Source code

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.hbase.favored;
019
020import static org.junit.Assert.assertEquals;
021import static org.junit.Assert.assertFalse;
022import static org.junit.Assert.assertNotEquals;
023import static org.junit.Assert.assertNotNull;
024import static org.junit.Assert.assertTrue;
025
026import java.io.IOException;
027import java.util.ArrayList;
028import java.util.HashMap;
029import java.util.List;
030import java.util.Map;
031import java.util.Set;
032import java.util.SortedMap;
033import java.util.TreeMap;
034import org.apache.hadoop.conf.Configuration;
035import org.apache.hadoop.hbase.HBaseClassTestRule;
036import org.apache.hadoop.hbase.HConstants;
037import org.apache.hadoop.hbase.ServerName;
038import org.apache.hadoop.hbase.TableName;
039import org.apache.hadoop.hbase.client.RegionInfo;
040import org.apache.hadoop.hbase.client.RegionInfoBuilder;
041import org.apache.hadoop.hbase.master.RackManager;
042import org.apache.hadoop.hbase.testclassification.MasterTests;
043import org.apache.hadoop.hbase.testclassification.SmallTests;
044import org.apache.hadoop.hbase.util.Bytes;
045import org.apache.hadoop.hbase.util.Triple;
046import org.junit.BeforeClass;
047import org.junit.ClassRule;
048import org.junit.Rule;
049import org.junit.Test;
050import org.junit.experimental.categories.Category;
051import org.junit.rules.TestName;
052import org.mockito.Mockito;
053
054import org.apache.hbase.thirdparty.com.google.common.collect.Lists;
055import org.apache.hbase.thirdparty.com.google.common.collect.Sets;
056
057@Category({MasterTests.class, SmallTests.class})
058public class TestFavoredNodeAssignmentHelper {
059
060  @ClassRule
061  public static final HBaseClassTestRule CLASS_RULE =
062      HBaseClassTestRule.forClass(TestFavoredNodeAssignmentHelper.class);
063
064  private static List<ServerName> servers = new ArrayList<>();
065  private static Map<String, List<ServerName>> rackToServers = new HashMap<>();
066  private static RackManager rackManager = Mockito.mock(RackManager.class);
067
068  // Some tests have randomness, so we run them multiple times
069  private static final int MAX_ATTEMPTS = 100;
070
071  @Rule
072  public TestName name = new TestName();
073
074  @BeforeClass
075  public static void setupBeforeClass() throws Exception {
076    // Set up some server -> rack mappings
077    // Have three racks in the cluster with 10 hosts each.
078    for (int i = 0; i < 40; i++) {
079      ServerName server = ServerName.valueOf("foo" + i + ":1234", -1);
080      if (i < 10) {
081        Mockito.when(rackManager.getRack(server)).thenReturn("rack1");
082        if (rackToServers.get("rack1") == null) {
083          List<ServerName> servers = new ArrayList<>();
084          rackToServers.put("rack1", servers);
085        }
086        rackToServers.get("rack1").add(server);
087      }
088      if (i >= 10 && i < 20) {
089        Mockito.when(rackManager.getRack(server)).thenReturn("rack2");
090        if (rackToServers.get("rack2") == null) {
091          List<ServerName> servers = new ArrayList<>();
092          rackToServers.put("rack2", servers);
093        }
094        rackToServers.get("rack2").add(server);
095      }
096      if (i >= 20 && i < 30) {
097        Mockito.when(rackManager.getRack(server)).thenReturn("rack3");
098        if (rackToServers.get("rack3") == null) {
099          List<ServerName> servers = new ArrayList<>();
100          rackToServers.put("rack3", servers);
101        }
102        rackToServers.get("rack3").add(server);
103      }
104      servers.add(server);
105    }
106  }
107
108  // The tests decide which racks to work with, and how many machines to
109  // work with from any given rack
110  // Return a rondom 'count' number of servers from 'rack'
