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https://issues.apache.org/jira/browse/HDFS-12357?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16154520#comment-16154520
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Yongjun Zhang commented on HDFS-12357:
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Many thanks [~chris.douglas] for the offline discussions!
Good summary! I can create a jira for more general solution, we can work on the
jira when there is a new use case coming up, such as filtering by path or by
the combination of user/path. I think the new solution can be stacked on top of
the fix of this jira.
I checked with folks around and we agreed that for the dedicated user we can
bypass external provider when doing permission checking. This means the
permission checking will be using HDFS metadata. Welcome to comment If other
folks have any.
Thanks again!
> Let NameNode to bypass external attribute provider for special user
> -------------------------------------------------------------------
>
> Key: HDFS-12357
> URL: https://issues.apache.org/jira/browse/HDFS-12357
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Yongjun Zhang
> Assignee: Yongjun Zhang
> Attachments: HDFS-12357.001a.patch, HDFS-12357.001b.patch,
> HDFS-12357.001.patch, HDFS-12357.002.patch, HDFS-12357.003.patch,
> HDFS-12357.004.patch, HDFS-12357.005.patch
>
>
> This is a third proposal to solve the problem described in HDFS-12202.
> The problem is, when we do distcp from one cluster to another (or within the
> same cluster), in addition to copying file data, we copy the metadata from
> source to target. If external attribute provider is enabled, the metadata may
> be read from the provider, thus provider data read from source may be saved
> to target HDFS.
> We want to avoid saving metadata from external provider to HDFS, so we want
> to bypass external provider when doing the distcp (or hadoop fs -cp)
> operation.
> Two alternative approaches were proposed earlier, one in HDFS-12202, the
> other in HDFS-12294. The proposal here is the third one.
> The idea is, we introduce a new config, that specifies a special user (or a
> list of users), and let NN bypass external provider when the current user is
> a special user.
> If we run applications as the special user that need data from external
> attribute provider, then it won't work. So the constraint on this approach
> is, the special users here should not run applications that need data from
> external provider.
> Thanks [~asuresh] for proposing this idea and [~chris.douglas], [~daryn],
> [~manojg] for the discussions in the other jiras.
> I'm creating this one to discuss further.
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