Calculating spare pod estimates
Spare pods calculation
Spare pods are computed by using the resource consumption of a typical pod in the cluster. The following table lists formulas that lead up to the spare pod calculation.
Metric | Description | Formula | |
|---|---|---|---|
CPU_UTIL | CPU utilization of the cluster | CPU_UTIL = (CPU_USED_NUM / CPU_NUM) * 100 | |
CPU_REQUEST_CAPACITY | Percentage of CPUs requested with respect to CPU capacity (number of CPUs). | CPU_REQUEST_CAPACITY = (CPU_REQUEST / CPU_NUM) * 100 | |
MEM_UTIL | Memory utilization of the cluster | MEM_UTIL = (MEM_REAL_USED / TOTAL_REAL_MEM) * 100 or (MEM_UTIL / TOTAL_REAL_MEM) *100 | |
MEM_REQUEST_CAPACITY | Percentage of memory requested with respect to memory capacity (total memory). | MEM_REQUEST_CAPACITY = (MEM_REQUEST / TOTAL_REAL_MEM) * 100 | |
POD_QUOTA_USED | Percentage of pod quota used | POD_QUOTA_USED = (KPOD_NUM/KPOD_NUM_MAX) * 100 | |
MAX_USAGE | Maximum usage value among the metrics used in the formula. | MAX_USAGE = (CPU_UTIL, CPU_REQUEST_CAPACITY, MEM_UTIL, MEM_REQUEST_CAPACITY, POD_QUOTA_USED) | |
RESIDUAL_CAPCITY_OF_CLUSTER | Total amount of residual or spare capacity of a cluster | RESIDUAL_CAPCITY_OF_CLUSTER = 100 - MAX_USAGE | |
USAGE_OF_TYPICAL_POD | Resource usage of a typical pod | USAGE_OF_TYPICAL_POD = MAX_USAGE / KPOD_NUM | |
SPARE_PODS | Number of spare pods | SPARE_PODS = RESIDUAL_CAPCITY_OF_CLUSTER / USAGE_OF_TYPICAL_POD | |