Currently, when unikernels terminate they just kind of hang forever on GCE instances instead of powering off.

Additionally, when a GCE instance receives a stop command, it sends an ACPI power-off signal to the instance. On Solo5 it appears this is ignored, so the GCE hypervisor waits up to 90 seconds before actually shutting down the instance.

Not sure if this requires a full ACPI implementation that matches the underlying hardware running the server, which would be a huge ordeal, or if GCE provides a more virtualized form that can be harmlessly targeted on non-GCE hosts.