Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/solver-scheduler.

Description:

OpenStack scheduler has nice options like filters which allow resource selection based on simple constraints e.g. Don't put instances in a set on the same host. However for complex constraints, building a filter would be as complex as building a real constraint solver e.g. place VMs while minimizing average (VM-storage-bandwidth) with complex constraints. On the other hand, complex solvers are available in open source (PULP, CVXOPT, COIN_OR). Hence a natural solution to the above problem is to design a pluggable scheduler that leverages existing solvers. We believe that this will open new avenues for complex constraint (and objectives) based resource placement in large OpenStack deployments.

Collaborators:  Yathi Udupi,  Debo Dutta 
Unified Constraints-based Smart Resource Placement: https://docs.google.com/document/d/1IiPI0sfaWb1bdYiMWzAAx0HYR6UqzOan_Utgml5W1HI/edit 

Specification URL (additional information):

https://wiki.openstack.org/wiki/SolverScheduler