Centos Docker container su: cannot open session: Permission denied

Issue: After an software update in a Centos 7 docker container `su – user` is no longer possible with the following error

bash-4.2# su - username
Last login: Wed Sep 13 13:20:31 UTC 2017
su: cannot open session: Permission denied

Inappropriate settings of nofile in either in




There are several solution, which suggest removing nofile unlimited like editing limits.conf and Redhat proposed solution.

However there are also files under /etc/security/limits.d/, where you need to fix nofile references as well. Where you need to change it from unlimited or a number like 500000 to 65536 or less.

bash-4.2# cat /etc/security/limits.d/50-open-files.conf
*         hard    nofile      500000
*         soft    nofile      500000

Need to be edited to become:

bash-4.2# cat /etc/security/limits.d/50-open-files.conf
*         hard    nofile      65536
*         soft    nofile      65536