unshare -fn sleep 60
ps -ef|grep sleep
root 32882 4935 0 10:00 pts/0 00:00:00 unshare -fn sleep 60
root 32883 32882 0 10:00 pts/0 00:00:00 sleep 60
lsns -t net
4026532508 net 2 32882 root unassigned unshare
nsenter -t 32882 -n ip a
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00