| /** |
| * 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.hadoop.yarn.server.sharedcachemanager; |
| |
| import java.io.IOException; |
| import java.lang.management.ManagementFactory; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| import org.apache.hadoop.HadoopIllegalArgumentException; |
| import org.apache.hadoop.classification.InterfaceAudience.Private; |
| import org.apache.hadoop.classification.InterfaceStability.Evolving; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.FSDataOutputStream; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.service.CompositeService; |
| import org.apache.hadoop.util.concurrent.HadoopExecutors; |
| import org.apache.hadoop.yarn.conf.YarnConfiguration; |
| import org.apache.hadoop.yarn.exceptions.YarnException; |
| import org.apache.hadoop.yarn.server.sharedcachemanager.metrics.CleanerMetrics; |
| import org.apache.hadoop.yarn.server.sharedcachemanager.store.SCMStore; |
| |
| import com.google.common.util.concurrent.ThreadFactoryBuilder; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * The cleaner service that maintains the shared cache area, and cleans up stale |
| * entries on a regular basis. |
| */ |
| @Private |
| @Evolving |
| public class CleanerService extends CompositeService { |
| /** |
| * The name of the global cleaner lock that the cleaner creates to indicate |
| * that a cleaning process is in progress. |
| */ |
| public static final String GLOBAL_CLEANER_PID = ".cleaner_pid"; |
| |
| private static final Logger LOG = |
| LoggerFactory.getLogger(CleanerService.class); |
| |
| private Configuration conf; |
| private CleanerMetrics metrics; |
| private ScheduledExecutorService scheduledExecutor; |
| private final SCMStore store; |
| private final Lock cleanerTaskLock; |
| |
| public CleanerService(SCMStore store) { |
| super("CleanerService"); |
| this.store = store; |
| this.cleanerTaskLock = new ReentrantLock(); |
| } |
| |
| @Override |
| protected void serviceInit(Configuration conf) throws Exception { |
| this.conf = conf; |
| |
| // create scheduler executor service that services the cleaner tasks |
| // use 2 threads to accommodate the on-demand tasks and reduce the chance of |
| // back-to-back runs |
| ThreadFactory tf = |
| new ThreadFactoryBuilder().setNameFormat("Shared cache cleaner").build(); |
| scheduledExecutor = HadoopExecutors.newScheduledThreadPool(2, tf); |
| super.serviceInit(conf); |
| } |
| |
| @Override |
| protected void serviceStart() throws Exception { |
| if (!writeGlobalCleanerPidFile()) { |
| throw new YarnException("The global cleaner pid file already exists! " + |
| "It appears there is another CleanerService running in the cluster"); |
| } |
| |
| this.metrics = CleanerMetrics.getInstance(); |
| |
| // Start dependent services (i.e. AppChecker) |
| super.serviceStart(); |
| |
| Runnable task = |
| CleanerTask.create(conf, store, metrics, cleanerTaskLock); |
| long periodInMinutes = getPeriod(conf); |
| scheduledExecutor.scheduleAtFixedRate(task, getInitialDelay(conf), |
| periodInMinutes, TimeUnit.MINUTES); |
| LOG.info("Scheduled the shared cache cleaner task to run every " |
| + periodInMinutes + " minutes."); |
| } |
| |
| @Override |
| protected void serviceStop() throws Exception { |
| LOG.info("Shutting down the background thread."); |
| scheduledExecutor.shutdownNow(); |
| try { |
| if (scheduledExecutor.awaitTermination(10, TimeUnit.SECONDS)) { |
| LOG.info("The background thread stopped."); |
| } else { |
| LOG.warn("Gave up waiting for the cleaner task to shutdown."); |
| } |
| } catch (InterruptedException e) { |
| LOG.warn("The cleaner service was interrupted while shutting down the task.", |
| e); |
| } |
| |
| removeGlobalCleanerPidFile(); |
| |
| super.serviceStop(); |
| } |
| |
| /** |
| * Execute an on-demand cleaner task. |
| */ |
| protected void runCleanerTask() { |
| Runnable task = |
| CleanerTask.create(conf, store, metrics, cleanerTaskLock); |
| // this is a non-blocking call (it simply submits the task to the executor |
| // queue and returns) |
| this.scheduledExecutor.execute(task); |
| } |
| |
| /** |
| * To ensure there are not multiple instances of the SCM running on a given |
| * cluster, a global pid file is used. This file contains the hostname of the |
| * machine that owns the pid file. |
| * |
| * @return true if the pid file was written, false otherwise |
| * @throws YarnException |
| */ |
| private boolean writeGlobalCleanerPidFile() throws YarnException { |
| String root = |
| conf.get(YarnConfiguration.SHARED_CACHE_ROOT, |
| YarnConfiguration.DEFAULT_SHARED_CACHE_ROOT); |
| Path pidPath = new Path(root, GLOBAL_CLEANER_PID); |
| try { |
| FileSystem fs = FileSystem.get(this.conf); |
| |
| if (fs.exists(pidPath)) { |
| return false; |
| } |
| |
| FSDataOutputStream os = fs.create(pidPath, false); |
| // write the hostname and the process id in the global cleaner pid file |
| final String ID = ManagementFactory.getRuntimeMXBean().getName(); |
| os.writeUTF(ID); |
| os.close(); |
| // add it to the delete-on-exit to ensure it gets deleted when the JVM |
| // exits |
| fs.deleteOnExit(pidPath); |
| } catch (IOException e) { |
| throw new YarnException(e); |
| } |
| LOG.info("Created the global cleaner pid file at " + pidPath.toString()); |
| return true; |
| } |
| |
| private void removeGlobalCleanerPidFile() { |
| try { |
| FileSystem fs = FileSystem.get(this.conf); |
| String root = |
| conf.get(YarnConfiguration.SHARED_CACHE_ROOT, |
| YarnConfiguration.DEFAULT_SHARED_CACHE_ROOT); |
| |
| Path pidPath = new Path(root, GLOBAL_CLEANER_PID); |
| |
| |
| fs.delete(pidPath, false); |
| LOG.info("Removed the global cleaner pid file at " + pidPath.toString()); |
| } catch (IOException e) { |
| LOG.error( |
| "Unable to remove the global cleaner pid file! The file may need " |
| + "to be removed manually.", e); |
| } |
| } |
| |
| private static int getInitialDelay(Configuration conf) { |
| int initialDelayInMinutes = |
| conf.getInt(YarnConfiguration.SCM_CLEANER_INITIAL_DELAY_MINS, |
| YarnConfiguration.DEFAULT_SCM_CLEANER_INITIAL_DELAY_MINS); |
| // negative value is invalid; use the default |
| if (initialDelayInMinutes < 0) { |
| throw new HadoopIllegalArgumentException("Negative initial delay value: " |
| + initialDelayInMinutes |
| + ". The initial delay must be greater than zero."); |
| } |
| return initialDelayInMinutes; |
| } |
| |
| private static int getPeriod(Configuration conf) { |
| int periodInMinutes = |
| conf.getInt(YarnConfiguration.SCM_CLEANER_PERIOD_MINS, |
| YarnConfiguration.DEFAULT_SCM_CLEANER_PERIOD_MINS); |
| // non-positive value is invalid; use the default |
| if (periodInMinutes <= 0) { |
| throw new HadoopIllegalArgumentException("Non-positive period value: " |
| + periodInMinutes |
| + ". The cleaner period must be greater than or equal to zero."); |
| } |
| return periodInMinutes; |
| } |
| } |