[ 486.689979] Could not find device with ifindex 2000 in netnsfd 11 [ 486.690138] Could not find netns with fd: 2000 [ 486.690222] Cannot link a netdevsim to itself [ 486.690320] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).