The reachability check added with the containerisation fix was itself
racy and went red on one of two legs of the same GitHub run: k3d's
--wait returns when the node container reports ready, but the API
server can still answer discovery with 503 for a moment after that, and
kubectl cluster-info asked exactly once. A check that produces sporadic
red is worse than no check - that is the one property #227 rules out
explicitly. It now polls kubectl get nodes, which is the thing that has
to work and exercises discovery on the way.