The Buddha is the Teacher (sattha) but there is no Guru in Buddhism. A new monk has to live with his preceptor (upajjhaya) or mentor (acariya) who are supposed to pass on knowledge of Dhamma-Vinaya to him, so that he can live independently after that. The story of Second Council: what has been habitually practised (acinnakappa) by one's teacher is not automatically allowable.
