diff --git a/install/class.Setup.php b/install/class.Setup.php
index 514a156965..ff83c58920 100644
--- a/install/class.Setup.php
+++ b/install/class.Setup.php
@@ -26,6 +26,7 @@
 use oat\oatbox\log\LoggerService;
 use oat\oatbox\service\ConfigurableService;
 use oat\oatbox\service\ServiceManager;
+use oat\tao\model\install\seed\SeedSorter;
 use Zend\ServiceManager\ServiceLocatorAwareInterface;
 
 class tao_install_Setup implements Action
@@ -52,6 +53,7 @@ class tao_install_Setup implements Action
      * @throws common_ext_ExtensionException When a presented parameter is invalid or malformed.
      * @throws InvalidArgumentException
      * @throws tao_install_utils_Exception
+     * @throws ReflectionException
      */
     public function __invoke($params)
     {
@@ -223,12 +225,10 @@ public function __invoke($params)
         } elseif (!isset($persistences['type'])) {
             throw new InvalidArgumentException('Your config should have a \'default\' key under \'persistences\'');
         }
-
+        $seedSorter = new SeedSorter();
         foreach ($parameters['configuration'] as $extension => $configs) {
 
-            $sortedConfigs = $this->sortConfigs($serviceManager, $configs);
-
-            var_dump(array_keys($sortedConfigs));
+            $configs = $seedSorter->sort($configs);
 
             foreach ($configs as $key => $config) {
                 if (isset($config['type']) && $config['type'] === 'configurableService') {
@@ -292,64 +292,6 @@ public function __invoke($params)
         $this->logNotice('Installation completed!');
     }
 
-    private function getDependencies(string $className): array
-    {
-        $reflection = new ReflectionClass($className);
-
-        $constructor = $reflection->getConstructor();
-
-        $result = [];
-
-        foreach ($constructor->getParameters() as $parameter) {
-            if ($class = $parameter->getClass()) {
-                $result[] = $class->name;
-            }
-        }
-
-        return $result;
-    }
-
-    private function sortDependencies(ServiceManager $serviceManager, array $graph, string $key, array &$result): void
-    {
-        echo "> $key\n";
-        echo ">> {$graph[$key]['class']}\n";
-
-//        if (!isset($graph[$key]) || !$serviceManager->get($graph[$key]['class'])) {
-//            throw new Exception("No '$key' in graph");
-//        }
-
-        if (isset($result[$key])) {
-            return;
-        }
-
-        if (!isset($graph[$key]['class'])) {
-            return;
-        }
-
-        $className = $graph[$key]['class'];
-
-        $deps = $this->getDependencies($className);
-
-        var_dump($deps);
-
-        foreach ($deps as $depKey) {
-            $this->sortDependencies($serviceManager, $graph, $depKey, $result);
-        }
-
-        $result[$key] = $graph[$key];
-    }
-
-    private function sortConfigs(ServiceManager $serviceManager, array $config): array
-    {
-        $result = [];
-
-        foreach ($config as $key => $value) {
-            $this->sortDependencies($serviceManager, $config, $key, $result);
-        }
-
-        return $result;
-    }
-
     /**
      * @param string         $class
      * @param array          $parametersToSort
diff --git a/models/classes/install/seed/SeedSorter.php b/models/classes/install/seed/SeedSorter.php
new file mode 100644
index 0000000000..e089f1403f
--- /dev/null
+++ b/models/classes/install/seed/SeedSorter.php
@@ -0,0 +1,120 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2020 (original work) Open Assessment Technologies SA;
+ *
+ */
+
+declare(strict_types=1);
+
+namespace oat\tao\model\install\seed;
+
+use ReflectionClass;
+use ReflectionException;
+
+class SeedSorter
+{
+    /**
+     * @throws ReflectionException
+     */
+    public function sort(array $config): array
