How to spark-submit to ZooKeeper-managed Mesos cluster (gives java.net.UnknownHostException: zk for mesos://zk:// master URL)? - apache-spark

Question

I'm running Spark 2.0.2 and Mesos 0.28.2.
I'm attempting to submit an application to Spark, using a ZooKeeper-managed Mesos cluster as the master:
$SPARK_HOME/bin/spark-submit --verbose \
--conf spark.mesos.executor.docker.image=$DOCKER_IMAGE \
--conf spark.mesos.executor.home=$SPARK_HOME \
--conf spark.executorEnv.MESOS_NATIVE_JAVA_LIBRARY=/usr/lib/libmesos.so \
--deploy-mode cluster \
--master mesos://zk://<ip 1>:2181,<ip 2>:2181,<ip 3>:2181/mesos \
--class $APP_MAIN_CLASS \
file://$APP_JAR_PATH
(<ip 1>, <ip 2>, and <ip 3> are IPv4 addresses in the 10.0.0.0/8 block)
According to the documentation, I seem to have the right format for the master:
The Master URLs for Mesos are in the form mesos://host:5050 for a single-master Mesos cluster, or mesos://zk://host1:2181,host2:2181,host3:2181/mesos for a multi-master Mesos cluster using ZooKeeper.
However, it appears that Spark is reading the mesos://zk://... string then attempting to connect to zk:
17/04/07 20:10:06 INFO RestSubmissionClient: Submitting a request to launch an application in mesos://zk://<ip 1>:2181,<ip 2>:2181,<ip 3>:2181/mesos.
Exception in thread "main" java.net.UnknownHostException: zk
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:184)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at sun.net.NetworkClient.doConnect(NetworkClient.java:180)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:432)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:527)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:211)
at sun.net.www.http.HttpClient.New(HttpClient.java:308)
at sun.net.www.http.HttpClient.New(HttpClient.java:326)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1202)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1138)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1032)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:966)
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream0(HttpURLConnection.java:1316)
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1291)
at org.apache.spark.deploy.rest.RestSubmissionClient.org$apache$spark$deploy$rest$RestSubmissionClient$$postJson(RestSubmissionClient.scala:214)
at org.apache.spark.deploy.rest.RestSubmissionClient$$anonfun$createSubmission$3.apply(RestSubmissionClient.scala:89)
at org.apache.spark.deploy.rest.RestSubmissionClient$$anonfun$createSubmission$3.apply(RestSubmissionClient.scala:85)
at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.scala:733)
at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186)
at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:732)
at org.apache.spark.deploy.rest.RestSubmissionClient.createSubmission(RestSubmissionClient.scala:85)
at org.apache.spark.deploy.rest.RestSubmissionClient$.run(RestSubmissionClient.scala:417)
at org.apache.spark.deploy.rest.RestSubmissionClient$.main(RestSubmissionClient.scala:430)
at org.apache.spark.deploy.rest.RestSubmissionClient.main(RestSubmissionClient.scala)
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:498)
at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:736)
at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:185)
at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:210)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:124)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
How do I get Spark to recognize that it should be using the three ZooKeeper nodes rather than trying to connect to a non-existent zk host?

Answer 1

tl;dr It won't work unless you either change --deploy-mode to client or use a master URL with a single Mesos host, e.g. mesos://host:port.
The following line gives the hint where to find the relevant code.
17/04/07 20:10:06 INFO RestSubmissionClient: Submitting a request to launch an application in mesos://zk://:2181,:2181,:2181/mesos.
It looks that the message is only printed out for --deploy-mode cluster with Spark Standalone and Apache Mesos. Change it to the default client and the deployment path will change and hopefully accept the master URL.
See yourself the code that's responsible for the cluster deployment -- RestSubmissionClient.
Here RestSubmissionClient says:
private val supportedMasterPrefixes = Seq("spark://", "mesos://")
which proves mesos:// URLs are covered, but here you see the following:
private val masters: Array[String] = if (master.startsWith("spark://")) {
Utils.parseStandaloneMasterUrls(master)
} else {
Array(master)
}
that is printed out here as the above INFO message that shows the URL can only be a single Mesos master.