问题
cAdvisor reports 14GB for the memory used by Prometheus where as top reports 6.xGB.
Can someone explain why this discrepancy?
The documentatation of container_memory_usage_bytes says
Current memory usage in bytes, including all memory regardless of when it was accessed
but it's not clear what this refers to - I assume it's virtual memory size?
As reported by cAdvisor:
core@ip-172-20-100-148 ~ $ curl -q localhost:4194/metrics | grep container_memory_usage_bytes | grep prometheus
container_memory_usage_bytes{container_name="prometheus",id="/docker/d37e7503309e632265cb834095efa949da4dc3c72122cb290e626f1121d0ed6b",image="quay.io/prometheus/prometheus:v1.7.1",name="k8s_prometheus.71f5f8c6_prometheus-zwvhx_xx-system_9753de21-aaac-11e7-97e5-026a05f72f78_4682ea0b",namespace="xx-system",pod_name="prometheus-zwvhx"} 1.4178545664e+10
As reported by top on the host machine:
Tasks: 272 total, 1 running, 271 sleeping, 0 stopped, 0 zombie
%Cpu(s): 20.2 us, 2.7 sy, 0.0 ni, 75.9 id, 0.5 wa, 0.6 hi, 0.1 si, 0.0 st
KiB Mem: 65964640 total, 64892592 used, 1072048 free, 5222520 buffers
KiB Swap: 0 total, 0 used, 0 free. 4737420 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
118446 root 20 0 6783108 6.154g 19864 S 316.7 9.8 8241:05 prometheus
回答1:
Per the discussion here, cAdvisor reports a total memory usage in bytes.
In your case, cAdvisor was reporting 1.4178545664e+10 Byte = 14.178545664 Gigabyte. Note it was e+10 so it is approximately 14G, not 1.4G.
来源：https://stackoverflow.com/questions/46677536/incorrect-reporting-of-container-memory-usage-by-cadvisor