Declarative Cluster Management

Summary

Modern cluster management systems like Kubernetes routinely grapple with hard combinatorial optimization problems: load balancing, placement, scheduling, and configuration. Implementing application-specific algorithms to solve these problems is notoriously hard to do, making it challenging to evolve the system over time and add new features.

DCM is a tool to overcome this challenge. It enables programmers to build schedulers and cluster managers using a high-level declarative language (SQL).

Specifically, developers need to represent cluster state in an SQL database, and write constraints and policies that should apply on that state using SQL. From the SQL specification, the DCM compiler synthesizes a program that at runtime, can be invoked to compute policy-compliant cluster management decisions given the latest cluster state. Under the covers, the generated program efficiently encodes the cluster state as an optimization problem that can be solved using off-the-shelf solvers, freeing developers from having to design ad-hoc heuristics.

Code: https://github.com/vmware/declarative-cluster-management/