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From "Konstantin Shvachko (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-4618) Move http server from FSNamesystem into NameNode.
Date Fri, 07 Nov 2008 22:31:44 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-4618?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12645895#action_12645895
] 

Konstantin Shvachko commented on HADOOP-4618:
---------------------------------------------

I came to this conclusion trying to implement a standby node. SNN and NN should be represented
by the same class, since one can turn into another and vice versa during their life time.
I realized that with current implementation the node startup logic will be spread between
two classes ({{NameNode}} and {{FSNamesystem}}), which is inconvenient, complex, and error
prone.

One of the consequences of the current design is that we expose {{FSNamesystem}} to jsp-s
and servlets through a static public method {{getFSNamesystem()}}, which returns {{this}}.
This seems to be an unnecessary shortcut, because all jsp-s and servlets have a reference
to the {{NameNode}} instance and can access {{FSNamesystem}} data via name-node. 
This also creates redundant fields in  {{FSNamesystem}} like name-node's host, port and infoPort.

> Move http server from FSNamesystem into NameNode.
> -------------------------------------------------
>
>                 Key: HADOOP-4618
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4618
>             Project: Hadoop Core
>          Issue Type: Improvement
>          Components: dfs
>    Affects Versions: 0.1.0
>            Reporter: Konstantin Shvachko
>            Assignee: Konstantin Shvachko
>             Fix For: 0.20.0
>
>
> NameNode is responsible now for starting its RPC server. The (web UI) http server is
started inside FSNamesystem class.
> I think it should be the NameNode's responsibility to deal with all issues intended for
exposing information it holds to the outside world. This should include the RCP server as
well as the http server.
> And FSNamesystem class should be a logical container of internal namespace data-structures
and in general should not be accessed directly from the outside.

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