You are viewing a plain text version of this content. The canonical link for it is here.

Posted to common-issues@hadoop.apache.org by GitBox <gi...@apache.org> on 2022/12/04 10:36:08 UTC

[GitHub] [hadoop] GauthamBanasandra opened a new pull request, #5183: YARN-11386. Fix issue with classpath resolution

GauthamBanasandra opened a new pull request, #5183:
URL: https://github.com/apache/hadoop/pull/5183

### Description of PR
While launching the AM, the client puts the classpath into environment HashMap of the ContainerLaunchContext. To support cross-platform compatibility, some special notations must be used by the client. For example, <CPS> must be used as the classpath separator instead of ";" (Windows) or ":" (Linux). The NM would resolve all the <CPS> using the appropriate path separator according to the OS platform, prior to launching the container. In addition to this, the NM is also expected to expand and resolve all of the wildcard ( * ) occurrences in the classpath before launching the container, since the JVM doesn't understand the wildcard charater.

The issue we see here is, neither <CPS> resolution nor wildcard expansion is happening.

I tested this from Spark. To run a Spark application on YARN, one needs to set the spark.yarn.jars config to point to the location where Spark jars are present. NM would then add these jars to the classpath before launching the Spark AM container. The resolution didn't happen -

```
Manifest-Version:
1.0
Class-Path:
file:/D:/tmp/hadoop-Gautham/nm-local-dir/usercache/Gautham/appcache/application_1670138957874_0001/container_1670138957874_0001_01_000001/%7B%7BPWD%7D%7D%3CCPS%3E%7B%7BPWD%7D%7D/__spark_conf__%3CCPS%3E%7B%7BPWD%7D%7D/__spark_libs__/*%3CCPS%3E/D:/projects/github/apache/spark/jars/*%3CCPS%3E%7B%7BPWD%7D%7D/__spark_conf__/__hadoop_conf__
file:/D:/tmp/hadoop-Gautham/nm-local-dir/usercache/Gautham/appcache/application_1670138957874_0001/container_1670138957874_0001_01_000001/__spark_conf__/
file:/D:/tmp/hadoop-Gautham/nm-local-dir/usercache/Gautham/appcache/application_1670138957874_0001/container_1670138957874_0001_01_000001/__app__.jar
```

Note that `%3CCPS%3E` in the above code block should've been replaced by ";" or ":" as part of classpath resolution. Since this didn't happen, NM failed to launch the Spark AM container -

```
Could not find or load main class org.apache.spark.deploy.yarn.ApplicationMaster
```

### How was this patch tested?
I tested locally by submitting a Spark job and ensured that it ran successfully.

### For code changes:

- [x] Does the title or this PR starts with the corresponding JIRA issue id (e.g. 'HADOOP-17799. Your PR title ...')?
- [ ] Object storage: have the integration tests been executed and the endpoint declared according to the connector-specific documentation?
- [ ] If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under [ASF 2.0](http://www.apache.org/legal/resolved.html#category-a)?
- [ ] If applicable, have you updated the `LICENSE`, `LICENSE-binary`, `NOTICE-binary` files?

--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: common-issues-unsubscribe@hadoop.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org

---------------------------------------------------------------------
To unsubscribe, e-mail: common-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: common-issues-help@hadoop.apache.org