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From Dmitriy Lyubimov <>
Subject Re: Dependency Versions
Date Fri, 16 Aug 2013 05:06:54 GMT
I don't know if you can (other than trying to rebuild spark with
_your_ version of netty, nothing really comes to mind) but netty
conflict is a notorious problem (not spark specific at all). Spark
uses akka which uses netty and even if you successfully override netty
version, my experience is that  akka will stop working (meaning there
will be no successful communication between any spark processes at

The only way I know is to clean out netty from your job and hope it
still will work (e.g. hbase client tugs netty in dependencies but in
reality never uses it so it is ok to just drop it).

On Thu, Aug 15, 2013 at 7:02 PM, Daniel Duckworth <> wrote:
> tl;dr How does Spark decide precedence when loading JARs? Is there a way to
> force Spark executors to draw all dependencies from my fat JAR?
> Hello Spark users,
> Recently, I've written a Spark task that makes use of finagle for making RPC
> calls.  The version of finagle I'm using (6.5.0) makes use of netty
> 3.5.12.Final, while spark 0.7.0 uses netty 3.5.3. I've recently toyed with
> my Maven POM to prefer netty 3.5.12 and can successfully run the task with
> `MASTER=local`, `MASTER=local[8]` and `MASTER=spark://` (when
> I start up a Spark master and worker locally), but my attempts to run
> remotely on EC2 with a standalone Spark cluster have resulted in the
> following NoSuchMethod exceptions on initializing my finagle client,
> INFO  [2013-08-16T00:58:13.572] []
> spark.scheduler.cluster.TaskSetManager: Loss was due to
> java.lang.NoSuchMethodError:
> Executor;I)V
>         at
> com.twitter.finagle.netty3.WorkerPool$.<init>(WorkerPool.scala:12)
>         at com.twitter.finagle.netty3.WorkerPool$.<clinit>(WorkerPool.scala)
>         at
> com.twitter.finagle.netty3.Netty3Transporter$$anon$1.<init>(client.scala:225)
>         at
> com.twitter.finagle.netty3.Netty3Transporter$.<init>(client.scala:224)
>         at
> com.twitter.finagle.netty3.Netty3Transporter$.<clinit>(client.scala)
> The remote Spark server and workers are using netty 3.5.3, so I suspect that
> their version of netty is overshadowing the one submitted in my fat JAR.
> Is there a way I can force Spark executors to draw dependencies from my fat
> JAR, rather than what they already have?
> Thanks!
> - Daniel Duckworth

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