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https://issues.apache.org/jira/browse/HDFS-12357?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16149947#comment-16149947
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Chris Douglas commented on HDFS-12357:
--------------------------------------
Sorry to be dense, but why can't this live in the external attribute provider?
{{NameNode::getRemoteUser}} is not only public, it's a 2-line method calling
stable APIs. Given:
{code:java}
INodeAttributes getAttributes(INodesInPath iip)
throws FileNotFoundException {
INode node = FSDirectory.resolveLastINode(iip);
int snapshot = iip.getPathSnapshotId();
INodeAttributes nodeAttrs = node.getSnapshotINode(snapshot);
if (attributeProvider != null) {
// permission checking sends the full components array including the
// first empty component for the root. however file status
// related calls are expected to strip out the root component according
// to TestINodeAttributeProvider.
byte[][] components = iip.getPathComponents();
components = Arrays.copyOfRange(components, 1, components.length);
nodeAttrs = attributeProvider.getAttributes(components, nodeAttrs);
}
return nodeAttrs;
}
{code}
can't {{attributeProvider}} return the formal {{nodeAttrs}} unmodified after
performing the same logic as {{NameNode::getRemoteUser}}?
> 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-12357.001.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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