111  private static List<ServerName> getServersFromRack(Map<String, Integer> rackToServerCount) {
112    List<ServerName> chosenServers = new ArrayList<>();
113    for (Map.Entry<String, Integer> entry : rackToServerCount.entrySet()) {
114      List<ServerName> servers = rackToServers.get(entry.getKey());
115      for (int i = 0; i < entry.getValue(); i++) {
116        chosenServers.add(servers.get(i));
117      }
118    }
119    return chosenServers;
120  }
121
122  @Test
123  public void testSmallCluster() {
124    // Test the case where we cannot assign favored nodes (because the number
125    // of nodes in the cluster is too less)
126    Map<String,Integer> rackToServerCount = new HashMap<>();
127    rackToServerCount.put("rack1", 2);
128    List<ServerName> servers = getServersFromRack(rackToServerCount);
129    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers,
130        new Configuration());
131    helper.initialize();
132    assertFalse(helper.canPlaceFavoredNodes());
133  }
134
135  @Test
136  public void testPlacePrimaryRSAsRoundRobin() {
137    // Test the regular case where there are many servers in different racks
138    // Test once for few regions and once for many regions
139    primaryRSPlacement(6, null, 10, 10, 10);
140    // now create lots of regions and try to place them on the limited number of machines
141    primaryRSPlacement(600, null, 10, 10, 10);
142  }
143
144  @Test
145  public void testRoundRobinAssignmentsWithUnevenSizedRacks() {
146    //In the case of uneven racks, the regions should be distributed
147    //proportionately to the rack sizes
148    primaryRSPlacement(6, null, 10, 10, 10);
149    primaryRSPlacement(600, null, 10, 10, 5);
150    primaryRSPlacement(600, null, 10, 5, 10);
151    primaryRSPlacement(600, null, 5, 10, 10);
152    primaryRSPlacement(500, null, 10, 10, 5);
153    primaryRSPlacement(500, null, 10, 5, 10);
154    primaryRSPlacement(500, null, 5, 10, 10);
155    primaryRSPlacement(500, null, 9, 7, 8);
156    primaryRSPlacement(500, null, 8, 7, 9);
157    primaryRSPlacement(500, null, 7, 9, 8);
158    primaryRSPlacement(459, null, 7, 9, 8);
159  }
160
161  @Test
162  public void testSecondaryAndTertiaryPlacementWithSingleRack() {
163    // Test the case where there is a single rack and we need to choose
164    // Primary/Secondary/Tertiary from a single rack.
165    Map<String,Integer> rackToServerCount = new HashMap<>();
166    rackToServerCount.put("rack1", 10);
167    // have lots of regions to test with
168    Triple<Map<RegionInfo, ServerName>, FavoredNodeAssignmentHelper, List<RegionInfo>>
169      primaryRSMapAndHelper = secondaryAndTertiaryRSPlacementHelper(60000, rackToServerCount);
170    FavoredNodeAssignmentHelper helper = primaryRSMapAndHelper.getSecond();
171    Map<RegionInfo, ServerName> primaryRSMap = primaryRSMapAndHelper.getFirst();
172    List<RegionInfo> regions = primaryRSMapAndHelper.getThird();
173    Map<RegionInfo, ServerName[]> secondaryAndTertiaryMap =
174        helper.placeSecondaryAndTertiaryRS(primaryRSMap);
175    // although we created lots of regions we should have no overlap on the
176    // primary/secondary/tertiary for any given region
177    for (RegionInfo region : regions) {
178      ServerName[] secondaryAndTertiaryServers = secondaryAndTertiaryMap.get(region);
179      assertNotNull(secondaryAndTertiaryServers);
180      assertTrue(primaryRSMap.containsKey(region));
181      assertTrue(!secondaryAndTertiaryServers[0].equals(primaryRSMap.get(region)));
182      assertTrue(!secondaryAndTertiaryServers[1].equals(primaryRSMap.get(region)));
183      assertTrue(!secondaryAndTertiaryServers[0].equals(secondaryAndTertiaryServers[1]));
184    }
185  }
186
187  @Test
