如何解决Kubernetes Federation v2中的标志重新定义错误？

I'm following the kubefed2 user guide to deploy a multi-clusters federation. When I ran the command ./bin/kubefed2 join cluster1 --cluster-context cluster1 --host-cluster-context cluster1 --add-to-registry --v=2 to join a cluster into the federation, I got an Flag refined error.

Error Msg:

./bin/kubefed2 join cluster2 --cluster-context cluster2 \
>     --host-cluster-context cluster1 --add-to-registry --v=2
./bin/kubefed2 flag redefined: log_dir
panic: ./bin/kubefed2 flag redefined: log_dir

goroutine 1 [running]:
flag.(*FlagSet).Var(0xa896000, 0x90a5d40, 0xa965508, 0x8f236d5, 0x7, 0x8f5110b, 0x2f)
    /usr/local/go/src/flag/flag.go:805 +0x43b
flag.(*FlagSet).StringVar(0xa896000, 0xa965508, 0x8f236d5, 0x7, 0x0, 0x0, 0x8f5110b, 0x2f)
    /usr/local/go/src/flag/flag.go:708 +0x6a
flag.(*FlagSet).String(0xa896000, 0x8f236d5, 0x7, 0x0, 0x0, 0x8f5110b, 0x2f, 0xa965500)
    /usr/local/go/src/flag/flag.go:721 +0x67
flag.String(0x8f236d5, 0x7, 0x0, 0x0, 0x8f5110b, 0x2f, 0x0)
    /usr/local/go/src/flag/flag.go:728 +0x53

Golang Version:go version go1.11.5 linux/386

Can anybody tell me how to solve this problem?