Why Does a Notebook Instance with Custom Specifications Fail to Auto-Stop When Idle?

Symptom

A user creates a notebook instance with custom specifications (for example, 0.5 vCPUs + 1 GiB memory) and enables the auto-stop feature (setting the idle timeout to 15 minutes). However, the instance does not automatically stop as expected after a long period of inactivity.

Possible Causes

The platform determines whether a notebook instance is idle based on whether its resource utilization remains consistently below a predefined threshold. Auto-stop is triggered only when the utilization of key resources (such as CPU and memory) falls below this threshold. When a notebook instance is running, the container itself and basic system services consume a baseline amount of resources. If the custom specifications are very small (e.g., 0.5 vCPUs and 1 GiB memory), this "inherent consumption" accounts for a high percentage of the total allocated resources. Consequently, the overall resource utilization stays above the idle detection threshold even when there is no user activity. As a result, the instance is never flagged as idle and auto-stop is not triggered.

Idle detection thresholds