Is FAIR available for Spark Standalone cluster mode? - scala

I'm having 2 node cluster with spark standalone cluster manager. I'm triggering more than one job using same sc with Scala multi threading.What I found is my jobs are scheduled one after another because of FIFO nature so I tried to use FAIR scheduling
conf.set("spark.scheduler.mode", "FAIR")
conf.set("spark.scheduler.allocation.file", sys.env("SPARK_HOME") + "/conf/fairscheduler.xml")
val job1 = Future {
val job = new Job1()
job.run()
}
val job2 =Future {
val job = new Job2()
job.run()
}
class Job1{
def run()
sc.setLocalProperty("spark.scheduler.pool", "mypool1")
}
}
class Job2{
def run()
sc.setLocalProperty("spark.scheduler.pool", "mypool2")
}
}
<pool name="mypool1">
<schedulingMode>FAIR</schedulingMode>
<weight>1</weight>
<minShare>2</minShare>
</pool>
<pool name="mypool2">
<schedulingMode>FAIR</schedulingMode>
<weight>1</weight>
<minShare>2</minShare>
</pool>
Job1 and Job2 will be triggered from an launcher class. Even after setting these properties, my jobs are handled in FIFO.
Is FAIR available for Spark Standalone cluster mode?Is there a page
where it's described in more details? I can't seem to find much about
FAIR and Standalone in Job Scheduling.I'm following this SOF question.am I missing anything here ?

I don't think standalone is the problem. You described creating only one pool, so I think your problem is that you need at least one more pool and assign each job to a different pool.
FAIR scheduling is done across pools, anything within the same pool will run in FIFO mode anyway.
This is based on the documentation here:
https://spark.apache.org/docs/latest/job-scheduling.html#default-behavior-of-pools

Related

Flink job cant use savepoint in a batch job

Let me start in a generic fashion to see if I somehow missed some concepts: I have a streaming flink job from which I created a savepoint. Simplified version of this job looks like this
Pseduo-Code:
val flink = StreamExecutionEnvironment.getExecutionEnvironment
val stream = if (batchMode) {
flink.readFile(path)
}
else {
flink.addKafkaSource(topicName)
}
stream.keyBy(key)
stream.process(new ProcessorWithKeyedState())
CassandraSink.addSink(stream)
This works fine as long as I run the job without a savepoint. If I start the job from a savepoint I get an exception which looks like this
Caused by: java.lang.UnsupportedOperationException: Checkpoints are not supported in a single key state backend
at org.apache.flink.streaming.api.operators.sorted.state.NonCheckpointingStorageAccess.resolveCheckpoint(NonCheckpointingStorageAccess.java:43)
at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.restoreSavepoint(CheckpointCoordinator.java:1623)
at org.apache.flink.runtime.scheduler.SchedulerBase.tryRestoreExecutionGraphFromSavepoint(SchedulerBase.java:362)
at org.apache.flink.runtime.scheduler.SchedulerBase.createAndRestoreExecutionGraph(SchedulerBase.java:292)
at org.apache.flink.runtime.scheduler.SchedulerBase.<init>(SchedulerBase.java:249)
I could work around this if I set the option:
execution.batch-state-backend.enabled: false
but this eventually results in another error:
Caused by: java.lang.IllegalArgumentException: The fraction of memory to allocate should not be 0. Please make sure that all types of managed memory consumers contained in the job are configured with a non-negative weight via `taskmanager.memory.managed.consumer-weights`.
at org.apache.flink.util.Preconditions.checkArgument(Preconditions.java:160)
at org.apache.flink.runtime.memory.MemoryManager.validateFraction(MemoryManager.java:673)
at org.apache.flink.runtime.memory.MemoryManager.computeMemorySize(MemoryManager.java:653)
at org.apache.flink.runtime.memory.MemoryManager.getSharedMemoryResourceForManagedMemory(MemoryManager.java:526)
Of course I tried to set the config key taskmanager.memory.managed.consumer-weights (used DATAPROC:70,PYTHON:30) but this doesn't seems to have any effects.
So I wonder if I have a conceptual error and can't reuse savepoints from a streaming job in a batch job or if I simply have a problem in my configuration. Any hints?
After a hint from the flink user-group it turned out that it is NOT possible to reuse a savepoint from the streaming job (https://ci.apache.org/projects/flink/flink-docs-master/docs/dev/datastream/execution_mode/#state-backends--state). So instead of running the job as in batch-mode (flink.setRuntimeMode(RuntimeExecutionMode.BATCH)) I just run it in the default execution mode (STREAMING). This has the minor downside that it will run forever and have to be stopped by someone once all data was processed.

