Hide node core count from docker container

6/21/2019

I am currently building a system that run services in individual deployments in a kubernetes cluster and require the limitation of visible cores inside the container.

Node Specs:
8 Cores
16 GB memory

When I deploy, log into the container and inspect the core count with python's multiprocessing module I get the following output:

In [1]: import multiprocessing
In [2]: multiprocessing.cpu_count()
Out[2]: 8

This output is correct seeing that my node has 8 cores.

What I would like is for the container to return a core count of 1 as the core count when running the same multiprocessing.cpu_count() command.

The example use case for this is as follows:

Developer creates an api services running python and gunicorn, gunicorn's default behaviour is to create workers for the number of cores available.

The above will be a problem when the pod is only allowed 100m CPU and 300m Mem as the 8 workers will at some point fill up the memory and the pod will crash, I also would like to hide this for the sake of potential confusion and unexpected behaviour when detecting resources programmatically.

I have tried using the --cpuset-cpus=0 flag as it stood out as a potential solution, but from what I understand and experienced is that this will merely limit the container to the specified core, which does not hide the other 7 cores.

Is there any way of doing this, any help will be appreciated.

-- Illegal Operator
docker
kubernetes
multiprocessing
python

0 Answers