[ 1082.488143][T11097] Could not find device with ifindex 2000 in netnsfd 11 [ 1082.488794][T11097] Could not find netns with fd: 2000 [ 1082.489331][T11097] Cannot link a netdevsim to itself [ 1082.489990][T11097] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).