188  public void testSecondaryAndTertiaryPlacementWithSingleServer() {
189    // Test the case where we have a single node in the cluster. In this case
190    // the primary can be assigned but the secondary/tertiary would be null
191    Map<String,Integer> rackToServerCount = new HashMap<>();
192    rackToServerCount.put("rack1", 1);
193    Triple<Map<RegionInfo, ServerName>, FavoredNodeAssignmentHelper, List<RegionInfo>>
194      primaryRSMapAndHelper = secondaryAndTertiaryRSPlacementHelper(1, rackToServerCount);
195    FavoredNodeAssignmentHelper helper = primaryRSMapAndHelper.getSecond();
196    Map<RegionInfo, ServerName> primaryRSMap = primaryRSMapAndHelper.getFirst();
197    List<RegionInfo> regions = primaryRSMapAndHelper.getThird();
198
199    Map<RegionInfo, ServerName[]> secondaryAndTertiaryMap =
200        helper.placeSecondaryAndTertiaryRS(primaryRSMap);
201    // no secondary/tertiary placement in case of a single RegionServer
202    assertTrue(secondaryAndTertiaryMap.get(regions.get(0)) == null);
203  }
204
205  @Test
206  public void testSecondaryAndTertiaryPlacementWithMultipleRacks() {
207    // Test the case where we have multiple racks and the region servers
208    // belong to multiple racks
209    Map<String,Integer> rackToServerCount = new HashMap<>();
210    rackToServerCount.put("rack1", 10);
211    rackToServerCount.put("rack2", 10);
212
213    Triple<Map<RegionInfo, ServerName>, FavoredNodeAssignmentHelper, List<RegionInfo>>
214      primaryRSMapAndHelper = secondaryAndTertiaryRSPlacementHelper(60000, rackToServerCount);
215    FavoredNodeAssignmentHelper helper = primaryRSMapAndHelper.getSecond();
216    Map<RegionInfo, ServerName> primaryRSMap = primaryRSMapAndHelper.getFirst();
217
218    assertTrue(primaryRSMap.size() == 60000);
219    Map<RegionInfo, ServerName[]> secondaryAndTertiaryMap =
220        helper.placeSecondaryAndTertiaryRS(primaryRSMap);
221    assertTrue(secondaryAndTertiaryMap.size() == 60000);
222    // for every region, the primary should be on one rack and the secondary/tertiary
223    // on another (we create a lot of regions just to increase probability of failure)
224    for (Map.Entry<RegionInfo, ServerName[]> entry : secondaryAndTertiaryMap.entrySet()) {
225      ServerName[] allServersForRegion = entry.getValue();
226      String primaryRSRack = rackManager.getRack(primaryRSMap.get(entry.getKey()));
227      String secondaryRSRack = rackManager.getRack(allServersForRegion[0]);
228      String tertiaryRSRack = rackManager.getRack(allServersForRegion[1]);
229      Set<String> racks = Sets.newHashSet(primaryRSRack);
230      racks.add(secondaryRSRack);
231      racks.add(tertiaryRSRack);
232      assertTrue(racks.size() >= 2);
233    }
234  }
235
236  @Test
237  public void testSecondaryAndTertiaryPlacementWithLessThanTwoServersInRacks() {
238    // Test the case where we have two racks but with less than two servers in each
239    // We will not have enough machines to select secondary/tertiary
240    Map<String,Integer> rackToServerCount = new HashMap<>();
241    rackToServerCount.put("rack1", 1);
242    rackToServerCount.put("rack2", 1);
243    Triple<Map<RegionInfo, ServerName>, FavoredNodeAssignmentHelper, List<RegionInfo>>
244      primaryRSMapAndHelper = secondaryAndTertiaryRSPlacementHelper(6, rackToServerCount);
245    FavoredNodeAssignmentHelper helper = primaryRSMapAndHelper.getSecond();
246    Map<RegionInfo, ServerName> primaryRSMap = primaryRSMapAndHelper.getFirst();
247    List<RegionInfo> regions = primaryRSMapAndHelper.getThird();
248    assertTrue(primaryRSMap.size() == 6);
249    Map<RegionInfo, ServerName[]> secondaryAndTertiaryMap =
250          helper.placeSecondaryAndTertiaryRS(primaryRSMap);
251    for (RegionInfo region : regions) {
