactory');
+    // Override the default keyvalue storage to use memory as the database is
+    // not available.
+    $conf['keyvalue_default'] = 'keyvalue.memory';
+
     drupal_container($container);
   }
 
@@ -1087,7 +1094,7 @@ function install_database_errors($database, $settings_file) {
  * @see install_settings_form_validate()
  */
 function install_settings_form_submit($form, &$form_state) {
-  global $install_state;
+  global $install_state, $conf;
 
   // Update global settings array and save.
   $settings['databases'] = array(
@@ -1104,6 +1111,10 @@ function install_settings_form_submit($form, &$form_state) {
   // Add the config directories to settings.php.
   drupal_install_config_directories();
 
+  // The container is about to be rebuilt so we need to unset the keyvalue
+  // storage override that the installer is using.
+  unset($conf['keyvalue_default']);
+
   // Indicate that the settings file has been verified, and check the database
   // for the last completed task, now that we have a valid connection. This
   // last step is important since we want to trigger an error if the new
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/CascadingStylesheetsTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/CascadingStylesheetsTest.php
index 30cf24e..58ecc99 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/CascadingStylesheetsTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/CascadingStylesheetsTest.php
@@ -77,7 +77,7 @@ function testRenderFile() {
     $styles = drupal_get_css();
     $this->assertTrue(strpos($styles, $css) > 0, 'Rendered CSS includes the added stylesheet.');
     // Verify that newlines are properly added inside style tags.
-    $query_string = variable_get('css_js_query_string', '0');
+    $query_string = state()->get('system.css_js_query_string') ?: '0';
     $css_processed = "<style media=\"all\">\n@import url(\"" . check_plain(file_create_url($css)) . "?" . $query_string ."\");\n</style>";
     $this->assertEqual(trim($styles), $css_processed, 'Rendered CSS includes newlines inside style tags for JavaScript use.');
   }
@@ -227,7 +227,7 @@ function testAlter() {
    */
   function testAddCssFileWithQueryString() {
     $this->drupalGet('common-test/query-string');
-    $query_string = variable_get('css_js_query_string', '0');
+    $query_string = state()->get('system.css_js_query_string') ?: '0';
     $this->assertRaw(drupal_get_path('module', 'node') . '/node.admin.css?' . $query_string, 'Query string was appended correctly to css.');
     $this->assertRaw(drupal_get_path('module', 'node') . '/node-fake.css?arg1=value1&amp;arg2=value2', 'Query string not escaped on a URI.');
   }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
index 3c54ad4..b74a4e1 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
@@ -100,7 +100,7 @@ function testAddExternal() {
    * Tests adding JavaScript files with additional attributes.
    */
   function testAttributes() {
-    $default_query_string = variable_get('css_js_query_string', '0');
+    $default_query_string = state()->get('system.css_js_query_string') ?: '0';
 
     drupal_add_library('system', 'drupal');
     drupal_add_js('http://example.com/script.js', array('attributes' => array('defer' => 'defer')));
@@ -121,7 +121,7 @@ function testAggregatedAttributes() {
     // Enable aggregation.
     config('system.performance')->set('js.preprocess', 1)->save();
 
-    $default_query_string = variable_get('css_js_query_string', '0');
+    $default_query_string = state()->get('system.css_js_query_string') ?: '0';
 
     drupal_add_library('system', 'drupal');
     drupal_add_js('http://example.com/script.js', array('attributes' => array('defer' => 'defer')));
@@ -282,7 +282,7 @@ function testDifferentWeight() {
    * @see drupal_pre_render_conditional_comments()
    */
   function testBrowserConditionalComments() {
-    $default_query_string = variable_get('css_js_query_string', '0');
+    $default_query_string = state()->get('system.css_js_query_string') ?: '0';
 
     drupal_add_library('system', 'drupal');
     drupal_add_js('core/misc/collapse.js', array('browsers' => array('IE' => 'lte IE 8', '!IE' => FALSE)));
@@ -311,7 +311,7 @@ function testVersionQueryString() {
    * Tests JavaScript grouping and aggregation.
    */
   function testAggregation() {
-    $default_query_string = variable_get('css_js_query_string', '0');
+    $default_query_string = state()->get('system.css_js_query_string') ?: '0';
 
     // To optimize aggregation, items with the 'every_page' option are ordered
     // ahead of ones without. The order of JavaScript execution must be the
@@ -554,7 +554,7 @@ function testGetLibrary() {
    */
   function testAddJsFileWithQueryString() {
     $this->drupalGet('common-test/query-string');
-    $query_string = variable_get('css_js_query_string', '0');
+    $query_string = state()->get('system.css_js_query_string') ?: '0';
     $this->assertRaw(drupal_get_path('module', 'node') . '/node.js?' . $query_string, 'Query string was appended correctly to js.');
   }
 }
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index cfc9a4e..f46b45f 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1840,12 +1840,13 @@ function system_update_8031() {
 }
 
 /**
- * Removes the drupal_js_cache_files variable.
+ * Removes the drupal_js_cache_files and css_js_query_string variables.
  *
  * @ingroup config_upgrade
  */
 function system_update_8032() {
   update_variable_del('drupal_js_cache_files');
+  update_variable_del('css_js_query_string');
 }
 
 /**
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 5f540a3..1d4a29a 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -3267,9 +3267,6 @@ function system_settings_form_submit($form, &$form_state) {
  *
  * @see system_config_form_submit()
  * @ingroup forms
- *
- * @todo Replace this temporary helper with a more sophisticated solution:
- *   http://drupal.org/node/1324618.
  */
 function system_config_form($form, &$form_state) {
   $form['actions']['#type'] = 'actions';