Shutdown Hook for spark batch application

I have a spark scala batch application. It commits the run status to mariadb when it completes or fails.
I want to implement an edge case when the application is killed by say "yarn application -kill [appid]", I want to update the status as failed in mariadb table.
I planned to use "ShutdownHookManager" for the same but I see it is private in spark and the scala sys.ShutdownHookThread does not work as well.
Can somebody guide me on the shutdown hook handling of killing spark batch application. Not much resources on the same.
You can create a custom SparkListener that reacts on the onApplicationEnd event:
class MyListener extends SparkListener {
override def onApplicationEnd(applicationEnd: SparkListenerApplicationEnd): Unit = {
println("Shutting down...")
}
}
This listener can then be added to the SparkContext:
spark.sparkContext.addSparkListener(new MyListener())
When the Spark application terminates, the string Shutting down... is printed on the console.

Checkpoint data corruption in Spark Streaming

I am testing checkpointing and write ahead logs with this basic Spark streaming code below. I am checkpointing into a local directory. After starting and stopping the application a few times (using Ctrl-C) - it would refuse to start, for what looks like some data corruption in the checkpoint directoty. I am getting:
org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 80.0 failed 1 times, most recent failure: Lost task 0.0 in stage 80.0 (TID 17, localhost): com.esotericsoftware.kryo.KryoException: Encountered unregistered class ID: 13994
at com.esotericsoftware.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:137)
at com.esotericsoftware.kryo.Kryo.readClass(Kryo.java:670)
at com.esotericsoftware.kryo.Kryo.readClassAndObject(Kryo.java:781)
at org.apache.spark.serializer.KryoDeserializationStream.readObject(KryoSerializer.scala:229)
at org.apache.spark.serializer.DeserializationStream$$anon$1.getNext(Serializer.scala:169)
at org.apache.spark.util.NextIterator.hasNext(NextIterator.scala:73)
at scala.collection.Iterator$$anon$12.hasNext(Iterator.scala:439)
at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:408)
at org.apache.spark.util.collection.ExternalSorter.insertAll(ExternalSorter.scala:192)
Full code:
import org.apache.hadoop.conf.Configuration
import org.apache.spark._
import org.apache.spark.streaming._
object ProtoDemo {
def createContext(dirName: String) = {
val conf = new SparkConf().setAppName("mything")
conf.set("spark.streaming.receiver.writeAheadLog.enable", "true")
val ssc = new StreamingContext(conf, Seconds(1))
ssc.checkpoint(dirName)
val lines = ssc.socketTextStream("127.0.0.1", 9999)
val words = lines.flatMap(_.split(" "))
val pairs = words.map(word => (word, 1))
val wordCounts = pairs.reduceByKey(_ + _)
val runningCounts = wordCounts.updateStateByKey[Int] {
(values: Seq[Int], oldValue: Option[Int]) =>
val s = values.sum
Some(oldValue.fold(s)(_ + s))
}
// Print the first ten elements of each RDD generated in this DStream to the console
runningCounts.print()
ssc
}
def main(args: Array[String]) = {
val hadoopConf = new Configuration()
val dirName = "/tmp/chkp"
val ssc = StreamingContext.getOrCreate(dirName, () => createContext(dirName), hadoopConf)
ssc.start()
ssc.awaitTermination()
}
}
Basically what you are trying to do is a driver failure scenario , for this to work , based on the cluster you are running you have to follow the below instructions to monitor the driver process and relaunch the driver if it fails
Configuring automatic restart of the application driver - To automatically recover from a driver failure, the deployment infrastructure that is used to run the streaming application must monitor the driver process and relaunch the driver if it fails. Different cluster managers have different tools to achieve this.
Spark Standalone - A Spark application driver can be submitted to
run within the Spark Standalone cluster (see cluster deploy
mode), that is, the application driver itself runs on one of the
worker nodes. Furthermore, the Standalone cluster manager can be
instructed to supervise the driver, and relaunch it if the driver
fails either due to non-zero exit code, or due to failure of the
node running the driver. See cluster mode and supervise in the Spark
Standalone guide for more details.
YARN - Yarn supports a similar mechanism for automatically restarting an application. Please refer to YARN documentation for
more details.
Mesos - Marathon has been used to achieve this with Mesos.
You need to configure write ahead logs as below ,there are special instructions for S3 which you need to follow.
While using S3 (or any file system that does not support flushing) for write ahead logs, please remember to enable
spark.streaming.driver.writeAheadLog.closeFileAfterWrite
spark.streaming.receiver.writeAheadLog.closeFileAfterWrite.
See Spark Streaming Configuration for more details.
The issue looks rather Kryo Serializer issue than checkpoint corruption.
At code example (including GitHub project), Kryo Serialization is not configured.
Since it is not configured KryoException exception could not happen.
When using "write ahead logs", and restoring from a directory, all Spark config is getting from there.
At your example, createContext method does not call when starting from the checkpoint.
I assume the issue is another application were tested before with the same checkpoint directory, where Kryo Serializer where configured.
And current application fails to be restored from that checkpoint.