252      // not enough secondary/tertiary room to place the regions
253      assertTrue(secondaryAndTertiaryMap.get(region) == null);
254    }
255  }
256
257  @Test
258  public void testSecondaryAndTertiaryPlacementWithMoreThanOneServerInPrimaryRack() {
259    // Test the case where there is only one server in one rack and another rack
260    // has more servers. We try to choose secondary/tertiary on different
261    // racks than what the primary is on. But if the other rack doesn't have
262    // enough nodes to have both secondary/tertiary RSs, the tertiary is placed
263    // on the same rack as the primary server is on
264    Map<String,Integer> rackToServerCount = new HashMap<>();
265    rackToServerCount.put("rack1", 2);
266    rackToServerCount.put("rack2", 1);
267    Triple<Map<RegionInfo, ServerName>, FavoredNodeAssignmentHelper, List<RegionInfo>>
268      primaryRSMapAndHelper = secondaryAndTertiaryRSPlacementHelper(6, rackToServerCount);
269    FavoredNodeAssignmentHelper helper = primaryRSMapAndHelper.getSecond();
270    Map<RegionInfo, ServerName> primaryRSMap = primaryRSMapAndHelper.getFirst();
271    List<RegionInfo> regions = primaryRSMapAndHelper.getThird();
272    assertTrue(primaryRSMap.size() == 6);
273    Map<RegionInfo, ServerName[]> secondaryAndTertiaryMap =
274          helper.placeSecondaryAndTertiaryRS(primaryRSMap);
275    assertTrue(secondaryAndTertiaryMap.size() == regions.size());
276    for (RegionInfo region : regions) {
277      ServerName s = primaryRSMap.get(region);
278      ServerName secondaryRS = secondaryAndTertiaryMap.get(region)[0];
279      ServerName tertiaryRS = secondaryAndTertiaryMap.get(region)[1];
280      Set<String> racks = Sets.newHashSet(rackManager.getRack(s));
281      racks.add(rackManager.getRack(secondaryRS));
282      racks.add(rackManager.getRack(tertiaryRS));
283      assertTrue(racks.size() >= 2);
284    }
285  }
286
287  private Triple<Map<RegionInfo, ServerName>, FavoredNodeAssignmentHelper, List<RegionInfo>>
288  secondaryAndTertiaryRSPlacementHelper(
289      int regionCount, Map<String, Integer> rackToServerCount) {
290    Map<RegionInfo, ServerName> primaryRSMap = new HashMap<RegionInfo, ServerName>();
291    List<ServerName> servers = getServersFromRack(rackToServerCount);
292    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
293    Map<ServerName, List<RegionInfo>> assignmentMap =
294        new HashMap<ServerName, List<RegionInfo>>();
295    helper.initialize();
296    // create regions
297    List<RegionInfo> regions = new ArrayList<>(regionCount);
298    for (int i = 0; i < regionCount; i++) {
299      regions.add(RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
300          .setStartKey(Bytes.toBytes(i))
301          .setEndKey(Bytes.toBytes(i + 1))
302          .build());
303    }
304    // place the regions
305    helper.placePrimaryRSAsRoundRobin(assignmentMap, primaryRSMap, regions);
306    return new Triple<>(primaryRSMap, helper, regions);
307  }
308
309  private void primaryRSPlacement(int regionCount, Map<RegionInfo, ServerName> primaryRSMap,
310      int firstRackSize, int secondRackSize, int thirdRackSize) {
311    Map<String,Integer> rackToServerCount = new HashMap<>();
312    rackToServerCount.put("rack1", firstRackSize);
313    rackToServerCount.put("rack2", secondRackSize);
314    rackToServerCount.put("rack3", thirdRackSize);
315    List<ServerName> servers = getServersFromRack(rackToServerCount);
316    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers,
317        rackManager);
318    helper.initialize();
319
320    assertTrue(helper.canPlaceFavoredNodes());
321
322    Map<ServerName, List<RegionInfo>> assignmentMap = new HashMap<>();
323    if (primaryRSMap == null) primaryRSMap = new HashMap<>();
