[  495.043853] Could not find device with ifindex 2000 in netnsfd 11
[  495.043999] Could not find netns with fd: 2000
[  495.044097] netdevsim netdevsim357 eth0: Cannot link a netdevsim to itself
[  495.044215] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).