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https://issues.apache.org/jira/browse/HDFS-4521?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13603186#comment-13603186
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Junping Du commented on HDFS-4521:
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For 3. YARN now doesn't cached register nodes into a NetworkTopology tree but
resolve into each RMNode by call RackResolver.resolve() through NM
registration. Thus, it should be different way to tell a topology is invalid or
not to YARN (as no peer nodes to reference), but it is also necessary.
For 4. to test it on an actual cluster may be just simply to use CLI of
"dfsadmin -report"? Also, I remember it used to have "dfsadmin -printTopology"
but cannot find it there now. Do you know where it is going or am I missing
something?
> invalid network toploogies should not be cached
> -----------------------------------------------
>
> Key: HDFS-4521
> URL: https://issues.apache.org/jira/browse/HDFS-4521
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 2.0.5-beta
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Priority: Minor
> Attachments: HDFS-4521.001.patch, HDFS-4521.002.patch,
> HDFS-4521.005.patch, HDFS-4521.006.patch
>
>
> When the network topology is invalid, the DataNode refuses to start with a
> message such as this:
> {quote}
> org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol.registerDatanode from
> 172.29.122.23:55886: error:
> org.apache.hadoop.net.NetworkTopology$InvalidTopologyException: Invalid
> network topology. You cannot have a rack and a non-rack node at the same
> level of the network topology.
> {quote}
> This is expected if you specify a topology file or script which puts leaf
> nodes at two different depths. However, one problem we have now is that this
> incorrect topology is cached forever. Once the NameNode sees it, this
> DataNode can never be added to the cluster, since this exception will be
> rethrown each time. The NameNode will not check to see if the topology file
> or script has changed. We should clear the topology mappings when there is
> an InvalidTopologyException, to prevent this problem.
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