SaurabhChawla100 commented on a change in pull request #27636: [SPARK-30873][CORE][YARN]Handling Node Decommissioning for Yarn cluster manger in Spark URL: https://github.com/apache/spark/pull/27636#discussion_r392686355
########## File path: core/src/main/scala/org/apache/spark/scheduler/DecommissionTracker.scala ########## @@ -0,0 +1,405 @@ +/* + * 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 + +import java.text.SimpleDateFormat +import java.util.concurrent.TimeUnit +import java.util.concurrent.atomic.{AtomicBoolean, AtomicInteger} + +import scala.collection.mutable.HashMap + +import org.apache.spark.{ExecutorAllocationClient, SparkConf, SparkContext} +import org.apache.spark.annotation.DeveloperApi +import org.apache.spark.internal.Logging +import org.apache.spark.internal.config +import org.apache.spark.util.{Clock, SystemClock, ThreadUtils, Utils} + +/** + * DecommissionTracker tracks the list of decommissioned nodes. + * This decommission trackers maintains the decommissioned nodes state. + * Decommission tracker schedules the executor decommission and shuffle + * decommission for that node. + */ +private[scheduler] class DecommissionTracker ( + conf: SparkConf, + executorAllocClient: Option[ExecutorAllocationClient], + dagScheduler: Option[DAGScheduler], + clock: Clock = new SystemClock()) extends Logging { + + def this(sc: SparkContext, + client: Option[ExecutorAllocationClient], + dagScheduler: Option[DAGScheduler]) = { + this(sc.conf, client, dagScheduler) + } + + // Decommission thread of node decommissioning!! + private val decommissionThread = + ThreadUtils.newDaemonThreadPoolScheduledExecutor("node-decommissioning-thread", 20) + + // Contains workers hostname which are decommissioning. Added when spot-loss or + // graceful decommissioning event arrives from the AM. And is removed when the + // last node (identified by nodeId) is running again. + private val decommissionHostnameMap = new HashMap[String, NodeDecommissionInfo] + + private val minDecommissionTime = + conf.get(config.GRACEFUL_DECOMMISSION_MIN_TERMINATION_TIME_IN_SEC) + + private val executorDecommissionLeasePct = + conf.get(config.GRACEFUL_DECOMMISSION_EXECUTOR_LEASETIME_PCT) + + private val shuffleDataDecommissionLeasePct = + conf.get(config.GRACEFUL_DECOMMISSION_SHUFFLEDATA_LEASETIME_PCT) + + /* + * Is the node decommissioned i.e from driver point of + * view the node is considered decommissioned. + */ + def isNodeDecommissioned(hostname: String): Boolean = synchronized { + decommissionHostnameMap.get(hostname) match { + case None => false + case Some(info) => + return info.state == NodeDecommissionState.SHUFFLEDATA_DECOMMISSIONED || + info.state == NodeDecommissionState.TERMINATED + } + } + + /* + * Is the node decommissioning i.e from driver point of + * view the node is candidate for decommissioning. + * Not necessarily decommissioned or terminated + */ + def isNodeDecommissioning(hostname: String): Boolean = synchronized { + decommissionHostnameMap.contains(hostname) + } + + /** + * visible only for Unit Test + */ + def getDecommissionedNodeState(hostname: + String): Option[NodeDecommissionState.Value] = synchronized { + decommissionHostnameMap.get(hostname) match { + case Some(info) => Some(info.state) + case _ => None + } + } + + def addNodeToDecommission(hostname: String, terminationTimeMs: Long, + reason: NodeDecommissionReason): Unit = synchronized { + + val df: SimpleDateFormat = new SimpleDateFormat("YY/MM/dd HH:mm:ss") + val tDateTime = df.format(terminationTimeMs) + val curTimeMs = clock.getTimeMillis() + + if (terminationTimeMs <= curTimeMs) { + // Ignoring the decommission request if termination + // time is less than or same as the current time + logWarning(s"Ignoring decommissioning request for host $hostname as" + + s" terminationTimeMs ${terminationTimeMs} is less" + + s" than current time ${curTimeMs}") + return + } + + // Override decommissionHostnameMap in case termination time is less than + // existing the terminationTime in decommissionHostnameMap. + if (decommissionHostnameMap.contains(hostname)) { + val nodeDecommissionInfo = decommissionHostnameMap(hostname) + // There will be no duplicate entry of terminationTimeMs in decommissionHostnameMap + // since the terminationTime is updated only when it is less than the existing termination + // time in decommissionHostnameMap + if (decommissionHostnameMap(hostname).terminationTime <= terminationTimeMs) { + logDebug( + s"""Ignoring decommissioning """ + + s""" request : {"node":"$hostname","reason":"${reason.message}",terminationTime"""" + + s""":"$tDateTime"} current : {"node":"$hostname",$nodeDecommissionInfo}""") + return + } else { + logInfo(s"Updating the termination time to :${terminationTimeMs} in " + + s"decommission tracker for the hostname ${hostname}") + } + } + + val delay = terminationTimeMs - curTimeMs + + var executorDecommissionTimeMs = terminationTimeMs + var shuffleDataDecommissionTimeMs = terminationTimeMs + + // if delay is less than a minDecommissionTime than decommission immediately + if (terminationTimeMs - curTimeMs < minDecommissionTime * 1000) { + executorDecommissionTimeMs = curTimeMs + // Added the delay of 1 second in case of delay is less than a minute + // Since we want executor to be decommissioned first + // than after that shuffleDataDecommission + shuffleDataDecommissionTimeMs = curTimeMs + 1000 Review comment: This is the life cycle of the nodes which is decommissioned DECOMMISSIONING -> EXECUTOR_DECOMMISSIONED -> SHUFFLEDATA_DECOMMISSIONED -> TERMINATED. **Now the query is what happen if SHUFFLEDATA_DECOMMISSIONED happens before or at same time of the EXECUTOR_DECOMMISSIONED** - If we make SHUFFLEDATA_DECOMMISSIONED before the EXECUTOR_DECOMMISSIONED than there is a chance that some of the task will erred out due to fetch failed exception since we have already done SHUFFLEDATA_DECOMMISSIONED here. Also I have explained this here in this comment https://github.com/apache/spark/pull/27636#issuecomment-593338415 ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
