cpulimiting.md

The key question is "What attributes are you checking on the container's metadata?" We ask because it looks like the only thing modified by passing in --cpu is NanoCpus, not Cpus. We can successfully modify NanoCpus via the AVL application, but your application still complains that the cores count is too high.

A container started from the AVL dashboard:

root@prod-iscgseu1-wharfhouse-0:/home/briandant# swarm inspect learner___138ab157___0 | grep -i cpu
            "Cpus": 32,
            "CpuShares": 0,
            "NanoCpus": 8000000000,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "CpuCount": 0,
            "CpuPercent": 0,

Note that Cpus = 32 and NanoCpus = 8000000000 (or 8**10 in Python's notation.)

Then, we run two containers from Docker's command line client, which bypasses the AVL application:

root@prod-iscgseu1-wharfhouse-0:/home/briandant# docker run -itd --cpus 4 se2019ai:19.3.4
b977830cdeaa3ad528778a31e01dfb55fcf3e9d534903454c597174345520d7a
root@prod-iscgseu1-wharfhouse-0:/home/briandant# docker inspect b977830cdeaa3ad528778a31e01dfb55fcf3e9d534903454c597174345520d7a | grep -i cpu
            "CpuShares": 0,
            "NanoCpus": 4000000000,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "CpuCount": 0,
            "CpuPercent": 0,

In this first container, the Cpus flag is not set, but NanoCpus does respond to the --cpus flag.

On a second container, we see further that the --cpus flag changes NanoCpus:

root@prod-iscgseu1-wharfhouse-0:/home/briandant# docker run -itd --cpus 6 se2019ai:19.3.4
0608d1899a0c64896b321906f9ed2c71102b8f36c4aa8310bff7c1323332f88e
root@prod-iscgseu1-wharfhouse-0:/home/briandant# docker inspect 0608d1899a0c64896b321906f9ed2c71102b8f36c4aa8310bff7c1323332f88e|grep -i cpu
            "CpuShares": 0,
            "NanoCpus": 6000000000,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "CpuCount": 0,
            "CpuPercent": 0,

It is odd that our application sets Cpus and the Docker client does not. I need to look into that. But, I don't want to make a change to the application only to then realize that --cpus only modifies NanoCpus.

1. Can you confirm that you see similar behavior in your environment? What changes when you pass --cpus?
2. Can you explain how you check for the number of cores available? Do you look only at Cpus?