coredns/plugin/traffic/xds_bootstrap_insecure.json

{
        "node": {
                "id": "COREDNS_NODE_ID",
                "metadata": {
                    "TRAFFICDIRECTOR_GRPC_HOSTNAME": "xds_cluster"
            }
        },
        "xds_servers" : [{
                "server_uri": "localhost:18000"
        }]
}