[  228.020219] Could not find device with ifindex 2000 in netnsfd 11
[  228.020344] Could not find netns with fd: 2000
[  228.020416] netdevsim netdevsim437 eth0: Cannot link a netdevsim to itself
[  228.020502] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).