How to check the number of cores used by docker container?

Question

I have been working with Docker for a while now, I have installed docker and launched a container using

docker run -it --cpuset-cpus=0 ubuntu

When I log into the docker console and run

grep processor /proc/cpuinfo | wc -l

It shows 3 which are the number of cores I have on my host machine.

Any idea on how to restrict the resources to the container and how to verify the restrictions??

Answer 1

The issue has been already raised in #20770. The file /sys/fs/cgroup/cpuset/cpuset.cpus reflects the correct output.

The cpuset-cpus is taking effect however is not being reflected in /proc/cpuinfo