324    // create some regions
325    List<RegionInfo> regions = new ArrayList<>(regionCount);
326    for (int i = 0; i < regionCount; i++) {
327      regions.add(RegionInfoBuilder.newBuilder(TableName.valueOf("foobar"))
328          .setStartKey(Bytes.toBytes(i))
329          .setEndKey(Bytes.toBytes(i + 1))
330          .build());
331    }
332    // place those regions in primary RSs
333    helper.placePrimaryRSAsRoundRobin(assignmentMap, primaryRSMap, regions);
334
335    // we should have all the regions nicely spread across the racks
336    int regionsOnRack1 = 0;
337    int regionsOnRack2 = 0;
338    int regionsOnRack3 = 0;
339    for (RegionInfo region : regions) {
340      if (rackManager.getRack(primaryRSMap.get(region)).equals("rack1")) {
341        regionsOnRack1++;
342      } else if (rackManager.getRack(primaryRSMap.get(region)).equals("rack2")) {
343        regionsOnRack2++;
344      } else if (rackManager.getRack(primaryRSMap.get(region)).equals("rack3")) {
345        regionsOnRack3++;
346      }
347    }
348    // Verify that the regions got placed in the way we expect (documented in
349    // FavoredNodeAssignmentHelper#placePrimaryRSAsRoundRobin)
350    checkNumRegions(regionCount, firstRackSize, secondRackSize, thirdRackSize, regionsOnRack1,
351        regionsOnRack2, regionsOnRack3, assignmentMap);
352  }
353
354  private void checkNumRegions(int regionCount, int firstRackSize, int secondRackSize,
355      int thirdRackSize, int regionsOnRack1, int regionsOnRack2, int regionsOnRack3,
356      Map<ServerName, List<RegionInfo>> assignmentMap) {
357    //The regions should be distributed proportionately to the racksizes
358    //Verify the ordering was as expected by inserting the racks and regions
359    //in sorted maps. The keys being the racksize and numregions; values are
360    //the relative positions of the racksizes and numregions respectively
361    SortedMap<Integer, Integer> rackMap = new TreeMap<>();
362    rackMap.put(firstRackSize, 1);
363    rackMap.put(secondRackSize, 2);
364    rackMap.put(thirdRackSize, 3);
365    SortedMap<Integer, Integer> regionMap = new TreeMap<>();
366    regionMap.put(regionsOnRack1, 1);
367    regionMap.put(regionsOnRack2, 2);
368    regionMap.put(regionsOnRack3, 3);
369    assertTrue(printProportions(firstRackSize, secondRackSize, thirdRackSize,
370        regionsOnRack1, regionsOnRack2, regionsOnRack3),
371        rackMap.get(firstRackSize) == regionMap.get(regionsOnRack1));
372    assertTrue(printProportions(firstRackSize, secondRackSize, thirdRackSize,
373        regionsOnRack1, regionsOnRack2, regionsOnRack3),
374        rackMap.get(secondRackSize) == regionMap.get(regionsOnRack2));
375    assertTrue(printProportions(firstRackSize, secondRackSize, thirdRackSize,
376        regionsOnRack1, regionsOnRack2, regionsOnRack3),
377        rackMap.get(thirdRackSize) == regionMap.get(regionsOnRack3));
378  }
379
380  private String printProportions(int firstRackSize, int secondRackSize,
381      int thirdRackSize, int regionsOnRack1, int regionsOnRack2, int regionsOnRack3) {
382    return "The rack sizes " + firstRackSize + " " + secondRackSize
383        + " " + thirdRackSize + " " + regionsOnRack1 + " " + regionsOnRack2 +
384        " " + regionsOnRack3;
385  }
386
387  @Test
388  public void testConstrainedPlacement() throws Exception {
389    List<ServerName> servers = Lists.newArrayList();
390    servers.add(ServerName.valueOf("foo" + 1 + ":1234", -1));
391    servers.add(ServerName.valueOf("foo" + 2 + ":1234", -1));
392    servers.add(ServerName.valueOf("foo" + 15 + ":1234", -1));
393    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
394    helper.initialize();
395    assertTrue(helper.canPlaceFavoredNodes());
