nandakumar131 commented on a change in pull request #620: HDDS-1205. Refactor ReplicationManager to handle QUASI_CLOSED contain… URL: https://github.com/apache/hadoop/pull/620#discussion_r266797761
########## File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/ReplicationManager.java ########## @@ -0,0 +1,686 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.hdds.scm.container; + +import com.google.common.annotations.VisibleForTesting; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hdds.protocol.DatanodeDetails; +import org.apache.hadoop.hdds.protocol.proto.HddsProtos.LifeCycleState; +import org.apache.hadoop.hdds.protocol.proto + .StorageContainerDatanodeProtocolProtos.ContainerReplicaProto.State; +import org.apache.hadoop.hdds.scm.ScmConfigKeys; +import org.apache.hadoop.hdds.scm.container.placement.algorithms + .ContainerPlacementPolicy; +import org.apache.hadoop.hdds.scm.events.SCMEvents; +import org.apache.hadoop.hdds.server.events.EventPublisher; +import org.apache.hadoop.ozone.lock.LockManager; +import org.apache.hadoop.ozone.protocol.commands.CloseContainerCommand; +import org.apache.hadoop.ozone.protocol.commands.CommandForDatanode; +import org.apache.hadoop.ozone.protocol.commands.DeleteContainerCommand; +import org.apache.hadoop.ozone.protocol.commands.ReplicateContainerCommand; +import org.apache.hadoop.util.ExitUtil; +import org.apache.hadoop.util.Time; +import org.apache.ratis.util.Preconditions; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.Iterator; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.UUID; +import java.util.concurrent.TimeUnit; +import java.util.function.Predicate; +import java.util.stream.Collectors; + +/** + * Replication Manager (RM) is the one which is responsible for making sure + * that the containers are properly replicated. Replication Manager deals only + * with Quasi Closed / Closed container. + */ +public class ReplicationManager { + + private static final Logger LOG = + LoggerFactory.getLogger(ReplicationManager.class); + + /** + * Reference to the ContainerManager. + */ + private final ContainerManager containerManager; + + /** + * PlacementPolicy which is used to identify where a container + * should be copied. + */ + private final ContainerPlacementPolicy containerPlacement; + + /** + * EventPublisher to fire Replicate and Delete container commands. + */ + private final EventPublisher eventPublisher; + + /** + * Used for locking a container with its ID while processing it. + */ + private final LockManager<ContainerID> lockManager; + + /** + * This is used to track container replication commands which are issued + * by ReplicationManager and not yet complete. + */ + private final Map<ContainerID, List<InflightAction>> inflightReplication; + + /** + * This is used to track container deletion commands which are issued + * by ReplicationManager and not yet complete. + */ + private final Map<ContainerID, List<InflightAction>> inflightDeletion; + + /** + * ReplicationMonitor thread is the one which wakes up at configured + * interval and processes all the containers. + */ + private final Thread replicationMonitor; + + /** + * The frequency in which ReplicationMonitor thread should run. + */ + private final long interval; + + /** + * Timeout for container replication & deletion command issued by + * ReplicationManager. + */ + private final long eventTimeout; + + /** + * Flag used to check if ReplicationMonitor thread is running or not. + */ + private volatile boolean running; + + /** + * Constructs ReplicationManager instance with the given configuration. + * + * @param conf OzoneConfiguration + * @param containerManager ContainerManager + * @param containerPlacement ContainerPlacementPolicy + * @param eventPublisher EventPublisher + */ + public ReplicationManager(final Configuration conf, + final ContainerManager containerManager, + final ContainerPlacementPolicy containerPlacement, + final EventPublisher eventPublisher) { + this.containerManager = containerManager; + this.containerPlacement = containerPlacement; + this.eventPublisher = eventPublisher; + this.lockManager = new LockManager<>(conf); + this.inflightReplication = new HashMap<>(); + this.inflightDeletion = new HashMap<>(); + this.replicationMonitor = new Thread(this::run); + this.replicationMonitor.setName("ReplicationMonitor"); + this.interval = conf.getTimeDuration( + ScmConfigKeys.HDDS_SCM_REPLICATION_THREAD_INTERVAL, + ScmConfigKeys.HDDS_SCM_REPLICATION_THREAD_INTERVAL_DEFAULT, + TimeUnit.MILLISECONDS); + this.eventTimeout = conf.getTimeDuration( + ScmConfigKeys.HDDS_SCM_REPLICATION_EVENT_TIMEOUT, + ScmConfigKeys.HDDS_SCM_REPLICATION_EVENT_TIMEOUT_DEFAULT, + TimeUnit.MILLISECONDS); + this.running = false; + } + + /** + * Starts Replication Monitor thread. + */ + public void start() { + LOG.info("Starting Replication Monitor Thread."); + running = true; + replicationMonitor.start(); + } + + /** + * Process all the containers immediately. + */ + @VisibleForTesting + void processContainersNow() { + containerManager.getContainerIDs() + .parallelStream().forEach(this::processContainer); + } + + /** + * Stops Replication Monitor thread. + */ + public void stop() { + LOG.info("Stopping Replication Monitor Thread."); + running = false; + replicationMonitor.interrupt(); + } + + /** + * ReplicationMonitor thread runnable. This wakes up at configured + * interval and processes all the containers in the system. + */ + private void run() { + try { + while (running) { + try { + final long start = Time.monotonicNow(); + final List<ContainerID> containerIds = + containerManager.getContainerIDs(); + containerIds.parallelStream().forEach(this::processContainer); + LOG.debug("Replication Monitor Thread took {} milliseconds for" + + " processing {} containers.", Time.monotonicNow() - start, + containerIds.size()); + Thread.sleep(interval); + } catch (InterruptedException ex) { + // Wakeup and process the containers. + LOG.debug("Replication Monitor Thread got interrupt exception."); + } + } + } catch (Throwable t) { + // When we get runtime exception, we should terminate SCM. + LOG.error("Exception in Replication Monitor Thread.", t); + ExitUtil.terminate(1, t); + } + } + + /** + * Process the given container. + * + * @param id ContainerID + */ + private void processContainer(ContainerID id) { + lockManager.lock(id); + try { + final ContainerInfo container = containerManager.getContainer(id); + final Set<ContainerReplica> replicas = containerManager + .getContainerReplicas(container.containerID()); + final LifeCycleState state = container.getState(); + + /* + * We don't take any action if the container is in OPEN state. + */ + if (state == LifeCycleState.OPEN) { + return; + } + + /* + * If the container is in CLOSING state, the replicas can either + * be in OPEN or in CLOSING state. In both of this cases + * we have to resend close container command to the datanodes. + */ + if (state == LifeCycleState.CLOSING) { + replicas.forEach(replica -> sendCloseCommand( + container, replica.getDatanodeDetails(), false)); + return; + } + + /* + * Before processing the container we have to reconcile the + * inflightReplication and inflightDeletion actions. + * + * We remove the entry from inflightReplication and inflightDeletion + * list, if the operation is completed or if it has timed out. + */ + updateInflightAction(container, inflightReplication, + action -> replicas.stream() + .anyMatch(r -> r.getDatanodeDetails().equals(action.datanode))); + + updateInflightAction(container, inflightDeletion, + action -> replicas.stream() + .noneMatch(r -> r.getDatanodeDetails().equals(action.datanode))); + + + /* + * If the container is in QUASI_CLOSED state, check and close the + * container if possible. + */ + if (state == LifeCycleState.QUASI_CLOSED) { + forceCloseContainer(container, replicas); Review comment: True, it will be easy to understand the logic if we return here. 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