Correct way to create Spark Fat Jar using SBT

I need a Fat Jar with Spark because I am creating a custom node for Knime. This is basically a self-contained jar made inside Knime and I believe the Fat Jar is the only way to spawn a local Spark Job. We will eventually continue submitting the job to the remote cluster, but now I need it to appear this way.

However, I made a Fat Jar using this: https://github.com/sbt/sbt-assembly

I made an empty sbt project, included Spark-core in dependencies, and built a Jar. I added it to the manifest of my custom Knime node and tried to create a simple job (pararellize collection, collect it and print it). It starts up, but I get this error:

Missing config setting for key 'akka.version'

I have no idea how to solve it.

Edit: this is my build.sbt

name := "SparkFatJar"

version := "1.0"

scalaVersion := "2.11.6"

libraryDependencies ++= Seq(
  "org.apache.spark" %% "spark-core" % "1.3.0"
)


libraryDependencies +=  "com.typesafe.akka" %% "akka-actor" % "2.3.8"

assemblyJarName in assembly := "SparkFatJar.jar"

assemblyMergeStrategy in assembly := {
  case PathList("META-INF", xs @ _*) => MergeStrategy.discard
  case x => MergeStrategy.first
}

      

        
        
        
      

    

I found this mergestrategy for Spark somewhere on the internet, but I can't find the source right now.