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From kedar mhaswade <kedar.mhasw...@gmail.com>
Subject Re: Class loading issues when using Remote Execution Environment
Date Thu, 26 Apr 2018 16:42:32 GMT
Thanks Chesnay for your incredible help!

I will try out the suggestions again. A few questions:
- What version of Flink are you trying with? I have had issues when I
placed the gradoop-demo-shaded.jar in the lib folder on Flink installation
(1.4 even refused to start!).
- Are there other config changes (flink-conf.yaml) that you made in your
- Is org.apache.flink.api.common.io.FileOutputFormat a good alternative to
LocalCollectionOutputFormat, or should I use HadoopOutputFormatCommonBase
(I do want to run the cluster on YARN later; at the moment I am trying on a
standalone cluster).
- Do you think it is better to use jarFiles argument on
createRemoteEnvironment (which deploys the JAR only for this job and not
mess with the entire Flink cluster) a better option than placing the JAR(s)
in the lib folder?

Thanks again,

On Thu, Apr 26, 2018 at 3:14 AM, Chesnay Schepler <chesnay@apache.org>

> Small update:
> I could reproduce your problems locally when submitting the fat-jar.
> I could get the job to run after placing the gradoop-demo-shaded.jar into
> the lib folder.
> I have not tried yet placing only the gradoop jars into lib (but my guess
> is you missed a gradoop jar)
> Note that the job fails to run since you use "LocalCollectionOutputFormat"
> which can only be used for local execution, i.e. when the job submission
> and execution happen in the same JVM.
> On 25.04.2018 14:23, kedar mhaswade wrote:
> Thank you for your response!
> I have not tried the flink run app.jar route because the way the app is
> set up does not allow me to do it. Basically, the app is a web application
> which serves the UI and also submits a Flink job for running Cypher
> queries. It is a proof-of-concept app, but IMO, a very useful one.
> Here's how you can reproduce:
> 1) git clone git@github.com:kedarmhaswade/gradoop_demo.git (this is my
> fork of gradoop_demo)
> 2) cd gradoop_demo
> 3) git checkout dev => dev is the branch where my changes to make gradoop
> work with remote environment go.
> 4) mvn clean package => should bring the gradoop JARs that this app needs;
> these JARs should then be placed in <flink-install>/lib.
> 5) cp ~/.m2/repository/org/gradoop/gradoop-common/0.3.2/gradoop-common-0.3.2.jar
> <flink-install>/lib, cp ~/.m2/repository/org/gradoop/
> gradoop-flink/0.3.2/gradoop-flink-0.3.2.jar <flink-install>/lib,
> cp target/gradoop-demo-0.2.0.jar <flink-install>/lib.
> 6) start the local flink cluster (I have tried with latest
> (built-from-source) 1.6-SNAPSHOT, or 1.4) <flink-install>/bin/start-cluster.sh
> -- note the JM host and port
> 7) <gradoop-demo>/start.sh --jmhost <host> --jmport 6123 (adjust host and
> port per your cluster) => this is now configured to talk to the
> RemoteEnvironment at given JM host and port.
> 8) open a browser at: http://localhost:2342/gradoop/html/cypher.html
> 9) hit the query button => this would throw the exception
> 10) Ctrl C the process in 7 and just restart it as java -cp target/
> classes:target/gradoop-demo-shaded.jar org.gradoop.demo.server.Server =>
> starts LocalEnvironment
> 11) do 9 again and see the results shown nicely in the browser.
> Here is the relevant code:
> 1) Choosing between
> <https://github.com/kedarmhaswade/gradoop_demo/blob/dev/src/main/java/org/gradoop/demo/server/Server.java#L107>
> a Remote or a Local Environment.
> The instructions are correct to my knowledge. Thanks for your willingness
> to try. I have tried everything I can. With different Flink versions, I get
> different results (I have also tried on 1.6-SNAPSHOT with class loading
> config being parent-first, or child-first).
> Regards,
> Kedar
> On Wed, Apr 25, 2018 at 1:08 AM, Chesnay Schepler <chesnay@apache.org>
> wrote:
>> I couldn't spot any error in what you tried to do. Does the
>> job-submission succeed if you submit the jar through the command-line
>> client?
>> Can you share the project, or a minimal reproducing version?
>> On 25.04.2018 00:41, kedar mhaswade wrote:
>> I am trying to get gradoop_demo
>> <https://github.com/dbs-leipzig/gradoop_demo> (a gradoop based graph
>> visualization app) working on Flink with *Remote* Execution Environment.
