To start a container Docker does a lot of expensive setup like preparing network stack, volumes, logging etc. One can trivially see how expensive is that just b

To start a container Docker does a lot of expensive setup like preparing network stack, volumes, logging etc. One can trivially see how expensive is that just by timing the command line and dropping expensive Docker options. On my laptop: $ time docker run --rm ubuntu true real 0m0.641s user 0m0.036s sys 0m0.018s $ time docker run --rm --net none --log-driver none --read-only ubuntu true real 0m0.399s user 0m0.039s sys 0m0.018s Compare that with the unshare utility that one can use as a Docker replacement for simple containers (options create all new namespaces that the utility supports including user namespaces): $ time unshare -m -u -i -n -p -U -C -f -r /bin/true real 0m0.029s user 0m0.001s sys 0m0.009s