You suspect many Compute Engine instances used for video encoding are idle zombies. What’s the quickest way to list idle VM instances?

The gcloud recommender command, specifically the google.compute.instance.IdleResourceRecommender insight type, is designed to identify idle Compute Engine instances. This is the quickest and most direct way to find zombie VMs as it leverages Google Cloud's built-in recommendation engine. Logging into each instance is time-consuming and inefficient for many VMs. The idle:true label is not automatically set by Google Cloud for idle instances; it would require manual labeling. While health checks can indicate unresponsive instances, they don't directly identify idle VMs that might still be technically "healthy" but unused, and this method is specific to managed instance groups, not all Compute Engine instances.