Task failures sometimes can't be understood without looking into agent logs.

Mesos communicates task state transitions via task status updates. They often include a reason, which aims to hint what exactly went wrong. However, these reasons are often:

• misleading
• vague
• generic.
  Needless to say, this complicates triaging why the task has actually failed and hence is a bad user experience. The failures can come from a bunch of different sources: fetcher, isolators (including custom ones!), namespace setup, etc.

This epic aims to improve the UX by providing detailed, ideally typed, information about task failures.