The binpacking algorithm is O(#pending_pods * #new_nodes) and
calculating a very large scale-up can get stuck for minutes or even
hours, leading to CA failing it's healthcheck and going down.
The new limiting prevents this scenario by stopping binpacking after
reaching specified threshold. Any pods that remain pending as a result
of shorter binpacking will be processed next autoscaler loop.
The thresholds used can be controlled with newly introduced flags:
--max-nodes-per-scaleup and --max-nodegroup-binpacking-duration. The
limiting can be disabled by setting both flags to 0 (not recommended,
especially for --max-nodegroup-binpacking-duration).
bsoghigian
Bartłomiej Wróblewski
Daniel Kłobuszewski
Maciek Pytel
weidongcai