ScrumMaster
Scrum is facilitated by a ScrumMaster, also written as Scrum Master, who is accountable for removing impediments to the ability of the team to deliver the sprint goal/deliverables. The ScrumMaster is not the team leader but acts as a buffer between the team and any distracting influences. The ScrumMaster ensures that the Scrum process is used as intended. The ScrumMaster is the enforcer of rules. A key part of the ScrumMaster’s role is to protect the team and keep them focused on the tasks at hand. The role has also been referred to as servant-leader to reinforce these dual perspectives.
Скрам это методология гибкой разработки, у нас не совсем скрам у нас аджайл (аджайл родился на основе нескольких методологий в том числе и скрама), но роль скрам-мастера такая же как и в скраме
спринт это одна итерация разработки, может быть месяц может 2 недели, как решит команда.