| /** |
| * 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.federation.policies.router; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Random; |
| |
| import org.apache.hadoop.yarn.api.records.ApplicationSubmissionContext; |
| import org.apache.hadoop.yarn.exceptions.YarnException; |
| import org.apache.hadoop.yarn.server.federation.policies.FederationPolicyInitializationContext; |
| import org.apache.hadoop.yarn.server.federation.policies.FederationPolicyInitializationContextValidator; |
| import org.apache.hadoop.yarn.server.federation.policies.FederationPolicyUtils; |
| import org.apache.hadoop.yarn.server.federation.policies.exceptions.FederationPolicyInitializationException; |
| import org.apache.hadoop.yarn.server.federation.store.records.SubClusterId; |
| import org.apache.hadoop.yarn.server.federation.store.records.SubClusterInfo; |
| |
| /** |
| * This simple policy picks at uniform random among any of the currently active |
| * subclusters. This policy is easy to use and good for testing. |
| * |
| * NOTE: this is "almost" subsumed by the {@code WeightedRandomRouterPolicy}. |
| * Behavior only diverges when there are active sub-clusters that are not part |
| * of the "weights", in which case the {@link UniformRandomRouterPolicy} send |
| * load to them, while {@code WeightedRandomRouterPolicy} does not. |
| */ |
| public class UniformRandomRouterPolicy extends AbstractRouterPolicy { |
| |
| private Random rand; |
| |
| public UniformRandomRouterPolicy() { |
| rand = new Random(System.currentTimeMillis()); |
| } |
| |
| @Override |
| public void reinitialize(FederationPolicyInitializationContext policyContext) |
| throws FederationPolicyInitializationException { |
| FederationPolicyInitializationContextValidator.validate(policyContext, |
| this.getClass().getCanonicalName()); |
| |
| // note: this overrides AbstractRouterPolicy and ignores the weights |
| |
| setPolicyContext(policyContext); |
| } |
| |
| /** |
| * Simply picks a random active subCluster to start the AM (this does NOT |
| * depend on the weights in the policy). |
| * |
| * @param appSubmissionContext the {@link ApplicationSubmissionContext} that |
| * has to be routed to an appropriate subCluster for execution. |
| * |
| * @param blackListSubClusters the list of subClusters as identified by |
| * {@link SubClusterId} to blackList from the selection of the home |
| * subCluster. |
| * |
| * @return a randomly chosen subcluster. |
| * |
| * @throws YarnException if there are no active subclusters. |
| */ |
| @Override |
| public SubClusterId getHomeSubcluster( |
| ApplicationSubmissionContext appSubmissionContext, |
| List<SubClusterId> blackListSubClusters) throws YarnException { |
| |
| // null checks and default-queue behavior |
| validate(appSubmissionContext); |
| |
| Map<SubClusterId, SubClusterInfo> activeSubclusters = |
| getActiveSubclusters(); |
| |
| List<SubClusterId> list = new ArrayList<>(activeSubclusters.keySet()); |
| |
| FederationPolicyUtils.validateSubClusterAvailability(list, |
| blackListSubClusters); |
| |
| if (blackListSubClusters != null) { |
| |
| // Remove from the active SubClusters from StateStore the blacklisted ones |
| for (SubClusterId scId : blackListSubClusters) { |
| list.remove(scId); |
| } |
| } |
| |
| return list.get(rand.nextInt(list.size())); |
| } |
| |
| } |