RejectionReason.java

/**
 * 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.yarn.api.records;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

/**
 * Reason for rejecting a Scheduling Request.
 */
@InterfaceAudience.Public
@InterfaceStability.Unstable
public enum RejectionReason {
  /**
   * This is used to indicate a possible constraint violation. For eg. If the
   * App requested anti-affinity across 5 container requests, but only 4 nodes
   * exist. Another eg. could be if tag A has affinity with tag B and tag B has
   * affinity with tag C, but tag A has anti-affinity with tag C, all at a rack
   * scope - and only 1 rack exists. Essentially all situations where the
   * Algorithm cannot assign a Node to SchedulingRequest.
   */
  COULD_NOT_PLACE_ON_NODE,
  /**
   * This is used to indicate when after the Algorithm has placed a Scheduling
   * Request at a node, but the commit failed because the Queue has no
   * capacity etc. This can be a transient situation.
   */
  COULD_NOT_SCHEDULE_ON_NODE
}