Encontrei isso na falha do servidor. link
Para resumir: Citação do pessoal da AWS:
The Amazon Linux AMI is not based on any one upstream Linux project. That said, one of the goals of the most current Amazon Linux AMI (2013.09) is to be as compatible as possible with RHEL 6. If there are places in which you find that we are not, please let us know so that we can investigate further."