Troubleshoot VM updates

This document provides solutions to common issues you might encounter when updating a Compute Engine VM instance. For general instructions on how to update a VM, see Update instance properties.

Best practices

To avoid common issues when updating a VM, follow these best practices:

• Use the update-from-file workflow: Export the instance configuration to a file, modify the file, and then use the gcloud compute instances update-from-file command to apply the changes. This approach helps prevent errors from manual commands.

• Use the most-disruptive-allowed-action flag: This flag prevents accidental restarts. Set it to NO_EFFECT to test your changes, REFRESH for non-disruptive updates, and RESTART only when you are sure a restart is acceptable.

Common issues

This section lists errors you might encounter when updating a VM and provides guidance on how to resolve them.

Metadata fingerprint mismatch

This error occurs when you try to update a VM instance, but the VM's metadata was updated by another process since you last refreshed the page or fetched the instance data.

Error message:

Supplied fingerprint does not match current metadata fingerprint

Resolution:

The instance fingerprint property in your request must match the current fingerprint of the instance to prevent simultaneous update requests from overwriting each other. Try the following:

• Refresh the page: If you're using the Google Cloud console, refresh the VM instance Details page before making your changes.

• Use the --no-etag-cache Google Cloud CLI flag: If you're using the Google Cloud CLI, use the --no-etag-cache flag with your gcloud compute instances update command.

• Retry after a few minutes: As a last resort, try stopping the VM, waiting a few minutes, and then attempt to make the change again.