diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 17e2a66..bcdb1b9 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -439,7 +439,7 @@ function install_run_tasks(&$install_state) {
       $install_state['tasks_performed'][] = $task_name;
       $install_state['installation_finished'] = empty($tasks_to_perform);
       if ($install_state['database_tables_exist'] && ($task['run'] == INSTALL_TASK_RUN_IF_NOT_COMPLETED || $install_state['installation_finished'])) {
-        variable_set('install_task', $install_state['installation_finished'] ? 'done' : $task_name);
+        state()->set('install_task', $install_state['installation_finished'] ? 'done' : $task_name);
       }
     }
     // Stop when there are no tasks left. In the case of an interactive
@@ -512,7 +512,7 @@ function install_run_task($task, &$install_state) {
   elseif ($task['type'] == 'batch') {
     // Start a new batch based on the task function, if one is not running
     // already.
-    $current_batch = variable_get('install_current_batch');
+    $current_batch = state()->get('install_current_batch');
     if (!$install_state['interactive'] || !$current_batch) {
       $batch = $function($install_state);
       if (empty($batch)) {
@@ -525,7 +525,7 @@ function install_run_task($task, &$install_state) {
       // task is currently running. Otherwise, we need to make sure the batch
       // will complete in one page request.
       if ($install_state['interactive']) {
-        variable_set('install_current_batch', $function);
+        state()->set('install_current_batch', $function);
       }
       else {
         $batch =& batch_get();
@@ -554,7 +554,7 @@ function install_run_task($task, &$install_state) {
       // longer requesting a batch ID.
       if ($output === FALSE) {
         // Return nothing so the next task will run in the same request.
-        variable_del('install_current_batch');
+        state()->delete('install_current_batch');
         return;
       }
       else {
@@ -921,16 +921,8 @@ function install_base_system(&$install_state) {
  *   is already installed.
  */
 function install_verify_completed_task() {
-  try {
-    if ($result = db_query("SELECT value FROM {variable} WHERE name = :name", array('name' => 'install_task'))) {
-      $task = unserialize($result->fetchField());
-    }
-  }
-  // Do not trigger an error if the database query fails, since the database
-  // might not be set up yet.
-  catch (Exception $e) {
-  }
-  if (isset($task)) {
+  $task = state()->get('install_task');
+  if ($task) {
     if ($task == 'done') {
       throw new Exception(install_already_done_error());
     }
@@ -2002,5 +1994,5 @@ function install_configure_form_submit($form, &$form_state) {
   user_login_finalize();
 
   // Record when this install ran.
-  variable_set('install_time', $_SERVER['REQUEST_TIME']);
+  state()->set('install_time', $_SERVER['REQUEST_TIME']);
 }
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 3790f2b..be03ab6 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -274,7 +274,7 @@ function system_requirements($phase) {
     // Determine when cron last ran.
     $cron_last = variable_get('cron_last');
     if (!is_numeric($cron_last)) {
-      $cron_last = variable_get('install_time', 0);
+      $cron_last = state()->get('install_time') ?: 0;
     }
 
     // Determine severity based on time since cron last ran.
@@ -1976,6 +1976,20 @@ function system_update_8021() {
 }
 
 /**
+ * Convert install_task and install_time variables to state api values.
+ */
+function system_update_8022() {
+  $variables = array('install_task', 'install_time');
+
+  foreach ($variables as $variable) {
+    if ($value = update_variable_get($variable, FALSE)) {
+      state()->set($variable, $value);
+    }
+    update_variable_del($variable);
+  }
+}
+
+/**
  * @} End of "defgroup updates-7.x-to-8.x".
  * The next series of updates should start at 9000.
  */
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index bfa91db..5e75219 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -3709,7 +3709,7 @@ function system_run_automated_cron() {
   // If the site is not fully installed, suppress the automated cron run.
   // Otherwise it could be triggered prematurely by Ajax requests during
   // installation.
-  if (($threshold = config('system.cron')->get('threshold.autorun')) > 0 && variable_get('install_task') == 'done') {
+  if (($threshold = config('system.cron')->get('threshold.autorun')) > 0 && state()->get('install_task') == 'done') {
     $cron_last = variable_get('cron_last', NULL);
     if (!isset($cron_last) || (REQUEST_TIME - $cron_last > $threshold)) {
       drupal_cron_run();