Setting limits is important, but it always has been. Kubernetes nodes typically don't have a swap so without setting container limits, some critical process can OOM. With swap enabled, memory grows > pathological swapping ensures => caches get dropped making disk performance suck, and all the while your system is shuffling pages between memory and disk. So of course load hits 50+ and the machine turns into a 'black hole'. I've even seen a single VM do that, and cause so much disk IO that it took out the whole hypervisor (which had a single RAID volume)