+    {
+        $sortedConfig = [];
+
+        foreach ($config as $serviceKey => $serviceConfig) {
+            $this->sortDependencies($config, $serviceKey, $sortedConfig);
+        }
+
+        return $sortedConfig;
+    }
+
+    /**
+     * @throws ReflectionException
+     */
+    private function getDependencies(string $className): array
+    {
+        $reflection = new ReflectionClass($className);
+
+        $constructor = $reflection->getConstructor();
+
+        if (null === $constructor) {
+            return [];
+        }
+
+        $dependencies = [];
+
+        foreach ($constructor->getParameters() as $parameter) {
+            if ($class = $parameter->getClass()) {
+                $dependencies[] = $class->name;
+            }
+        }
+
+        return $dependencies;
+    }
+
+    /**
+     * @throws ReflectionException
+     */
+    private function sortDependencies(array $config, string $serviceKey, array &$result): void
+    {
+        if (isset($result[$serviceKey])) {
+            return;
+        }
+
+        if (!isset($config[$serviceKey]['class'])) {
+            $result[$serviceKey] = $config[$serviceKey];
+
+            return;
+        }
+
+        $serviceClassName = $config[$serviceKey]['class'];
+
+        $dependencies = $this->getDependencies($serviceClassName);
+
+        foreach ($dependencies as $dependencyClassName) {
+            try {
+                $dependencyKey = $this->findServiceKey($config, $dependencyClassName);
+                $this->sortDependencies($config, $dependencyKey, $result);
+            } catch (SeedSorterException $e) {
+                continue;
+            }
+        }
+
+        $result[$serviceKey] = $config[$serviceKey];
+    }
+
+    private function findServiceKey(array $config, string $className)
+    {
+        foreach ($config as $serviceKey => $serviceConfig) {
+            if (empty($serviceConfig['class'])) {
+                throw new SeedSorterException(
+                    sprintf('%s not a class', $className)
+                );
+            }
+
+            if (
+                $serviceConfig['class'] === $className
+                || is_subclass_of($serviceConfig['class'], $className)
+            ) {
+                return $serviceKey;
+            }
+        }
+
+        throw new SeedSorterException(
+            sprintf('Service key for class %s not found', $className)
+        );
+    }
+}
diff --git a/models/classes/install/seed/SeedSorterException.php b/models/classes/install/seed/SeedSorterException.php
new file mode 100644
index 0000000000..347454fbf8
--- /dev/null
+++ b/models/classes/install/seed/SeedSorterException.php
@@ -0,0 +1,29 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2020 (original work) Open Assessment Technologies SA;
+ *
+ */
+
+declare(strict_types=1);
+
+namespace oat\tao\model\install\seed;
+
+use RuntimeException;
+
+class SeedSorterException extends RuntimeException
+{
+}
diff --git a/test/unit/install/seed/SeedSorterTest.php b/test/unit/install/seed/SeedSorterTest.php
new file mode 100644
index 0000000000..a3a0a35e6f
--- /dev/null
+++ b/test/unit/install/seed/SeedSorterTest.php
@@ -0,0 +1,174 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2020 (original work) Open Assessment Technologies SA;
+ *
+ */
+
+declare(strict_types=1);
+
+namespace oat\tao\test\unit\models\install\seed;
+
+use oat\generis\test\TestCase;
+use oat\tao\model\install\seed\SeedSorter;
+use ReflectionException;
+
+interface NoDepInterface {
+
+}
+
+class NoDepClass implements NoDepInterface
+{
+}
+
+class NoDepNotInConfigClass
+{
+}
+
+class DepFromServiceInConfigClass
+{
+    public function __construct(NoDepClass $class)
+    {
+    }
+}
+
+class DepFromInterfaceInConfigClass
+{
+    public function __construct(NoDepInterface $class)