396
397    List<RegionInfo> regions = new ArrayList<>(20);
398    for (int i = 0; i < 20; i++) {
399      regions.add(RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
400          .setStartKey(Bytes.toBytes(i))
401          .setEndKey(Bytes.toBytes(i + 1))
402          .build());
403    }
404    Map<ServerName, List<RegionInfo>> assignmentMap =
405        new HashMap<ServerName, List<RegionInfo>>();
406    Map<RegionInfo, ServerName> primaryRSMap = new HashMap<RegionInfo, ServerName>();
407    helper.placePrimaryRSAsRoundRobin(assignmentMap, primaryRSMap, regions);
408    assertTrue(primaryRSMap.size() == regions.size());
409    Map<RegionInfo, ServerName[]> secondaryAndTertiary =
410        helper.placeSecondaryAndTertiaryRS(primaryRSMap);
411    assertEquals(regions.size(), secondaryAndTertiary.size());
412  }
413
414  @Test
415  public void testGetOneRandomRack() throws IOException {
416
417    Map<String,Integer> rackToServerCount = new HashMap<>();
418    Set<String> rackList = Sets.newHashSet("rack1", "rack2", "rack3");
419    for (String rack : rackList) {
420      rackToServerCount.put(rack, 2);
421    }
422    List<ServerName> servers = getServersFromRack(rackToServerCount);
423
424    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
425    helper.initialize();
426    assertTrue(helper.canPlaceFavoredNodes());
427
428    // Check we don't get a bad rack on any number of attempts
429    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
430      assertTrue(rackList.contains(helper.getOneRandomRack(Sets.newHashSet())));
431    }
432
433    // Check skipRack multiple times when an invalid rack is specified
434    Set<String> skipRacks = Sets.newHashSet("rack");
435    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
436      assertTrue(rackList.contains(helper.getOneRandomRack(skipRacks)));
437    }
438
439    // Check skipRack multiple times when an valid rack is specified
440    skipRacks = Sets.newHashSet("rack1");
441    Set<String> validRacks = Sets.newHashSet("rack2", "rack3");
442    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
443      assertTrue(validRacks.contains(helper.getOneRandomRack(skipRacks)));
444    }
445  }
446
447  @Test
448  public void testGetRandomServerSingleRack() throws IOException {
449
450    Map<String,Integer> rackToServerCount = new HashMap<>();
451    final String rack = "rack1";
452    rackToServerCount.put(rack, 4);
453    List<ServerName> servers = getServersFromRack(rackToServerCount);
454
455    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
456    helper.initialize();
457    assertTrue(helper.canPlaceFavoredNodes());
458
459    // Check we don't get a bad node on any number of attempts
460    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
461      ServerName sn = helper.getOneRandomServer(rack, Sets.newHashSet());
462      assertTrue("Server:" + sn + " does not belong to list: " + servers, servers.contains(sn));
463    }
464
465    // Check skipServers multiple times when an invalid server is specified
466    Set<ServerName> skipServers =
467        Sets.newHashSet(ServerName.valueOf("invalidnode:1234", ServerName.NON_STARTCODE));
468    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
469      ServerName sn = helper.getOneRandomServer(rack, skipServers);
470      assertTrue("Server:" + sn + " does not belong to list: " + servers, servers.contains(sn));
471    }
472
473    // Check skipRack multiple times when an valid servers are specified
474    ServerName skipSN = ServerName.valueOf("foo1:1234", ServerName.NON_STARTCODE);
475    skipServers = Sets.newHashSet(skipSN);
476    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
477      ServerName sn = helper.getOneRandomServer(rack, skipServers);
