cnitool: https://github.com/xujiyou/blog-data/blob/master/%E4%BA%91%E5%8E%9F%E7%94%9F/Kubernetes/Kubernetes%E6%89%A9%E5%B1%95%E6%9C%BA%E5%88%B6/CNI/cnitool%E4%BD%BF%E7%94%A8%E6%96%B9%E5%BC%8F.md cni spec: https://github.com/containernetworking/cni/blob/main/SPEC.md#Error
