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https://issues.apache.org/jira/browse/HDFS-6637?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14068350#comment-14068350
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Vinayakumar B commented on HDFS-6637:
-------------------------------------
I think, the configuration "dfs.ha.standby.checkpoints" added to disable the
checkpoints for tests, since the HTTP ports could be specified ephemeral. In
this case Standby NN will not know the Active NN's http port to do checkpoint.
See the comment in MiniDFSCluster
{code} // In an HA cluster, in order for the StandbyNode to perform
checkpoints,
// it needs to know the HTTP port of the Active. So, if ephemeral ports
// are chosen, disable checkpoints for the test.
if (!nnTopology.allHttpPortsSpecified() &&
nnTopology.isHA()) {
LOG.info("MiniDFSCluster disabling checkpointing in the Standby node " +
"since no HTTP ports have been specified.");
conf.setBoolean(DFS_HA_STANDBY_CHECKPOINTS_KEY, false);
}{code}
Even though I agree that user also could disable checkpointing, but I don't
think this is possible in real HA cluster. What user will do with checkpoints
disabled ..? ;)
> Rolling upgrade won't finish if SBN is configured without StandbyCheckpointer
> -----------------------------------------------------------------------------
>
> Key: HDFS-6637
> URL: https://issues.apache.org/jira/browse/HDFS-6637
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 3.0.0
> Reporter: Dian Fu
> Attachments: HDFS-6637.patch, HDFS-6637.patch.1
>
>
> In HA setup cluster, for rolling upgrade, the image file "fsimage_rollback"
> is generated by StandbyCheckpointer thread of SBN. While if configuration
> "dfs.ha.standby.checkpoints" is set false, there will be no
> StandbyCheckpointer thread in SBN. This will lead to the rolling upgrade
> never finish.
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