Neuro-Symbolic Constrained Optimization for Cloud Application Deployment via Graph Neural Networks and Satisfiability Modulo Theory
Madalina Erascu
TL;DR
This work tackles the NP-hard problem of deploying component-based cloud applications by marrying graph-based learning with formal constraint solving. It introduces a neuro-symbolic pipeline where graph neural networks predict edge-type relations in a heterogeneous component–VM graph, and these predictions are integrated as soft constraints within a Z3 SMT solver to guide COP optimization. Through four diverse case studies, the approach demonstrates improved solver scalability and often maintained or enhanced cost-optimal deployments, highlighting the practical viability of neuro-symbolic methods for cloud infrastructure planning. The paper also provides a reusable methodology, datasets, and insights into how GNN architectures and training choices impact scalability and solution quality, along with directions for future enhancements (e.g., advanced GNNs, solver-initialization techniques).
Abstract
This paper proposes a novel hybrid neuro-symbolic framework for the optimal and scalable deployment of component-based applications in the Cloud. The challenge of efficiently mapping application components to virtual machines (VMs) across diverse VM Offers from Cloud Providers is formalized as a constrained optimization problem (COP), considering both general and application-specific constraints. Due to the NP-hard nature and scalability limitations of exact solvers, we introduce a machine learning-enhanced approach where graph neural networks (GNNs) are trained on small-scale deployment instances and their predictions are used as soft constraints within the Z3 SMT solver. The deployment problem is recast as a graph edge classification task over a heterogeneous graph, combining relational embeddings with constraint reasoning. Our framework is validated through several realistic case studies, each highlighting different constraint profiles. Experimental results confirm that incorporating GNN predictions improves solver scalability and often preserves or even improves cost-optimality. This work demonstrates the practical benefits of neuro-symbolic coupling for Cloud infrastructure planning and contributes a reusable methodology for general NP-hard problems.
