swift-get-nodes extracts the information from the ring and ring only. Essentially it performs the lookup that a proxy or back-end server would do if given the same parameters. Its operation or output may have nothing to do with what is actually going on in the cluster in cases when you neglect to update the ring on the nodes or fail to run the necessary services.

The traditional location for running swift-get-nodes is the same management workstation that runs the builder, and not a cluster node at all.