We're seeing this occasionally. Granted, this was caused by a wrinkle in the Solr schema but this bubbled up all the way in Spark and caused job failures.
I just checked and SolrException class is actually in the consumer job jar we use. Is there any reason why Spark cannot find the SolrException class? 15/09/29 15:41:58 WARN ThrowableSerializationWrapper: Task exception could not be deserialized java.lang.ClassNotFoundException: org.apache.solr.common.SolrException at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:348) at org.apache.spark.serializer.JavaDeserializationStream$$anon$1.resolveClass(JavaSerializer.scala:67) at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1613) at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1518) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1774) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at org.apache.spark.ThrowableSerializationWrapper.readObject(TaskEndReason.scala:163) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1900) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:72) at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:98) at org.apache.spark.scheduler.TaskResultGetter$$anon$3$$anonfun$run$2.apply$mcV$sp(TaskResultGetter.scala:108) at org.apache.spark.scheduler.TaskResultGetter$$anon$3$$anonfun$run$2.apply(TaskResultGetter.scala:105) at org.apache.spark.scheduler.TaskResultGetter$$anon$3$$anonfun$run$2.apply(TaskResultGetter.scala:105) at org.apache.spark.util.Utils$.logUncaughtExceptions(Utils.scala:1699) at org.apache.spark.scheduler.TaskResultGetter$$anon$3.run(TaskResultGetter.scala:105) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)
