[jira] [Commented] (FLINK-21289) Application mode ignores the pipeline.classpaths configuration

["Yang Wang (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-21289?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17429126#comment-17429126 ] 

Yang Wang commented on FLINK-21289:
-----------------------------------

[~PChou] It is really a pity that your PR is not merged eventually. Do you still want to work on this? I could help with review and merging.

> Application mode ignores the pipeline.classpaths configuration
> --------------------------------------------------------------
>
>                 Key: FLINK-21289
>                 URL: https://issues.apache.org/jira/browse/FLINK-21289
>             Project: Flink
>          Issue Type: Bug
>          Components: Client / Job Submission, Deployment / Kubernetes, Deployment / YARN
>    Affects Versions: 1.11.2, 1.12.1
>         Environment: flink: 1.11
> kubernetes: 1.15
>  
>            Reporter: Zhou Parker
>            Assignee: Zhou Parker
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.12.6, 1.13.3, 1.15.0, 1.14.1
>
>         Attachments: 0001-IMP.patch
>
>
> 我尝试将flink作业以application mode方式提交到kubernetes上运行。但程序的依赖包并不完全存在于local:///opt/flink/usrlib/xxxx.jar中。导致找不到类。
> 在yarn上可以工作，是因为我们用 {color:#ff0000}-C [http://xxxx|http://xxxx/] {color}的方式，让依赖可以被URLClassloader加载。
> 但我发现，当实验提交到kubernetes时，-C只会在 configmap/flink-conf.yaml 中生成一个pipeline.classpaths 配置条目。我们的main函数可以执行，但是在加载外部依赖类的时候提示找不到类。
> 通过阅读源码，*我发现运行用户代码的类加载器实际并没有把 pipeline.classpaths 中的条目加入候选URL*，这导致了无法加载类的情况。从源码中，我也发现，通过将依赖包放在usrlib目录下（默认的userClassPath）可以解决问题。但我们的依赖可能是动态的，不合适一次性打到镜像里面。
> 我提议可以改进这个过程，将pipeline.classpaths也加入到对应的类加载器。这个改动很小，我自己经过测试，可以完美解决问题。
>  
>  
> English translation:
> I'm trying to submit flink job to kubernetes cluster with application mode, but throw ClassNotFoundException when some dependency class is not shipped in kind of local:///opt/flink/usrlib/xxxx.jar.
> This works on yarn, since we use {color:#ff0000}-C [http://xxxx|http://xxxx/]{color} command line style that let dependency class  can be load by URLClassloader.
> But i figure out that not works on kubernetes. When submit to kubernetes cluster, -C is only shipped as item "pipeline.classpaths" in configmap/flink-conf.yaml。
> After read the source code, *i find out that the Classloader launching the "main" entry of user code miss consider adding pipeline.classpaths into candidates URLs*. from source code, i also learn that we can ship the dependency jar in the usrlib dir to solve the problem. But that failed for us, we are not _preferred_ to ship dependencies in image at compile time, since dependencies are known dynamically in runtime
> I proposed to improve the process, let the Classloader consider usrlib as well as pipeline.classpaths, this is a quite little change. I test the solution and it works quite well
>  
>  



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