The ceasefire is probably sustainable for the next five years, the term of the agreement. Russian peacekeepers were quickly put into place, and unlike previous attempts at ceasefires, this one appears to be holding.
There are numerous problems, including the fact that it appears Azerbaijan is still holding Armenian prisoners of war and civilians are still being prevented from having freedom of movement. There are property restitution issues, but by and large the ceasefire is holding and is proving effective.