container.xml

<?xml version="1.0" encoding="utf-8"?>
<container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
    <services>
        <service id="private" class="Foo" public="false"></service>
        <service id="public" class="Foo"></service>
        <service id="service_locator" class="Symfony\Component\DependencyInjection\ServiceLocator" public="true">
            <argument type="collection">
                <argument key="private" type="service" id="private"/>
            </argument>
        </service>
        <service id="service_locator_with_alias_key" class="Symfony\Component\DependencyInjection\ServiceLocator" public="true">
            <argument type="collection">
                <argument key="private_alias" type="service" id="private"/>
                <argument key="public_alias" type="service" id="public"/>
            </argument>
        </service>
    </services>
</container>