docker_nproc_ulimit.md

docker --version 
Docker version 1.13.1, build 092cba3

• start a docker container (ubuntu)

docker run -it ubuntu bash
 
root@1834dea29581:/# apt-get update
root@1834dea29581:/# apt-get install vim -y
root@1834dea29581:/# adduser --home /home/foo foo
root@1834dea29581:/# su - foo
foo@1834dea29581:~$ touch test.sh
foo@1834dea29581:~$ chmod 755 test.sh
foo@1834dea29581:~$ vim test.sh

• in test.sh :

#!/bin/bash
count=0
 
while true
do
  echo $count
  sleep 100 &
  count=$[$count+1]
done

• find the number of processes your user is running right now on your host (not in the container)

ps -eLf | grep ${LOGNAME}|wc -l
 
1245

• In the container, set a limit for the user (as root) and give a little bit overhead :

root@1834dea29581:/# echo "*          soft    nproc     1089" >  /etc/security/limits.d/90-nprocs.conf

• start the test :

root@1834dea29581:/# su - foo
foo@1834dea29581:~$ ./test.sh         
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./test.sh: fork: retry: Resource temporarily unavailable
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./test.sh: fork: retry: Resource temporarily unavailable
^C^C./test.sh: fork: retry: Resource temporarily unavailable
^C^C./test.sh: fork: retry: Resource temporarily unavailable