[jira] [Created] (FLINK-21289) Application mode on kubernetes deployment support run PackagedProgram.main with pipeline.classpaths

["Zhou Parker (Jira)" <ji...@apache.org>]

Zhou Parker created FLINK-21289:
-----------------------------------

             Summary: Application mode on kubernetes deployment support run PackagedProgram.main with pipeline.classpaths
                 Key: FLINK-21289
                 URL: https://issues.apache.org/jira/browse/FLINK-21289
             Project: Flink
          Issue Type: Improvement
          Components: Client / Job Submission, Deployment / Kubernetes
    Affects Versions: 1.12.1, 1.11.2
         Environment: flink: 1.11

kubernetes: 1.15

 
            Reporter: Zhou Parker
         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，可以通过将依赖包放在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。

 

I'm trying to submit flink job to kubernetes cluster with application mode, but throw ClassNotFoundException when 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{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 without consider add 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 failed for me, we are not _preferred_ to ship dependencies in image at compile time, since they are known dynamically in runtime

I proposed improving 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

 

 



--
This message was sent by Atlassian Jira
(v8.3.4#803005)