Hi @ntho,
Based on the previous threads @ignoramous helpfully linked, it does seem that the Nomad-based scheduler hasn’t always spread instances evenly across configured regions as expected.
The Nomad scheduler considers several combined factors when making placement decisions, so it might be that some of the other regions were closer to their capacity limits. Or it could be some other bug in Nomad or our configuration that we haven’t tracked down yet.
We’re working on replacing the Nomad scheduler with our own Machine-based scheduler, which will eventually give us more control and working knowledge of the internals, making it easier for us to track down scaling/placement issues. Until then, you can try using --max-per-region as suggested to manually spread out instances, though that won’t be too useful if you also want to autoscale beyond current instance counts.