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https://issues.apache.org/jira/browse/HDFS-2354?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13135205#comment-13135205
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Suresh Srinivas commented on HDFS-2354:
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bq. The implementation in HDFS-1974 has the drawback that Namenode /
NamenodeRpcServer implements HAServiceProtocol, which is against the goal of
HDFS-1623 to build a framework for HA.
Can you explain hot it is against the goal of HDFS-1623? I think you may be
misunderstanding HAServiceProtocol's intent. HAServiceProtocol allows Namenode
to be treated as a resource. Whether it is CRM+LRM from Linux HA or
FailoverController, both need this. This is irrespective of where
FailoverController sits - as a separate daemon or a module inside the namenode
process.
I have been very confused by neutral state and how it avoids the need for
fencing. If you create a detailed write up on this aspect, I am willing to
spend some time on that.
> Generalize the HAServiceProtocol interface
> ------------------------------------------
>
> Key: HDFS-2354
> URL: https://issues.apache.org/jira/browse/HDFS-2354
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: name-node
> Reporter: Justin Joseph
> Assignee: Justin Joseph
> Attachments: HAService_fw_Class_Diagram.JPG, HDFS-2354.1.patch,
> HDFS-2354.patch
>
>
> This JIRA intends to revisit the patches committed for HADOOP-7455 and
> HDFS-1974 & to provide more generic interfaces which allows alternative HA
> implementations to co-exist complying with HAServiceProtocol.
> Some of the considerations are
> 1) Support life cycle methods (start*() and stop() APIs) in HAServiceProtocol
> 2) Support custom states in HAServiceProtocol
> 3) As per the patch submitted for HDFS-1974, Namenode implements HAService
> interface. This needs to be reconsidered.
> I will elaborate on these points, in the form of comments below.
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