+    {
+    }
+}
+
+class Dep2FromServiceInConfigClass
+{
+    public function __construct(DepFromServiceInConfigClass $class)
+    {
+    }
+}
+
+class DoubleDepFromServiceInConfigClass
+{
+    public function __construct(DepFromServiceInConfigClass $class, NoDepClass $class2)
+    {
+    }
+}
+
+class DoubleDepFromServiceInConfigAndNotInConfigClass
+{
+    public function __construct(NoDepNotInConfigClass $class, DoubleDepFromServiceInConfigClass $class2)
+    {
+    }
+}
+
+class DepFromServiceNotInConfigClass
+{
+    public function __construct(NoDepNotInConfigClass $class)
+    {
+    }
+}
+
+class NoDepArrayClass
+{
+    public function __construct(array $array)
+    {
+    }
+}
+
+class SeedSorterTest extends TestCase
+{
+    /** @var SeedSorter */
+    private $sorter;
+
+    protected function setUp(): void
+    {
+        $this->sorter = new SeedSorter();
+    }
+
+    /**
+     * @throws ReflectionException
+     */
+    public function testSortConfigs(): void
+    {
+        $configConfiguration = [
+            'DepFromInterfaceInConfigClass' => [
+                'class' => DepFromInterfaceInConfigClass::class,
+            ],
+            'DoubleDepFromServiceInConfigAndNotInConfigClass' => [
+                'class' => DoubleDepFromServiceInConfigAndNotInConfigClass::class,
+            ],
+            'DepFromServiceNotInConfigClass'                  => [
+                'class' => DepFromServiceNotInConfigClass::class,
+            ],
+            'Dep2FromServiceInConfigClass'                    => [
+                'class' => Dep2FromServiceInConfigClass::class,
+            ],
+            'DoubleDepFromServiceInConfigClass'               => [
+                'class' => DoubleDepFromServiceInConfigClass::class,
+            ],
+            'DepFromServiceInConfigClass'                     => [
+                'class' => DepFromServiceInConfigClass::class,
+            ],
+            'NoDepArrayClass'                                 => [
+                'class' => NoDepArrayClass::class,
+            ],
+            'NoDepClass'                                      => [
+                'class' => NoDepClass::class,
+            ],
+            'NotAClass'                                       => [
+                'some' => 'config',
+            ],
+        ];
+
+        $sortedConfigs = $this->sorter->sort($configConfiguration);
+
+        $this->assertKeysAfter(['NoDepClass'], 'DepFromServiceInConfigClass', $sortedConfigs);
+        $this->assertKeysAfter(['NoDepClass'], 'DepFromInterfaceInConfigClass', $sortedConfigs);
+        $this->assertKeysAfter(
+            ['DoubleDepFromServiceInConfigClass'],
+            'DoubleDepFromServiceInConfigAndNotInConfigClass',
+            $sortedConfigs
+        );
+        $this->assertKeysAfter(
+            ['NoDepClass', 'DepFromServiceInConfigClass'],
+            'DoubleDepFromServiceInConfigClass',
+            $sortedConfigs
+        );
+
+        self::assertArrayHasKey('NoDepClass', $sortedConfigs);
+        self::assertArrayHasKey('NoDepArrayClass', $sortedConfigs);
+        self::assertArrayHasKey('DepFromServiceNotInConfigClass', $sortedConfigs);
+        self::assertArrayHasKey('NotAClass', $sortedConfigs);
+    }
+
+    private function assertKeysAfter(array $priorKeys, string $needleKey, array $array): void
+    {
+        $maxKeyIndex = 0;
+
+        $arrayKeys = array_keys($array);
+
+        foreach ($priorKeys as $priorKey) {
+            $keyIndex = array_search($priorKey, $arrayKeys, true);
+
+            self::assertIsInt($keyIndex);
+
+            if ($maxKeyIndex < $keyIndex) {
+                $maxKeyIndex = $keyIndex;
+            }
+        }
+
+        self::assertTrue($maxKeyIndex < array_search($needleKey, $arrayKeys, true));
+    }
+}