Comment 3 for bug 1537078

I don't think this is related to bug 1419041.

The KeyError is arising from looking into a dict that's derived from a query to all connected clusters. It's something like: ask all clusters what power drivers they have, then merge.

I suspect there were, at the moment this exception occurred, no clusters connected.

There's certainly a problem here, which may or may not be a bug in MAAS — it could be a network problem, or the cluster was rebooting, for example — and I suspect this bug is a misleading symptom of that underlying problem.