Simple Spark program eats all resources

I have server with running in it Spark master and slave. Spark was built manually with next flags:
build/mvn -Pyarn -Phadoop-2.6 -Dscala-2.11 -DskipTests clean package
I'm trying to execute next simple program remotely:
def main(args: Array[String]) {
val conf = new SparkConf().setAppName("testApp").setMaster("spark://sparkserver:7077")
val sc = new SparkContext(conf)
println(sc.parallelize(Array(1,2,3)).reduce((a, b) => a + b))
}
Spark dependency:
"org.apache.spark" %% "spark-core" % "1.6.1"
Log on program executing:
16/04/12 18:45:46 WARN TaskSchedulerImpl: Initial job has not accepted any resources; check your cluster UI to ensure that workers are registered and have sufficient resources
My cluster WebUI:
Why so simple application uses all availiable resources?
P.S. Also I noticed what if I allocate more memory for my app (10 gb e.g.) next logs appear many times:
16/04/12 19:23:40 INFO AppClient$ClientEndpoint: Executor updated: app-20160412182336-0008/208 is now RUNNING
16/04/12 19:23:40 INFO AppClient$ClientEndpoint: Executor updated: app-20160412182336-0008/208 is now EXITED (Command exited with code 1)
I think that reason in connection between master and slave. How I set up master and slave(on the same machine):
sbin/start-master.sh
sbin/start-slave.sh spark://sparkserver:7077
P.P.S. When I'm connecting to spark master with spark-shell all is good:
spark-shell --master spark://sparkserver:7077
By default, yarn will allocate all "available" ressources if the yarn dynamic ressource allocation is set to true and your job still have queued tasks. You can also look for your yarn configuration, namely the number of executor and the memory allocated to each one and tune in function of your need.
in file:spark-default.xml ------->setting :spark.cores.max=4
It was a driver issue. Driver (My scala app) was ran on my local computer. And workers have no access to it. As result all resources were eaten by attempts to reconnect to a driver.

Akka test how to use multiple Executioncontexts

my actor runs on default akka dispatcher, which then calls a method which returns a future. I have configured different executioncontexts for all futures to run (since they are blocking(due to db calls) and to keep actors dispatcher dedicated to non blocking actors only. Wondering if this code can be tested (continue using two execution contexts etc) using Akka Testkit? If so what would be the way to configure a test so Actor runs on default dispatcher and futures can find "custom-dispatcher" as well for them to run? Obviously currently test throws following.
Caused by: akka.ConfigurationException: Dispatcher [custom-dispatcher] not configured
When you create an Akka Testkit's TestActorRef for an Actor it will use PinnedDispatcher except you've specified a different one in Actor's Props and passed that Props when creating the TestActorRef.
The exception "Dispatcher [custom-dispatcher] not configured" may mean that you are using different Akka config for your tests in which no dispatcher with name [custom-dispatcher] configured.
create a file application.conf in your test/resources directory
my-custom-dispatcher {
executor = "thread-pool-executor"
type = PinnedDispatcher
}
then in your test when you create the actor
val boothWorker = system.actorOf(Props(classOf[WorkerTest]))
.withDispatcher("my-custom-dispatcher"))