>> This app, which is based on Gradoop, submits a job to the *preconfigured*
>> execution environment, collects the results and sends it to the UI for
>> rendering.
>> When the execution environment is configured to be a LocalEnvironment
>> <https://ci.apache.org/projects/flink/flink-docs-stable/api/java/org/apache/flink/api/java/LocalEnvironment.html>,
>> everything works fine. But when I start a cluster (using <
>> flink-install-path>/bin/start-cluster.sh), get the Job Manager endpoint
>> (e.g. localhost:6123) and configure a RemoteEnvironment
>> <https://ci.apache.org/projects/flink/flink-docs-stable/api/java/org/apache/flink/api/java/ExecutionEnvironment.html#createRemoteEnvironment-java.lang.String-int-org.apache.flink.configuration.Configuration-java.lang.String...->
>> use that environment to run the job, I get exceptions [1].
>> Based on the class loading doc
>> <https://ci.apache.org/projects/flink/flink-docs-master/monitoring/debugging_classloading.html>,
>> I copied the gradoop classes (gradoop-flink-0.3.3-SNAPSHOT.
>> jar, gradoop-common-0.3.3-SNAPSHOT.jar) to the <flink-install-path>/lib
>> folder (hoping that that way those classes will be available to all the
>> executors in the cluster). I have ensured that the class that Flink fails
>> to load is in fact available in the Gradoop jars that I copied to the
>> /lib folder.
>> I have tried using the RemoteEnvironment method with jarFiles argument
>> where the passed JAR file is a fat jar containing everything (in which case
>> there is no Gradoop JAR file in /lib folder).
>> So, my questions are:
>> 1) How can I use RemoteEnvironment?
>> 2) Is there any other way of doing this *programmatically? *(That means
>> I can't do flink run since I am interested in the job execution result as a
>> blocking call -- which means ideally I don't want to use the submit RESTful
>> API as well). I just want RemoteEnvironment to work as well as
>> LocalEnvironment.
>> Regards,
>> Kedar
>> [1]
>> 2018-04-24 15:16:02,823 ERROR org.apache.flink.runtime.jobmanager.JobManager
>>               - Failed to submit job 0c987c8704f8b7eb4d7d38efcb3d708d
>> (Flink Java Job at Tue Apr 24 15:15:59 PDT 2018)
>> java.lang.NoClassDefFoundError: Could not initialize class
>> *org.gradoop.common.model.impl.id.GradoopId*
>>   at java.io.ObjectStreamClass.hasStaticInitializer(Native Method)
>>   at java.io.ObjectStreamClass.computeDefaultSUID(ObjectStreamCla
>> ss.java:1887)
>>   at java.io.ObjectStreamClass.access$100(ObjectStreamClass.java:79)
>>   at java.io.ObjectStreamClass$1.run(ObjectStreamClass.java:263)
>>   at java.io.ObjectStreamClass$1.run(ObjectStreamClass.java:261)
>>   at java.security.AccessController.doPrivileged(Native Method)
>>   at java.io.ObjectStreamClass.getSerialVersionUID(ObjectStreamCl
>> ass.java:260)
>>   at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:682)
>>   at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream
>> .java:1876)
>>   at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1745)
>>   at java.io.ObjectInputStream.readClass(ObjectInputStream.java:1710)
>>   at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1550)
>>   at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)
>>   at java.util.HashSet.readObject(HashSet.java:341)
>>   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>>   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAcce
>> ssorImpl.java:62)
>>   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMe
>> thodAccessorImpl.java:43)
>>   at java.lang.reflect.Method.invoke(Method.java:498)
>>   at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass
>> .java:1158)
>>   at java.io.ObjectInputStream.readSerialData(ObjectInputStream.
>> java:2169)
>>   at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStre
>> am.java:2060)
>>   at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
>>   at java.io.ObjectInputStream.defaultReadFields(ObjectInputStrea
>> m.java:2278)
>>   at java.io.ObjectInputStream.readSerialData(ObjectInputStream.
>> java:2202)
>>   at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStre
>> am.java:2060)
>>   at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
>>   at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)
>>   at org.apache.flink.util.InstantiationUtil.deserializeObject(In
>> stantiationUtil.java:290)....

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