We are using EKS and we find that when using preferredDuringSchedulingIgnoredDuringExecution doesn’t guarantee scheduling of pods evenly in zone/host. Our situation is that we have 3 zones and 3 EC2 instances in each zone (Min value of our ASG is 9). Though there would be a pod already on a node, scheduler would still schedule a second pod on it while there is another host that doesnt have any pods scheduled on it. Same with zones too, we would notice that only 2 zones get pods scheduled with 1 zone completely ignored.
We need to understand if preferredDuringSchedulingIgnoredDuringExecution guarantees even spread of pods across zones/hosts given the way we are using pod antiaffinity.
Kubernetes version: 1.16
Cloud being used: (put bare-metal if not on a public cloud)
Installation method: EKS
Host OS: Amazon Linux
CNI and version:
CRI and version:
YAML Code snippet