diff --git a/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
index ee43451..81f528f 100644
--- a/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
+++ b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
@@ -2,13 +2,16 @@
 
 namespace Drupal\migrate\Plugin\migrate\source;
 
+use Drupal\Core\Database\ConnectionNotDefinedException;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\State\StateInterface;
+use Drupal\migrate\Exception\RequirementsException;
 use Drupal\migrate\MigrateException;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Plugin\migrate\id_map\Sql;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
+use Drupal\migrate\Plugin\RequirementsInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -20,7 +23,7 @@
  * is present, it is used as a database connection information array to define
  * the connection.
  */
-abstract class SqlBase extends SourcePluginBase implements ContainerFactoryPluginInterface {
+abstract class SqlBase extends SourcePluginBase implements ContainerFactoryPluginInterface, RequirementsInterface {
 
   /**
    * The query string.
@@ -127,12 +130,17 @@ public function getDatabase() {
    *
    * @return \Drupal\Core\Database\Connection
    *   The connection to use for this plugin's queries.
+   *
+   * @throws \Drupal\migrate\Exception\RequirementsException
+   *   Thrown if there is no properly-configured database.
    */
   protected function setUpDatabase(array $database_info) {
     if (isset($database_info['key'])) {
       $key = $database_info['key'];
     }
     else {
+      // If there is no explicit database configuration at all, fallback to a
+      // connection named 'migrate'.
       $key = 'migrate';
     }
     if (isset($database_info['target'])) {
@@ -144,7 +152,29 @@ protected function setUpDatabase(array $database_info) {
     if (isset($database_info['database'])) {
       Database::addConnectionInfo($key, $target, $database_info['database']);
     }
-    return Database::getConnection($target, $key);
+    try {
+      $connection = Database::getConnection($target, $key);
+    }
+    catch (ConnectionNotDefinedException $e) {
+      // If we fell back to the magic 'migrate' connection and it doesn't exist,
+      // treat the lack of the connection as a RequirementsException.
+      if ($key == 'migrate') {
+        throw new RequirementsException("No database connection configured for source plugin " . $this->pluginId);
+      }
+      else {
+        throw $e;
+      }
+    }
+    return $connection;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function checkRequirements() {
+    if ($this->pluginDefinition['requirements_met'] === TRUE) {
+      $this->getDatabase();
+    }
   }
 
   /**
diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/source/DrupalSqlBase.php b/core/modules/migrate_drupal/src/Plugin/migrate/source/DrupalSqlBase.php
index 3af971c..3c3624d 100644
--- a/core/modules/migrate_drupal/src/Plugin/migrate/source/DrupalSqlBase.php
+++ b/core/modules/migrate_drupal/src/Plugin/migrate/source/DrupalSqlBase.php
@@ -10,7 +10,6 @@
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Exception\RequirementsException;
 use Drupal\migrate\Plugin\migrate\source\SqlBase;
-use Drupal\migrate\Plugin\RequirementsInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -19,7 +18,7 @@
  * Mainly to let children retrieve information from the origin system in an
  * easier way.
  */
-abstract class DrupalSqlBase extends SqlBase implements ContainerFactoryPluginInterface, RequirementsInterface, DependentPluginInterface {
+abstract class DrupalSqlBase extends SqlBase implements ContainerFactoryPluginInterface, DependentPluginInterface {
 
   use DependencyTrait;
 
@@ -106,6 +105,7 @@ public function checkRequirements() {
         }
       }
     }
+    parent::checkRequirements();
   }
 
   /**
diff --git a/core/modules/node/src/Plugin/migrate/D6NodeDeriver.php b/core/modules/node/src/Plugin/migrate/D6NodeDeriver.php
index 3fba70a..9b2c3cd 100644
--- a/core/modules/node/src/Plugin/migrate/D6NodeDeriver.php
+++ b/core/modules/node/src/Plugin/migrate/D6NodeDeriver.php
@@ -90,6 +90,16 @@ public function getDerivativeDefinitions($base_plugin_definition) {
       return $this->derivatives;
     }
 
