Description of problem: unsure(1) shows "--user" and "-U" option, while when trying the option, unsure doesn't work. Version-Release number of selected component (if applicable): util-linux-2.23.2-26.el7_2.2.x86_64 How reproducible: Just run the unsure command as follows Steps to Reproduce: 1.sudo yum install util-linux 2.sudo unshare -m -u -i -n -p -f --user --mount-proc bash Actual results: [pkger@dhcp debug]$ sudo unshare -m -u -i -n -p -f --user --mount-proc bash unshare: unshare failed: Invalid argument [pkger@dhcp debug]$ Expected results: A new bash process in the new namespace Additional info:
The user namespaces are "Technology Preview" and disabled by default, see kernel implementation https://bugzilla.redhat.com/show_bug.cgi?id=1138782 If I good remember you need to enable it on kernel command line (something like grubby --args=user_namespace.enable=1 + reboot).