Docker - Container Resource Allocation & cgroups

By default, Docker imposes no restrictions on the amount of system resources that a container can use. 

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Setting resource caps

CPU

Limit CPU core usage:

docker run --cpuset-cpus="0,1" nginx

This restricts the container to only use CPU cores 0 and 1.

Limit CPU usage percentage

docker run --cpus="1.5" nginx

This limits the container to use 1.5 CPUs worth of processing power, even if the host has more.

Memory

Memory restrictions can be implemented using the --memory= flag:

Limit container to 500m:

docker run --memory="500m" nginx

Limit SWAP usage to 1G:

--memory-swap="1g"