app\config.yml

# winzouBookBundle
winzou_book:
    entry:
        entity:
            class: Asso\BookBundle\Entity\Entry
        manager:
            class: Asso\BookBundle\Entity\Manager\EntryManager

Bundle\Resources\config\services.yml

services:
    winzou_book.entry_manager:
        class:     %winzou_book.entry.manager.class%
        arguments: [@doctrine.orm.entity_manager, %winzou_book.entry.entity.class%]

DependencyInjection\Configuration.php

<?php

namespace winzou\BookBundle\DependencyInjection;

use Symfony\Component\Config\Definition\Builder\TreeBuilder;

class Configuration
{
    public function getConfigTree()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root('winzou_book');
        
        $rootNode
            ->children()
                ->arrayNode('entry')
                    ->children()
                        ->arrayNode('entity')
                            ->children()
                                ->scalarNode('class')->isRequired()->cannotBeEmpty()->end()
                            ->end()
                        ->end()
                        ->arrayNode('manager')
                            ->children()
                                ->scalarNode('class')->defaultValue('winzou\\BookBundle\\Entity\\Manager\\EntryManager')->end()
                            ->end()
                        ->end()
                     ->end()
                 ->end()
                 ->arrayNode('account')
                    ->children()
                        ->arrayNode('entity')
                            ->children()
                                ->scalarNode('class')->defaultValue('winzou\\BookBundle\\Entity\\Account')->end()
                            ->end()
                        ->end()
                        ->arrayNode('manager')
                            ->children()
                                ->scalarNode('class')->defaultValue('winzou\\BookBundle\\Entity\\Manager\\AccountManager')->end()
                            ->end()
                        ->end()
                     ->end()
                ->end()
            ->end();
            
        return $treeBuilder->buildTree();
    }
}

DependencyInjection\winzouBookExtension.php

<?php

namespace winzou\BookBundle\DependencyInjection;

use Symfony\Component\Config\Definition\Processor;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;
use Symfony\Component\HttpKernel\DependencyInjection\Extension;
use Symfony\Component\Config\FileLocator;

class winzouBookExtension extends Extension
{
    public function load(array $configs, ContainerBuilder $container)
    {
        $processor     = new Processor();
        $configuration = new Configuration();

        $config = $processor->process($configuration->getConfigTree(), $configs);
        var_dump($config);
            
        $loader = new YamlFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
        $loader->load('services.yml');
    }
}