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Resource Solver

1 post · May 2025

What this trail covers

Modal's platform utilizes a sophisticated resource solver, powered by linear programming (LP) and the GLOP solver, to dynamically manage cloud compute resources. This system optimizes instance procurement based on real-time demand, pricing, and availability across multiple cloud providers. It ensures customers receive scalable compute at predictable and favorable prices, while also identifying arbitrage opportunities to reduce operational costs. The solver balances the dual mandates of rapid scaling and cost-optimization, employing heuristics to prune instance types and ensure fast solve times. Observed scaling limits from cloud providers are fed back into the solver for subsequent runs. Background workers request instances based on the solver's output, and report observed limits back.

All Modal trails
  1. Linear programming for fun and profitThis post details the implementation of Modal's resource solver, which uses linear programming (LP) and Google's GLOP solver to manage cloud compute resources. It explains how the solver handles complex demand scenarios, including multiple instance types, GPU fallbacks, and varying user demand, by formulating the problem as an LP. The post highlights the dual mandate of rapid scaling and cost-optimization, and describes how heuristics are used to prune instance types and reduce solve times. It also details the feedback loop where observed scaling limits from cloud providers are incorporated into subsequent solver runs, and how background workers request instances based on the solver's output.