multiple libvirt/qemu machines deployed locally leads to ssh connection fail race condition

[NotBrianZach]

I'm trying to deploy locally on nixos using nixops and getting a random failure trying to connect to the qemu vms.
I have tried running nixops deploy with dev-shell of a fork of the most recent nixops (as of this moment), same result (as the earlier nixops v 1.4).

Warning: Permanently added '192.168.122.38' (ED25519) to the list of known hosts.
postgresqlServer> setting state version to 17.03
postgresqlServer> waiting for SSH...
Warning: Permanently added '192.168.122.201' (ED25519) to the list of known hosts.
Permission denied (publickey,password,keyboard-interactive).
apiServer.......> could not connect to ‘root@192.168.122.201’, retrying in 1 seconds...
Warning: Permanently added '192.168.122.156' (ED25519) to the list of known hosts.
Permission denied (publickey,password,keyboard-interactive).
renderServer....> could not connect to ‘root@192.168.122.156’, retrying in 1 seconds...

nixops info looks like this (though sometimes it's only one/none/three machines unknown)

+------------------+----------------------+----------+-------------+-----------------+
| Name             |        Status        | Type     | Resource Id | IP address      |
+------------------+----------------------+----------+-------------+-----------------+
| apiServer        | Unknown / Up-to-date | libvirtd |             | 192.168.122.201 |
| postgresqlServer |   Up / Up-to-date    | libvirtd |             | 192.168.122.38  |
| renderServer     | Unknown / Up-to-date | libvirtd |             | 192.168.122.156 |
+------------------+----------------------+----------+-------------+-----------------+

edit: still looking into this, I think it might be similar problem to https://github.com/NixOS/nixops/pull/364/files

[NotBrianZach]

looks like maybe
https://github.com/NixOS/nixops/blob/master/nixops/backends/libvirtd.py#L87
could be culpable if there's multithreading involved, could get overridden perhaps?
currently trying to write a patch that passes env directly, see if that changes anything