An allusion would mean he is referencing a widely known topic. A simile is a comparison specifically using the words "like" or "as". Personification is the application of Human-like characteristics such as voice or intelligence to something that isn't human. With this example, J.F.K. is describing his inauguration as a new and different era with a comparison between it and a marathon. Though, he didn't use the words "like" or "as" making this a metaphor.
