Vertex AI Workbench instances with idle shutdown turned off
What does ZopNight detect here?
Vertex AI Workbench shuts an instance down after 180 inactive minutes by default, and turning that off leaves vCPU, GPU and memory billing through nights and weekends. ZopNight flags Workbench instances with idle shutdown disabled and prices the saving from the instance's measured off-hours idle share, not from a fixed guess.
Signal and threshold
| Field | Value |
|---|---|
| Rule IDs | RC-1235 |
| Category | schedule |
| Severity | medium |
| Metric | none — pure configuration read |
| Threshold | idle shutdown disabled |
| Source | ZopNight |
| Permissions used | notebooks.instances.list · notebooks.instances.get · monitoring.timeSeries.list |
Where it applies
Idle shutdown is the notebook’s built-in cost control
Google’s idle shutdown page describes the default: Workbench instances shut down after 180 minutes with no kernel activity, and the console accepts any value from 10 to 1440 minutes. Once an instance is shut down it stops accruing CPU and GPU charges. When someone disables the feature, a GPU notebook left open on a Friday afternoon runs until Monday.
Idle means kernel activity specifically. Running a cell or printing output resets the timer; CPU usage on its own does not, and an open but untouched JupyterLab tab does not keep the instance alive.
Checking the setting on your instances
gcloud workbench instances list --location=us-central1-agcloud workbench instances describe INSTANCE_NAME --location=us-central1-aIn the describe output, the idle-timeout-seconds key in the instance metadata holds the
timeout. An empty value means idle shutdown is off.
The two inputs behind a finding
ZopNight first confirms from the instance’s configuration that idle shutdown is disabled. It then uses the instance’s usage heatmap, built from its own metrics, to measure what share of the week the notebook sits idle. Both are required.
Notebooks without a measured idle window
If the configuration does not clearly say idle shutdown is off, nothing is flagged. If there is no heatmap data yet, or the measured idle share is zero, ZopNight stays silent rather than applying a flat estimate, and it never files a $0 governance card in place of a cost finding.
Idle share times monthly cost
saving = monthly instance cost x measured idle share of the weekcost after fix = monthly instance cost - savingDisk charges continue while the instance is shut down, so they stay in the cost after the fix.
Turning idle shutdown back on
- Ask the owner whether any work depends on the notebook staying up with no kernel activity.
- Set a timeout in seconds, for example three hours:
gcloud workbench instances update INSTANCE_NAME --location=us-central1-a --metadata=idle-timeout-seconds=10800. - Check that guest attributes are enabled on the instance; Google lists them as a requirement for idle shutdown to run.
- Alternatively, apply the off-hours schedule ZopNight proposes from the recommendation.