Don't know if it's an option for you, but a quick search shows me Firecracker (an alternative to QEMU) does clean shutdown of VMs when it receives SIGTERM.
- Possible to shut down an s6 service via com... Brett Neumeier via supervision
- Re: Possible to shut down an s6 servic... Carlos Eduardo
- Re: Possible to shut down an s6 se... Laurent Bercot
- Re: Possible to shut down an s6 servic... Dewayne Geraghty
- Re: Possible to shut down an s6 se... Brett Neumeier via supervision
- Re: Possible to shut down an s... Mario Rugiero
- Re: Possible to shut down an s... Jan Braun
- Re: Possible to shut down ... Brett Neumeier via supervision