April 19, 2024

cluster autoscaler

Do you know to what properties of the candidate node group the Kubernetes autoscaler looks at exactly? It scans the node groups and looks at their members’ allocatable capacity and here is an example Node in GCP whose type is n2-standard-8, i.e. 8 CPU and 32GB: Capacity: cpu: 8 ephemeral-storage: 203056560Ki hugepages-1Gi: 0 hugepages-2Mi: 0 memory: 32859412Ki pods: 110 Allocatable: cpu: 7910m ephemeral-storage: 105532546763 hugepages-1Gi: 0 hugepages-2Mi: 0 memory: 29064468Ki pods: 110 If you create a Pod that requests 30Gi of memory, it will not trigger a scale-up because autoscaler doesn’t think that a similar node would be able to accommodate the Pod; it uses allocatable numbers in its calculations.

February 4, 2020

buggy culture

I am really surprised. The release is broken. How could this happen at this point and no one noticed it? Who is responsible for this feature? I really think we should have a meeting to raise awareness about criticality. How is this not tested? Sounds familiar? Software is a living organism that evolves over time and different people contribute to it, leave their marks. When you make a contribution, there are two states that interact with each other.