Current Observer only has a symlink for cluster config /d2/clusters/$xxxMaster, but not a counterpart symlink for uri parent /d2/uris/$xxxMaster. In fact, since cluster symlink and uri parent symlink always point to the same actual node name, and it's a redundancy and a burden for the symlink-update tool to maintain two symlinks for the same actual node name.
We optimize xds flow to use the cluster symlink to listen to the actual nodes for both cluster and uri parent.
Once all apps migrate off ZK flow, we don't need to maintain the uri parent symlink anymore.
Summary
Current Observer only has a symlink for cluster config /d2/clusters/$xxxMaster, but not a counterpart symlink for uri parent /d2/uris/$xxxMaster. In fact, since cluster symlink and uri parent symlink always point to the same actual node name, and it's a redundancy and a burden for the symlink-update tool to maintain two symlinks for the same actual node name. We optimize xds flow to use the cluster symlink to listen to the actual nodes for both cluster and uri parent. Once all apps migrate off ZK flow, we don't need to maintain the uri parent symlink anymore.
Test Done
updated unit tests.