diff --git a/core/tests/Drupal/KernelTests/KernelTestBase.php b/core/tests/Drupal/KernelTests/KernelTestBase.php
index ed5cda0ae9..672c3fe99e 100644
--- a/core/tests/Drupal/KernelTests/KernelTestBase.php
+++ b/core/tests/Drupal/KernelTests/KernelTestBase.php
@@ -179,6 +179,13 @@
    */
   protected $configImporter;
 
+  /**
+   * The key_value service that must persist between container rebuilds.
+   *
+   * @var \Drupal\Core\KeyValueStore\KeyValueMemoryFactory
+   */
+  protected $keyValue;
+
   /**
    * The app root.
    *
@@ -534,6 +541,14 @@ public function register(ContainerBuilder $container) {
     $container
       ->setAlias('keyvalue', 'keyvalue.memory');
 
+    // Must persist container rebuilds, or all data would vanish otherwise.
+    if (isset($this->keyValue)) {
+      $container->set('keyvalue.memory', $this->keyValue);
+    }
+    else {
+      $this->keyValue = $container->get('keyvalue.memory');
+    }
+
     // Set the default language on the minimal container.
     $container->setParameter('language.default_values', Language::$defaultValues);