478      assertNotEquals("Skip server should not be selected ",
479          skipSN.getHostAndPort(), sn.getHostAndPort());
480      assertTrue("Server:" + sn + " does not belong to list: " + servers, servers.contains(sn));
481    }
482  }
483
484  @Test
485  public void testGetRandomServerMultiRack() throws IOException {
486    Map<String,Integer> rackToServerCount = new HashMap<>();
487    Set<String> rackList = Sets.newHashSet("rack1", "rack2", "rack3");
488    for (String rack : rackList) {
489      rackToServerCount.put(rack, 4);
490    }
491    List<ServerName> servers = getServersFromRack(rackToServerCount);
492
493    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
494    helper.initialize();
495    assertTrue(helper.canPlaceFavoredNodes());
496
497    // Check we don't get a bad node on any number of attempts
498    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
499      for (String rack : rackList) {
500        ServerName sn = helper.getOneRandomServer(rack, Sets.newHashSet());
501        assertTrue("Server:" + sn + " does not belong to rack servers: " + rackToServers.get(rack),
502            rackToServers.get(rack).contains(sn));
503      }
504    }
505
506    // Check skipServers multiple times when an invalid server is specified
507    Set<ServerName> skipServers =
508        Sets.newHashSet(ServerName.valueOf("invalidnode:1234", ServerName.NON_STARTCODE));
509    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
510      for (String rack : rackList) {
511        ServerName sn = helper.getOneRandomServer(rack, skipServers);
512        assertTrue("Server:" + sn + " does not belong to rack servers: " + rackToServers.get(rack),
513            rackToServers.get(rack).contains(sn));
514      }
515    }
516
517    // Check skipRack multiple times when an valid servers are specified
518    ServerName skipSN1 = ServerName.valueOf("foo1:1234", ServerName.NON_STARTCODE);
519    ServerName skipSN2 = ServerName.valueOf("foo10:1234", ServerName.NON_STARTCODE);
520    ServerName skipSN3 = ServerName.valueOf("foo20:1234", ServerName.NON_STARTCODE);
521    skipServers = Sets.newHashSet(skipSN1, skipSN2, skipSN3);
522    for (int attempts = 0 ; attempts < MAX_ATTEMPTS; attempts++) {
523      for (String rack : rackList) {
524        ServerName sn = helper.getOneRandomServer(rack, skipServers);
525        assertFalse("Skip server should not be selected ", skipServers.contains(sn));
526        assertTrue("Server:" + sn + " does not belong to rack servers: " + rackToServers.get(rack),
527            rackToServers.get(rack).contains(sn));
528      }
529    }
530  }
531
532  @Test
533  public void testGetFavoredNodes() throws IOException {
534    Map<String,Integer> rackToServerCount = new HashMap<>();
535    Set<String> rackList = Sets.newHashSet("rack1", "rack2", "rack3");
536    for (String rack : rackList) {
537      rackToServerCount.put(rack, 4);
538    }
539    List<ServerName> servers = getServersFromRack(rackToServerCount);
540
541    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
542    helper.initialize();
543    assertTrue(helper.canPlaceFavoredNodes());
544
545    RegionInfo region = RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
546        .setStartKey(HConstants.EMPTY_START_ROW)
547        .setEndKey(HConstants.EMPTY_END_ROW)
548        .build();
549
550    for (int maxattempts = 0; maxattempts < MAX_ATTEMPTS; maxattempts++) {
551      List<ServerName> fn = helper.generateFavoredNodes(region);
552      checkDuplicateFN(fn);
553      checkFNRacks(fn);
554    }
555  }
556
557  @Test
558  public void testGenMissingFavoredNodeOneRack() throws IOException {
559    Map<String, Integer> rackToServerCount = new HashMap<>();
560    final String rack = "rack1";
