[
https://issues.apache.org/jira/browse/HDFS-5138?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13883110#comment-13883110
]
Suresh Srinivas commented on HDFS-5138:
---------------------------------------
[~atm], please address the comments before merging to branch-2.
My main concern apart from comments on the code is, the need to have all JNs
and when any of the steps related to a JN fails, the boundary conditions that
arise out of it. These issues can result in loss of metadata and very involved,
error prone recovery procedure. It also might need the system to be restarted
(say finalize fails because one of the JNs is not up). Please look at the
comments on the design and see if I understand it correctly.
> Support HDFS upgrade in HA
> --------------------------
>
> Key: HDFS-5138
> URL: https://issues.apache.org/jira/browse/HDFS-5138
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 2.1.1-beta
> Reporter: Kihwal Lee
> Assignee: Aaron T. Myers
> Priority: Blocker
> Attachments: HDFS-5138.patch, HDFS-5138.patch, HDFS-5138.patch,
> HDFS-5138.patch, HDFS-5138.patch, HDFS-5138.patch, HDFS-5138.patch,
> HDFS-5138.patch, HDFS-5138.patch, HDFS-5138.patch, HDFS-5138.patch,
> hdfs-5138-branch-2.txt
>
>
> With HA enabled, NN wo't start with "-upgrade". Since there has been a layout
> version change between 2.0.x and 2.1.x, starting NN in upgrade mode was
> necessary when deploying 2.1.x to an existing 2.0.x cluster. But the only way
> to get around this was to disable HA and upgrade.
> The NN and the cluster cannot be flipped back to HA until the upgrade is
> finalized. If HA is disabled only on NN for layout upgrade and HA is turned
> back on without involving DNs, things will work, but finaliizeUpgrade won't
> work (the NN is in HA and it cannot be in upgrade mode) and DN's upgrade
> snapshots won't get removed.
> We will need a different ways of doing layout upgrade and upgrade snapshot.
> I am marking this as a 2.1.1-beta blocker based on feedback from others. If
> there is a reasonable workaround that does not increase maintenance window
> greatly, we can lower its priority from blocker to critical.
--
This message was sent by Atlassian JIRA
(v6.1.5#6160)
