diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index 6cc85d3..fca92bd 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -849,7 +849,7 @@ function drupal_installation_attempted() {
  *   the installer or during unit tests.
  *
  * @deprecated in Drupal 8.0.0, will be removed before Drupal 9.0.0.
- *   Use \Drupal::installProfile() or the install.profile container parameter
+ *   Use \Drupal::installProfile() or the install_profile container parameter
  *   instead.
  */
 function drupal_get_profile() {
diff --git a/core/lib/Drupal.php b/core/lib/Drupal.php
index 08655a8..8b15cef 100644
--- a/core/lib/Drupal.php
+++ b/core/lib/Drupal.php
@@ -187,7 +187,7 @@ public static function root() {
    *   The name of the any active install profile or distribution.
    */
   public static function installProfile() {
-    return static::getContainer()->getParameter('install.profile');
+    return static::getContainer()->getParameter('install_profile');
   }
 
   /**
diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index 3ff9d42..ce5e7d8 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -1080,7 +1080,7 @@ protected function compileContainer() {
     $container = $this->getContainerBuilder();
     $container->set('kernel', $this);
     $container->setParameter('container.modules', $this->getModulesParameter());
-    $container->setParameter('install.profile', $this->getInstallProfile());
+    $container->setParameter('install_profile', $this->getInstallProfile());
 
     // Get a list of namespaces and put it onto the container.
     $namespaces = $this->getModuleNamespacesPsr4($this->getModuleFileNames());
diff --git a/core/modules/system/src/Tests/Installer/DistributionProfileExistingSettingsTest.php b/core/modules/system/src/Tests/Installer/DistributionProfileExistingSettingsTest.php
new file mode 100644
index 0000000..f6548eb
--- /dev/null
+++ b/core/modules/system/src/Tests/Installer/DistributionProfileExistingSettingsTest.php
@@ -0,0 +1,132 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Installer\DistributionProfileExistingSettingsTest.
+ */
+
+namespace Drupal\system\Tests\Installer;
+
+use Drupal\Component\Serialization\Yaml;
+use Drupal\Core\Database\Database;
+use Drupal\Core\DrupalKernel;
+use Drupal\Core\Site\Settings;
+use Drupal\simpletest\InstallerTestBase;
+use Symfony\Component\HttpFoundation\Request;
+
+
+/**
+ * Tests distribution profile support with existing settings.
+ *
+ * @group Installer
+ */
+class DistributionProfileExistingSettingsTest extends InstallerTestBase {
+
+  /**
+   * The distribution profile info.
+   *
+   * @var array
+   */
+  protected $info;
+
+  protected function setUp() {
+    $this->info = array(
+      'type' => 'profile',
+      'core' => \Drupal::CORE_COMPATIBILITY,
+      'name' => 'Distribution profile',
+      'distribution' => array(
+        'name' => 'My Distribution',
+        'install' => array(
+          'theme' => 'bartik',
+        ),
+      ),
+    );
+    // File API functions are not available yet.
+    $path = $this->siteDirectory . '/profiles/mydistro';
+    mkdir($path, 0777, TRUE);
+    file_put_contents("$path/mydistro.info.yml", Yaml::encode($this->info));
+
+    // Pre-configure hash salt.
+    // Any string is valid, so simply use the class name of this test.
+    $this->settings['settings']['hash_salt'] = (object) array(
+      'value' => __CLASS__,
+      'required' => TRUE,
+    );
+
+    // Pre-configure database credentials.
+    $connection_info = Database::getConnectionInfo();
+    unset($connection_info['default']['pdo']);
+    unset($connection_info['default']['init_commands']);
+
+    $this->settings['databases']['default'] = (object) array(
+      'value' => $connection_info,
+      'required' => TRUE,
+    );
+
+    // Use the kernel to find the site path because the site.path service should
+    // not be available at this point in the install process.
+    $site_path = DrupalKernel::findSitePath(Request::createFromGlobals());
+    // Pre-configure config directories.
+    $this->settings['config_directories'] = array(
+      CONFIG_ACTIVE_DIRECTORY => (object) array(
+        'value' => $site_path . '/files/config_active',
+        'required' => TRUE,
+      ),
+      CONFIG_STAGING_DIRECTORY => (object) array(
+        'value' => $site_path . '/files/config_staging',
+        'required' => TRUE,
+      ),
+    );
+    mkdir($this->settings['config_directories'][CONFIG_ACTIVE_DIRECTORY]->value, 0777, TRUE);
+    mkdir($this->settings['config_directories'][CONFIG_STAGING_DIRECTORY]->value, 0777, TRUE);
+    parent::setUp();
+    $filename = $this->siteDirectory . '/settings.php';
+    // Make the settings file read-only.
+    // Not using File API; a potential error must trigger a PHP warning.
+    chmod($filename, 0444);
+  }
+
+  /**
+   * Overrides InstallerTest::setUpLanguage().
+   */
+  protected function setUpLanguage() {
+    // Verify that the distribution name appears.
+    $this->assertRaw($this->info['distribution']['name']);
+    // Verify that the requested theme is used.
+    $this->assertRaw($this->info['distribution']['install']['theme']);
+    // Verify that the "Choose profile" step does not appear.
+    $this->assertNoText('profile');
+
+    parent::setUpLanguage();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUpProfile() {
+    // This step is skipped, because there is a distribution profile.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUpSettings() {
+    // This step should not appear, since settings.php is fully configured
+    // already.
+  }
+
+  /**
+   * Confirms that the installation succeeded.
+   */
+  public function testInstalled() {
+    $this->assertUrl('user/1');
+    $this->assertResponse(200);
+    // Confirm that we are logged-in after installation.
+    $this->assertText($this->rootUser->getUsername());
+
+    // Confirm that Drupal recognizes this distribution as the current profile.
+    $this->assertEqual(\Drupal::installProfile(), 'mydistro');
+    $this->assertNull(Settings::get('install_profile'), 'The install profile has not been written to settings.php.');
+  }
+
+}
diff --git a/core/modules/system/src/Tests/Installer/DistributionProfileTest.php b/core/modules/system/src/Tests/Installer/DistributionProfileTest.php
index 55d8d59..ca43d09 100644
--- a/core/modules/system/src/Tests/Installer/DistributionProfileTest.php
+++ b/core/modules/system/src/Tests/Installer/DistributionProfileTest.php
@@ -77,6 +77,7 @@ public function testInstalled() {
 
     // Confirm that Drupal recognizes this distribution as the current profile.
     $this->assertEqual(\Drupal::installProfile(), 'mydistro');
+    $this->assertEqual(Settings::get('install_profile'), 'mydistro', 'The install profile has been written to settings.php.');
   }
 
 }