SystemMemoryExceedsReservation triggered when autoSizingReserved enabled    

    4.16.30

    100%

    1. Enable autoSizingReserved
    2. Add a workload to the cluster
    3. Observe alerts
    

SystemMemoryExceedsReservation

System memory usage of 1.74G on <HOST> exceeds 95% of the reservation. Reserved memory ensures system processes can function even when the node is fully allocated and protects against workload out of memory events impacting the proper functioning of the node. The default reservation is expected to be sufficient for most configurations and should be increased (https://docs.openshift.com/container-platform/latest/nodes/nodes/nodes-nodes-managing.html) when running nodes with high numbers of pods (either due to rate of change or at steady state).
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    No alert

$ oc debug {node} -- chroot /host cat /etc/node-sizing.env'
SYSTEM_RESERVED_MEMORY=1Gi
SYSTEM_RESERVED_CPU=500m
SYSTEM_RESERVED_ES=1Gi

$ oc debug {node} -- chroot /host /usr/local/sbin/dynamic-system-reserved-calc.sh true 1Gi 500m 1Gi

$ oc debug {node} -- chroot /host cat /etc/node-sizing.env'
SYSTEM_RESERVED_MEMORY=17Gi
SYSTEM_RESERVED_CPU=0.35
SYSTEM_RESERVED_ES=1Gi

<REBOOT>

$ oc debug {node} -- chroot /host cat /etc/node-sizing.env'
SYSTEM_RESERVED_MEMORY=1Gi
SYSTEM_RESERVED_CPU=500m
SYSTEM_RESERVED_ES=1Gi



Setting values manually removes the alert
  kubeletConfig:
    systemReserved: 
      cpu: 2000m
      memory: 17Gi
      ephemeral-storage: 1Gi