LantaoJin commented on a change in pull request #23951: [SPARK-27038][CORE][YARN] Re-implement RackResolver to reduce resolving time URL: https://github.com/apache/spark/pull/23951#discussion_r263653164
########## File path: resource-managers/yarn/src/main/scala/org/apache/spark/scheduler/cluster/YarnRackResolver.scala ########## @@ -0,0 +1,94 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.spark.scheduler.cluster + +import scala.collection.JavaConverters._ +import scala.collection.mutable.ArrayBuffer + +import com.google.common.base.Strings +import org.apache.hadoop.conf.Configuration +import org.apache.hadoop.fs.CommonConfigurationKeysPublic +import org.apache.hadoop.net._ +import org.apache.hadoop.util.ReflectionUtils + +import org.apache.spark.internal.Logging + +/** + * Added in SPARK-27038. Before using the higher Hadoop version which applied YARN-9332, + * we construct [[YarnRackResolver]] instead of [[org.apache.hadoop.yarn.util.RackResolver]] + * to revolve the rack info. + */ +object YarnRackResolver extends Logging { + private var dnsToSwitchMapping: DNSToSwitchMapping = _ + private var initCalled = false + // advisory count of arguments for rack script + private val ADVISORY_MINIMUM_NUMBER_SCRIPT_ARGS = 10000 + + def init(conf: Configuration): Unit = { + if (!initCalled) { + initCalled = true + val dnsToSwitchMappingClass = + conf.getClass(CommonConfigurationKeysPublic.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY, + classOf[ScriptBasedMapping], classOf[DNSToSwitchMapping]) + if (classOf[ScriptBasedMapping].isAssignableFrom(dnsToSwitchMappingClass)) { + val numArgs = conf.getInt(CommonConfigurationKeysPublic.NET_TOPOLOGY_SCRIPT_NUMBER_ARGS_KEY, + CommonConfigurationKeysPublic.NET_TOPOLOGY_SCRIPT_NUMBER_ARGS_DEFAULT) + if (numArgs < ADVISORY_MINIMUM_NUMBER_SCRIPT_ARGS) { Review comment: There isn't any existing "the script" in Hadoop or Spark. This needs to be provided by Hadoop administrator. If it is not set, the default value of DEFAULT_RACK is returned for all node names. But whatever the script looks like, the interface [runResolveCommand](https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/ScriptBasedMapping.java#L220) in `ScriptBasedMapping` is fixed: It accepts a host list and executes several times based on `net.topology.script.number.args` we mentioned above. So I didn't take account of any execution performance of this script. Logging with a higher advisory value is based on the character of Spark jobs comparing to MR job. I will change this logging to INFO and remove the fixed value 10k. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
