How can i check my created namespace?

Question

Using clone() or unshare(), we can create a network namespace. Just as the command:

ns_exec -nm -- /bin/bash

(see http://lxc.sourceforge.net/index.php/about/kernel-namespaces/network/configuration/)

If I have created several network namespaces with ns_exec command, where can I see them? or How can i count the numbers of network namespaces?

Answer 1

You observe them indirectly. Say, lo devices are independent, iptables rules are independent and so on.

netns objects live in it's own kmem_cache: grep net_namespace /proc/slabinfo

But this is unreliable way to count them, as SLUB can share caches.

There is no /proc file or something dedicated specifically as netns counter.