[SPARK-15046][YARN] Parse value of token renewal interval correctly.

Use the config variable definition both to set and parse the value,
avoiding issues with code expecting the value in a different format.

Tested by running spark-submit with --principal / --keytab.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #13669 from vanzin/SPARK-15046.

core/src/main/scala/org/apache/spark/deploy/SparkHadoopUtil.scala

@@ -41,6 +41,7 @@ import org.apache.hadoop.security.token.delegation.AbstractDelegationTokenIdenti
 import org.apache.spark.{SparkConf, SparkException}
 import org.apache.spark.annotation.DeveloperApi
 import org.apache.spark.internal.Logging
+import org.apache.spark.internal.config._
 import org.apache.spark.util.Utils
 
 /**
@@ -288,8 +289,7 @@ class SparkHadoopUtil extends Logging {
       credentials: Credentials): Long = {
     val now = System.currentTimeMillis()
 
-    val renewalInterval =
-      sparkConf.getLong("spark.yarn.token.renewal.interval", (24 hours).toMillis)
+    val renewalInterval = sparkConf.get(TOKEN_RENEWAL_INTERVAL).get
 
     credentials.getAllTokens.asScala
       .filter(_.getKind == DelegationTokenIdentifier.HDFS_DELEGATION_KIND)

core/src/main/scala/org/apache/spark/internal/config/package.scala

@@ -17,6 +17,8 @@
 
 package org.apache.spark.internal
 
+import java.util.concurrent.TimeUnit
+
 import org.apache.spark.launcher.SparkLauncher
 import org.apache.spark.network.util.ByteUnit
 
@@ -80,6 +82,11 @@ package object config {
     .doc("Name of the Kerberos principal.")
     .stringConf.createOptional
 
+  private[spark] val TOKEN_RENEWAL_INTERVAL = ConfigBuilder("spark.yarn.token.renewal.interval")
+    .internal()
+    .timeConf(TimeUnit.MILLISECONDS)
+    .createOptional
+
   private[spark] val EXECUTOR_INSTANCES = ConfigBuilder("spark.executor.instances")
     .intConf
     .createOptional

yarn/src/main/scala/org/apache/spark/deploy/yarn/config.scala

@@ -243,11 +243,6 @@ package object config {
     .toSequence
     .createWithDefault(Nil)
 
-  private[spark] val TOKEN_RENEWAL_INTERVAL = ConfigBuilder("spark.yarn.token.renewal.interval")
-    .internal()
-    .timeConf(TimeUnit.MILLISECONDS)
-    .createOptional
-
   /* Private configs. */
 
   private[spark] val CREDENTIALS_FILE_PATH = ConfigBuilder("spark.yarn.credentials.file")