This document provides solutions to common issues you might encounter whenupdating a Compute Engine VM instance. For general instructions on how toupdate a VM, seeUpdate instance properties.

Best practices

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

• Use theupdate-from-file workflow: Export the instance configuration to afile, modify the file, and then use thegcloud compute instances update-from-file command to apply the changes. Thisapproach helps prevent errors from manual commands.

• Use themost-disruptive-allowed-action flag: This flag prevents accidentalrestarts. Set it toNO_EFFECT to test your changes,REFRESH fornon-disruptive updates, andRESTART only when you are sure a restart isacceptable.

Common issues

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

Metadata fingerprint mismatch

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

Error message:

Supplied fingerprint does not match current metadata fingerprint

Resolution:

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

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

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

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