When the MachineAutoscaler minimum replica count is set higher than the MachineSet's desired replicas, the MachineAutoscaler is expected to maintain at least the minimum replicas regardless of load. However, in certain cases—especially under transient load conditions such as OOM events—the MachineAutoscaler unexpectedly scales below the minimum threshold, likely due to a bug in its logic that allows partial scaling when the load requirement is insufficient to fully meet the minimum. This results in inconsistent scaling behavior that does not align with the expected autoscaler configuration.

    Reproducible when MachineSet replicas are set below the MachineAutoscaler minimum, and transient load or OOM conditions trigger scaling.

    1.Set the MachineSet replicas to a number below the MachineAutoscaler minimum (e.g., MachineSet replicas = 2, MachineAutoscaler minimum = 4).     2. Apply transient load conditions or cause an OOM event in the cluster.     3. Observe if the MachineAutoscaler scales up nodes but fails to reach the minimum replicas, or scales inconsistently with the expected minimum.     

    The MachineAutoscaler scales up nodes below the minimum replica count when transient load conditions or OOM events occur, leading to an inconsistent number of replicas that do not meet the defined minimum.

    The MachineAutoscaler should maintain the number of replicas at or above the minimum count regardless of load conditions, preventing scaling below the specified minimum.