content: /**
   * Copyright 2010 The Apache Software Foundation
   *
   * 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 com.alibaba.wasp.master.balancer;
  
  import com.alibaba.wasp.EntityGroupInfo;
  import com.alibaba.wasp.ServerName;
  import com.alibaba.wasp.master.EntityGroupPlan;
  import com.alibaba.wasp.master.LoadBalancer;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.junit.BeforeClass;
  import org.junit.Test;
  
  import java.util.List;
  import java.util.Map;
  
  /**
   * Test the load balancer that is created by default.
   */
  public class TestDefaultLoadBalancer extends TestBalancerBase {
    private static final Log LOG = LogFactory
        .getLog(TestDefaultLoadBalancer.class);
  
    private static LoadBalancer loadBalancer;
  
    @BeforeClass
    public static void beforeAllTests() throws Exception {
      Configuration conf = HBaseConfiguration.create();
      conf.set("hbase.entityGroups.slop", "0");
      loadBalancer = new DefaultLoadBalancer();
      loadBalancer.setConf(conf);
    }
  
    // int[testnum][servernumber] -> numentityGroups
    int[][] clusterStateMocks = new int[][] {
        // 1 node
        new int[] { 0 },
        new int[] { 1 },
        new int[] { 10 },
        // 2 node
        new int[] { 0, 0 },
        new int[] { 2, 0 },
        new int[] { 2, 1 },
        new int[] { 2, 2 },
        new int[] { 2, 3 },
        new int[] { 2, 4 },
        new int[] { 1, 1 },
        new int[] { 0, 1 },
        new int[] { 10, 1 },
        new int[] { 14, 1432 },
        new int[] { 47, 53 },
        // 3 node
        new int[] { 0, 1, 2 },
        new int[] { 1, 2, 3 },
        new int[] { 0, 2, 2 },
        new int[] { 0, 3, 0 },
        new int[] { 0, 4, 0 },
        new int[] { 20, 20, 0 },
        // 4 node
        new int[] { 0, 1, 2, 3 },
        new int[] { 4, 0, 0, 0 },
        new int[] { 5, 0, 0, 0 },
        new int[] { 6, 6, 0, 0 },
        new int[] { 6, 2, 0, 0 },
        new int[] { 6, 1, 0, 0 },
        new int[] { 6, 0, 0, 0 },
        new int[] { 4, 4, 4, 7 },
        new int[] { 4, 4, 4, 8 },
        new int[] { 0, 0, 0, 7 },
        // 5 node
        new int[] { 1, 1, 1, 1, 4 },
        // more nodes
        new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
        new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 10 },
        new int[] { 6, 6, 5, 6, 6, 6, 6, 6, 6, 1 },
        new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 54 },
        new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 55 },
        new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 56 },
        new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 16 },
        new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 1, 8 },
        new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 1, 9 },
        new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 1, 10 },
        new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 1, 123 },
        new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 1, 155 },
        new int[] { 0, 0, 144, 1, 1, 1, 1, 1123, 133, 138, 12, 1444 },
        new int[] { 0, 0, 144, 1, 0, 4, 1, 1123, 133, 138, 12, 1444 },
        new int[] { 1538, 1392, 1561, 1557, 1535, 1553, 1385, 1542, 1619 } };
  
    /**
     * Test the load balancing algorithm.
     * 
     * Invariant is that all servers should be hosting either floor(average) or
     * ceiling(average)
     * 
     * @throws Exception
     */
    @Test
    public void testBalanceCluster() throws Exception {
  
      for (int[] mockCluster : clusterStateMocks) {
        Map<ServerName, List<EntityGroupInfo>> servers = mockClusterServers(mockCluster);
        List<ServerAndLoad> list = convertToList(servers);
        LOG.info("Mock Cluster : " + printMock(list) + " " + printStats(list));
        List<EntityGroupPlan> plans = loadBalancer.balanceCluster(servers);
        List<ServerAndLoad> balancedCluster = reconcile(list, plans);
        LOG.info("Mock Balance : " + printMock(balancedCluster));
        assertClusterAsBalanced(balancedCluster);
        for (Map.Entry<ServerName, List<EntityGroupInfo>> entry : servers
            .entrySet()) {
          returnEntityGroups(entry.getValue());
          returnServer(entry.getKey());
        }
      }
  
    }
  
  }
  