| package org.apache.helix.controller.rebalancer; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.helix.controller.dataproviders.ResourceControllerDataProvider; |
| import org.apache.helix.controller.stages.CurrentStateOutput; |
| import org.apache.helix.model.IdealState; |
| import org.apache.helix.model.Partition; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| public class MaintenanceRebalancer extends SemiAutoRebalancer<ResourceControllerDataProvider> { |
| private static final Logger LOG = LoggerFactory.getLogger(MaintenanceRebalancer.class); |
| |
| @Override |
| public IdealState computeNewIdealState(String resourceName, IdealState currentIdealState, |
| CurrentStateOutput currentStateOutput, ResourceControllerDataProvider clusterData) { |
| LOG.info(String |
| .format("Start computing ideal state for resource %s in maintenance mode.", resourceName)); |
| Map<Partition, Map<String, String>> currentStateMap = |
| currentStateOutput.getCurrentStateMap(resourceName); |
| if (currentStateMap == null || currentStateMap.size() == 0) { |
| LOG.warn(String |
| .format("No new partition will be assigned for %s in maintenance mode", resourceName)); |
| |
| // Clear all preference lists, if the resource has not yet been rebalanced, |
| // leave it as is |
| for (List<String> pList : currentIdealState.getPreferenceLists().values()) { |
| pList.clear(); |
| } |
| return currentIdealState; |
| } |
| |
| // One principal is to prohibit DROP -> OFFLINE and OFFLINE -> DROP state transitions. |
| // Derived preference list from current state with state priority |
| for (Partition partition : currentStateMap.keySet()) { |
| Map<String, String> stateMap = currentStateMap.get(partition); |
| List<String> preferenceList = new ArrayList<>(stateMap.keySet()); |
| Collections.sort(preferenceList, new PreferenceListNodeComparator(stateMap, |
| clusterData.getStateModelDef(currentIdealState.getStateModelDefRef()), |
| Collections.<String>emptyList())); |
| currentIdealState.setPreferenceList(partition.getPartitionName(), preferenceList); |
| } |
| LOG.info(String |
| .format("End computing ideal state for resource %s in maintenance mode.", resourceName)); |
| return currentIdealState; |
| } |
| } |