user

I have no name

IPC

ipcs -q
ipcmk -Q

PID:

echo $$

mount:

mount -t proc proc /proc

UTS

pstree -pl

readlink /proc/111/ns/uts
readlink /proc/123/ns/uts

hostname test-hostname-01
hostname

---

enable user name space on centos:

grubby --args="user_namespace.enable=1" --update-kernel="$(grubby --default-kernel)"
reboot
echo 640 > /proc/sys/user/max_user_namespaces

disable

grubby --remove-args="user_namespace.enable=1" --update-kernel="$(grubby --default-kernel)"
reboot