make supported interfaces configurable

[Garrybest]

Signed-off-by: Garrybest garrybest@foxmail.com

Now we only get local IP from eth0 and ib0. However, in my cloud environment, all containers are using eth1 as their network interface. So I think we'd better make supported interfaces configurable.

[Garrybest]

cc @evelynl94

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