+    $node_types = static::getSourcePlugin('d6_node_type');
+    try {
+      $node_types->checkRequirements();
+    }
+    catch (RequirementsException $e) {
+      // If the d6_node_type requirements failed, that means we do not have a
+      // Drupal source database configured - there is nothing to generate.
+      return $this->derivatives;
+    }
+
     // Read all CCK field instance definitions in the source database.
     $fields = array();
     try {
@@ -107,7 +117,7 @@ public function getDerivativeDefinitions($base_plugin_definition) {
     }
 
     try {
-      foreach (static::getSourcePlugin('d6_node_type') as $row) {
+      foreach ($node_types as $row) {
         $node_type = $row->getSourceProperty('type');
         $values = $base_plugin_definition;
 
diff --git a/core/modules/node/src/Plugin/migrate/D7NodeDeriver.php b/core/modules/node/src/Plugin/migrate/D7NodeDeriver.php
index bd3d8b9..3fc2682 100644
--- a/core/modules/node/src/Plugin/migrate/D7NodeDeriver.php
+++ b/core/modules/node/src/Plugin/migrate/D7NodeDeriver.php
@@ -65,6 +65,16 @@ public static function create(ContainerInterface $container, $base_plugin_id) {
    * {@inheritdoc}
    */
   public function getDerivativeDefinitions($base_plugin_definition) {
+    $node_types = static::getSourcePlugin('d7_node_type');
+    try {
+      $node_types->checkRequirements();
+    }
+    catch (RequirementsException $e) {
+      // If the d7_node_type requirements failed, that means we do not have a
+      // Drupal source database configured - there is nothing to generate.
+      return $this->derivatives;
+    }
+
     $fields = [];
     try {
       $source_plugin = static::getSourcePlugin('d7_field_instance');
@@ -84,7 +94,7 @@ public function getDerivativeDefinitions($base_plugin_definition) {
     }
 
     try {
-      foreach (static::getSourcePlugin('d7_node_type') as $row) {
+      foreach ($node_types as $row) {
         $node_type = $row->getSourceProperty('type');
         $values = $base_plugin_definition;
 
diff --git a/core/modules/node/tests/src/Kernel/Migrate/MigratePluginListTest.php b/core/modules/node/tests/src/Kernel/Migrate/MigratePluginListTest.php
new file mode 100644
index 0000000..e220717
--- /dev/null
+++ b/core/modules/node/tests/src/Kernel/Migrate/MigratePluginListTest.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Drupal\Tests\node\Kernel\Migrate;
+
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\migrate\Exception\RequirementsException;
+use Drupal\migrate\Plugin\migrate\source\SqlBase;
+use Drupal\migrate\Plugin\RequirementsInterface;
+
+/**
+ * Tests the migration plugin manager with node derivers.
+ *
+ * @coversDefaultClass \Drupal\migrate\Plugin\MigratePluginManager
+ * @group node
+ */
+class MigratePluginListTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = [
+    // Include modules defining required migrations for the node migrations.
+    'migrate',
+    'migrate_drupal',
+    'field',
+    'filter',
+    'node',
+    'user',
+  ];
+
+  /**
+   * @covers ::getDefinitions
+   */
+  public function testGetDefinitions() {
+    // Make sure retrieving these migration plugins in the absence of a database
+    // connection does not throw any errors.
+    $migration_plugins = $this->container->get('plugin.manager.migration')->createInstances([]);
+    // Any database-based source plugins should fail a requirements test in the
+    // absence of a database connection.
+    /** @var \Drupal\migrate\Plugin\Migration $migration */
+    foreach ($migration_plugins as $id => $migration) {
+      if ($migration->getSourcePlugin() instanceof RequirementsInterface) {
+        try {
+          $migration->getSourcePlugin()->checkRequirements();
+        }
+        catch (RequirementsException $e) {
+          unset($migration_plugins[$id]);
+        }
+      }
+    }
+
+    // Without a connection defined, no database-based plugins should be
+    // returned.
+    foreach ($migration_plugins as $id => $migration) {
+      $this->assertNotInstanceOf(SqlBase::class, $migration->getSourcePlugin());
+    }
+  }
+
+}