001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.yarn.api.records;
019
020import java.util.List;
021import java.util.Set;
022
023import org.apache.hadoop.classification.InterfaceAudience.Private;
024import org.apache.hadoop.classification.InterfaceAudience.Public;
025import org.apache.hadoop.classification.InterfaceStability.Evolving;
026import org.apache.hadoop.classification.InterfaceStability.Unstable;
027import org.apache.hadoop.yarn.api.protocolrecords.AllocateRequest;
028import org.apache.hadoop.yarn.util.Records;
029
030/**
031 * Description of resources requested back by the <code>ResourceManager</code>.
032 * The <code>ApplicationMaster</code> (AM) can satisfy this request according
033 * to its own priorities to prevent containers from being forcibly killed by
034 * the platform.
035 * @see PreemptionMessage
036 */
037@Public
038@Evolving
039public abstract class PreemptionContract {
040
041  @Private
042  @Unstable
043  public static PreemptionContract newInstance(
044      List<PreemptionResourceRequest> req, Set<PreemptionContainer> containers) {
045    PreemptionContract contract = Records.newRecord(PreemptionContract.class);
046    contract.setResourceRequest(req);
047    contract.setContainers(containers);
048    return contract;
049  }
050
051  /**
052   * If the AM releases resources matching these requests, then the {@link
053   * PreemptionContainer}s enumerated in {@link #getContainers()} should not be
054   * evicted from the cluster. Due to delays in propagating cluster state and
055   * sending these messages, there are conditions where satisfied contracts may
056   * not prevent the platform from killing containers.
057   * @return List of {@link PreemptionResourceRequest} to update the
058   * <code>ApplicationMaster</code> about resources requested back by the
059   * <code>ResourceManager</code>.
060   * @see AllocateRequest#setAskList(List)
061   */
062  @Public
063  @Evolving
064  public abstract List<PreemptionResourceRequest> getResourceRequest();
065
066  @Private
067  @Unstable
068  public abstract void setResourceRequest(List<PreemptionResourceRequest> req);
069
070  /**
071   * Assign the set of {@link PreemptionContainer} specifying which containers
072   * owned by the <code>ApplicationMaster</code> that may be reclaimed by the
073   * <code>ResourceManager</code>. If the AM prefers a different set of
074   * containers, then it may checkpoint or kill containers matching the
075   * description in {@link #getResourceRequest}.
076   * @return Set of containers at risk if the contract is not met.
077   */
078  @Public
079  @Evolving
080  public abstract Set<PreemptionContainer> getContainers();
081
082
083  @Private
084  @Unstable
085  public abstract void setContainers(Set<PreemptionContainer> containers);
086
087}