[  227.730540] Could not find device with ifindex 2000 in netnsfd 11
[  227.730684] Could not find netns with fd: 2000
[  227.730763] netdevsim netdevsim447 eth0: Cannot link a netdevsim to itself
[  227.730881] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).