Move a daily C++ test suite that currently runs for hours on limited on‑prem servers to the cloud, minimizing test changes and overall runtime.

Compute Engine managed instance groups (MIGs) with autoscaling are ideal for this scenario. MIGs allow you to define a template for your test servers, ensuring consistency and easy deployment. Autoscaling dynamically adjusts the number of instances based on demand, providing the necessary compute resources to significantly reduce runtime without over-provisioning. This minimizes test changes as you can lift-and-shift your existing C++ test suite to these instances. Unmanaged instance groups lack autoscaling, meaning you'd have to manually scale, which is inefficient. Cloud Dataproc is for big data processing, not general-purpose C++ test execution. App Engine is a platform-as-a-service for web applications and backends, not suitable for running a C++ test suite directly.