If some sort of debugging is going on which doubts topological misconfiguration, you anyway need to check all the namenodes, if one namenode is misconfigured and if another is not. Maybe the issue won't surface if the properly configured namenode is the Active namenode at that time, but one failover can screw things up.
Secondly, checking the topology to triage a potential issue which doubts rack misconfiguration just by checking Active namenode itself isn't a complete solution, what if when the issue occurred the present standby namenode was active then. In such cases anyway you have to check all the Namenodes. Getting Topology from Individual Namenodes is a doable task for any Admin & isn't as such difficult. If that wasn't naive to do so, We could have explored getting Topology from all the namenodes as part of DebugAdmin commands maybe.... -Ayush On Thu, 10 Nov 2022 at 15:45, 尉雁磊 <[email protected]> wrote: > > > So what you are saying is that this is a management issue, not a code > issue. Even if the manager has misdeployed the rack perception of namnode, > the manager will not be able to locate the actual problem from the log and > will only be able to check whether the deployment operation is correct。 > > > > > At 2022-11-10 17:34:37, "Ayush Saxena" <[email protected]> wrote: > > In a stable cluster, usually all the datanodes report to all the namenodes > and mostly the information would be more or less same in all namenodes. > This isn't data which goes stale you might land up in some mess, and > moreover these aren't user commands but Admin commands, it is pre assumed > that the admin would be having idea about the system and how it behaves, > and there are ways to get this detail from a specific Namenode, it can be > done if required, even each namenode UI gives details about the datanode > states and so. > > From the code point of view, I don't think it is a good idea to change or > something which is gonna get accepted. > > -Ayush > > On Thu, 10 Nov 2022 at 13:53, 尉雁磊 <[email protected]> wrote: > >> hdfs dfsadmin -printTopology Always get information from this namenode >> in the cluster，Whether the namenode is active or standby，I don't think >> this is normal, this command should always get information from the active >> namenode！ >> >
