Stéphane Graber (key Incus née LXD contributor) just did a video about developing placement scriptlets in the Starlark language but the interesting thing is, if I'm interpreting what I saw correctly, his cluster was 6 beefy servers plus 3 decent-sized VMs and the idea was, I think, that containers could get placed on the nested VMs, neatly solving the migration issue with containers. The interesting part was it looked like the 3 VMs in the cluster may have been themselves in the cluster.

I could be wrong, though. Interesting approach if true