minimalAction

Minimal action to be taken on an instance. Use this option to minimize disruption as much as possible or to apply a more disruptive action than is necessary. - To limit disruption as much as possible, set the minimal action to REFRESH. If your update requires a more disruptive action, Compute Engine performs the necessary action to execute the update. - To apply a more disruptive action than is strictly necessary, set the minimal action to RESTART or REPLACE. For example, Compute Engine does not need to restart a VM to change its metadata. But if your application reads instance metadata only when a VM is restarted, you can set the minimal action to RESTART in order to pick up metadata changes.