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From "Yan Yan (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-8801) S3's eventual consistent read-after-write may fail yarn deployment of resources to S3
Date Fri, 05 Apr 2019 21:20:00 GMT

    [ https://issues.apache.org/jira/browse/FLINK-8801?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16811267#comment-16811267
] 

Yan Yan commented on FLINK-8801:
--------------------------------

Hi [~NicoK],

I have the same concern. I was using the org.apache.hadoop.fs.s3a.S3AFileSystem provided
by the hadoop-aws package, and still got the failure with your fix. Could you share which
implementation you were using?


I was able to workaround the issue the other way round: by reading the timestamp from S3 and
override the local resource. I think it might be a better fix since it does not reply on any S3AFileSystem
methods. Could you share your thoughts?

Thanks!

> S3's eventual consistent read-after-write may fail yarn deployment of resources to S3
> -------------------------------------------------------------------------------------
>
>                 Key: FLINK-8801
>                 URL: https://issues.apache.org/jira/browse/FLINK-8801
>             Project: Flink
>          Issue Type: Bug
>          Components: Deployment / YARN, FileSystems, Runtime / Coordination
>    Affects Versions: 1.4.0, 1.5.0
>            Reporter: Nico Kruber
>            Assignee: Nico Kruber
>            Priority: Blocker
>             Fix For: 1.4.3, 1.5.0
>
>
> According to https://docs.aws.amazon.com/AmazonS3/latest/dev/Introduction.html#ConsistencyModel:
> {quote}
> Amazon S3 provides read-after-write consistency for PUTS of new objects in your S3 bucket
in all regions with one caveat. The caveat is that if you make a HEAD or GET request to the
key name (to find if the object exists) before creating the object, Amazon S3 provides eventual
consistency for read-after-write.
> {quote}
> Some S3 file system implementations may actually execute such a request for the about-to-write
object and thus the read-after-write is only eventually consistent. {{org.apache.flink.yarn.Utils#setupLocalResource()}}
currently relies on a consistent read-after-write since it accesses the remote resource to
get file size and modification timestamp. Since there we have access to the local resource,
we can use the data from there instead and circumvent the problem.



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