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https://issues.apache.org/jira/browse/HADOOP-9629?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14014377#comment-14014377
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Chris Nauroth commented on HADOOP-9629:
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[~mikeliddell], and everyone involved, this is very nice work. Thank you all
for the contribution.
I've completed a pass through the whole patch, and overall it looks good. I
ran the test suites successfully against an Azure storage account.
Additionally, we have confidence in this code from additional system testing
performed at Microsoft and Hortonworks during the past year (maybe longer).
Please refer to the ReviewBoard link for feedback on a couple of points in the
code. Let's try to address these points before committing.
Additionally, we ask that new classes have appropriate annotations for
{{InterfaceAudience}} and {{InterfaceStability}}. My suggestion on this is:
* {{NativeAzureFileSystem}} gets {{InterfaceAudience#Public}} and
{{InterfaceStability#Stable}} (by extension of the fact that the base
{{FileSystem}} class is categorized this way).
* {{Wasb}} gets {{InterfaceAudience#Public}} and
{{InterfaceStability#Evolving}}. (Again, this falls from how its base class is
categorized.)
* All other classes get {{InterfaceAudience#Private}}. You can skip the
{{InterfaceStability}} annotation for these, because when the audience is
private, it is assumed that there is no stability guarantee.
* These annotations are only necessary for main classes, not test classes.
Let me know whether or not you agree that classification makes sense.
bq. -1 javadoc. The javadoc tool appears to have generated 100 warning messages.
The patch actually introduced just 1 new JavaDoc warning, which I mentioned in
the ReviewBoard feedback. For some reason, it flagged a bunch of unrelated
things under hadoop-common, so maybe this is a bug in our automation.
> Support Windows Azure Storage - Blob as a file system in Hadoop
> ---------------------------------------------------------------
>
> Key: HADOOP-9629
> URL: https://issues.apache.org/jira/browse/HADOOP-9629
> Project: Hadoop Common
> Issue Type: Improvement
> Reporter: Mostafa Elhemali
> Assignee: Mike Liddell
> Attachments: HADOOP-9629 - Azure Filesystem - Information for
> developers.docx, HADOOP-9629 - Azure Filesystem - Information for
> developers.pdf, HADOOP-9629.2.patch, HADOOP-9629.3.patch, HADOOP-9629.patch,
> HADOOP-9629.trunk.1.patch, HADOOP-9629.trunk.2.patch
>
>
> h2. Description
> This JIRA incorporates adding a new file system implementation for accessing
> Windows Azure Storage - Blob from within Hadoop, such as using blobs as input
> to MR jobs or configuring MR jobs to put their output directly into blob
> storage.
> h2. High level design
> At a high level, the code here extends the FileSystem class to provide an
> implementation for accessing blob storage; the scheme wasb is used for
> accessing it over HTTP, and wasbs for accessing over HTTPS. We use the URI
> scheme: {code}wasb[s]://<container>@<account>/path/to/file{code} to address
> individual blobs. We use the standard Azure Java SDK
> (com.microsoft.windowsazure) to do most of the work. In order to map a
> hierarchical file system over the flat name-value pair nature of blob
> storage, we create a specially tagged blob named path/to/dir whenever we
> create a directory called path/to/dir, then files under that are stored as
> normal blobs path/to/dir/file. We have many metrics implemented for it using
> the Metrics2 interface. Tests are implemented mostly using a mock
> implementation for the Azure SDK functionality, with an option to test
> against a real blob storage if configured (instructions provided inside in
> README.txt).
> h2. Credits and history
> This has been ongoing work for a while, and the early version of this work
> can be seen in HADOOP-8079. This JIRA is a significant revision of that and
> we'll post the patch here for Hadoop trunk first, then post a patch for
> branch-1 as well for backporting the functionality if accepted. Credit for
> this work goes to the early team: [~minwei], [~davidlao], [~lengningliu] and
> [~stojanovic] as well as multiple people who have taken over this work since
> then (hope I don't forget anyone): [~dexterb], Johannes Klein, [~ivanmi],
> Michael Rys, [~mostafae], [~brian_swan], [~mikelid], [~xifang], and
> [~chuanliu].
> h2. Test
> Besides unit tests, we have used WASB as the default file system in our
> service product. (HDFS is also used but not as default file system.) Various
> different customer and test workloads have been run against clusters with
> such configurations for quite some time. The current version reflects to the
> version of the code tested and used in our production environment.
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