[
https://issues.apache.org/jira/browse/HADOOP-6927?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12910821#action_12910821
]
Konstantin Boudnik commented on HADOOP-6927:
--------------------------------------------
{{DatanodeDescriptor}} is namesystem specific entity. Therefore it seems to be
more appropriate to expose this information via an injected API on namenode
side ((NNProtocol).
If this new API is required to be added via DNClient protocol then its every
invocation will cause a subsequent RPC call. Instead, we can have a method in
NNProtocol which will expose datanodeMap object from where a node descriptor
can be received if a datanode registration is known.
> Herriot NN and DN clients should vend statistics
> ------------------------------------------------
>
> Key: HADOOP-6927
> URL: https://issues.apache.org/jira/browse/HADOOP-6927
> Project: Hadoop Common
> Issue Type: Improvement
> Components: test
> Reporter: Al Thompson
>
> The HDFS web user interface serves useful information through dfshealth.jsp
> and dfsnodelist.jsp.
> The Herriot interface to the namenode and datanode (as implemented in
> NNClient and DNClient, respectively) would benefit from the addition of some
> way to channel this information. In the case of DNClient this can be an
> injected method that returns a DatanodeDescriptor relevant to the underlying
> datanode.
> There seems to be no analagous NamenodeDescriptor. It may be useful to add
> this as a facade to a visitor that aggregates values across the filesystem
> datanodes. These values are (from dfshealth JSP):
> Configured Capacity
> DFS Used
> Non DFS Used
> DFS Remaining
> DFS Used%
> DFS Remaining%
> Live Nodes
> Dead Nodes
> Decommissioning Nodes
> Number of Under-Replicated Blocks
> Attributes reflecting the web user interface header may also be useful such
> as When-Started, Version, When-Compiled, and Upgrade-Status.
> A NamenodeDescriptor would essentially "push down" the code in dfshealth web
> UI behind a more general abstraction. If it is objectionable to make this
> class available in HDFS, perhaps this could be packaged in a Herriot specific
> way.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
