# Chalk Machine Type defaults
source: https://docs.chalk.ai/docs/chalk-machine-type-catalog

## Search default primary instances and ordered fallbacks by cloud provider, workload, and Chalk Machine Type.

Use this catalog to find the default primary instance and ordered fallbacks for
Chalk Machine Types across cloud providers. It includes online
workloads without GPUs, offline workloads with disk spilling enabled, and infrastructure
workloads. Fallbacks appear in descending preference order.

Regional availability can remove candidates and promote a fallback to the primary instance.
Cluster and environment overrides can replace the default list. The catalog shows built-in
defaults before regional filtering and overrides.