561    rackToServerCount.put(rack, 6);
562    List<ServerName> servers = getServersFromRack(rackToServerCount);
563
564    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
565    helper.initialize();
566    assertTrue(helper.canPlaceFavoredNodes());
567
568
569    ServerName snRack1SN1 = ServerName.valueOf("foo1:1234", ServerName.NON_STARTCODE);
570    ServerName snRack1SN2 = ServerName.valueOf("foo2:1234", ServerName.NON_STARTCODE);
571    ServerName snRack1SN3 = ServerName.valueOf("foo3:1234", ServerName.NON_STARTCODE);
572
573    List<ServerName> fn = Lists.newArrayList(snRack1SN1, snRack1SN2);
574    for (int attempts = 0; attempts < MAX_ATTEMPTS; attempts++) {
575      checkDuplicateFN(fn, helper.generateMissingFavoredNode(fn));
576    }
577
578    fn = Lists.newArrayList(snRack1SN1, snRack1SN2);
579    List<ServerName> skipServers = Lists.newArrayList(snRack1SN3);
580    for (int attempts = 0; attempts < MAX_ATTEMPTS; attempts++) {
581      ServerName genSN = helper.generateMissingFavoredNode(fn, skipServers);
582      checkDuplicateFN(fn, genSN);
583      assertNotEquals("Generated FN should not match excluded one", snRack1SN3, genSN);
584    }
585  }
586
587  @Test
588  public void testGenMissingFavoredNodeMultiRack() throws IOException {
589
590    ServerName snRack1SN1 = ServerName.valueOf("foo1:1234", ServerName.NON_STARTCODE);
591    ServerName snRack1SN2 = ServerName.valueOf("foo2:1234", ServerName.NON_STARTCODE);
592    ServerName snRack2SN1 = ServerName.valueOf("foo10:1234", ServerName.NON_STARTCODE);
593    ServerName snRack2SN2 = ServerName.valueOf("foo11:1234", ServerName.NON_STARTCODE);
594
595    Map<String,Integer> rackToServerCount = new HashMap<>();
596    Set<String> rackList = Sets.newHashSet("rack1", "rack2");
597    for (String rack : rackList) {
598      rackToServerCount.put(rack, 4);
599    }
600    List<ServerName> servers = getServersFromRack(rackToServerCount);
601
602    FavoredNodeAssignmentHelper helper = new FavoredNodeAssignmentHelper(servers, rackManager);
603    helper.initialize();
604    assertTrue(helper.canPlaceFavoredNodes());
605
606    List<ServerName> fn = Lists.newArrayList(snRack1SN1, snRack1SN2);
607    for (int attempts = 0; attempts < MAX_ATTEMPTS; attempts++) {
608      ServerName genSN = helper.generateMissingFavoredNode(fn);
609      checkDuplicateFN(fn, genSN);
610      checkFNRacks(fn, genSN);
611    }
612
613    fn = Lists.newArrayList(snRack1SN1, snRack2SN1);
614    for (int attempts = 0; attempts < MAX_ATTEMPTS; attempts++) {
615      ServerName genSN = helper.generateMissingFavoredNode(fn);
616      checkDuplicateFN(fn, genSN);
617      checkFNRacks(fn, genSN);
618    }
619
620    fn = Lists.newArrayList(snRack1SN1, snRack2SN1);
621    List<ServerName> skipServers = Lists.newArrayList(snRack2SN2);
622    for (int attempts = 0; attempts < MAX_ATTEMPTS; attempts++) {
623      ServerName genSN = helper.generateMissingFavoredNode(fn, skipServers);
624      checkDuplicateFN(fn, genSN);
625      checkFNRacks(fn, genSN);
626      assertNotEquals("Generated FN should not match excluded one", snRack2SN2, genSN);
627    }
628  }
629
630  private void checkDuplicateFN(List<ServerName> fnList, ServerName genFN) {
631    Set<ServerName> favoredNodes = Sets.newHashSet(fnList);
632    assertNotNull("Generated FN can't be null", genFN);
633    favoredNodes.add(genFN);
634    assertEquals("Did not find expected number of favored nodes",
635        FavoredNodeAssignmentHelper.FAVORED_NODES_NUM, favoredNodes.size());
636  }
637
638  private void checkDuplicateFN(List<ServerName> fnList) {
639    Set<ServerName> favoredNodes = Sets.newHashSet(fnList);
640    assertEquals("Did not find expected number of favored nodes",
641        FavoredNodeAssignmentHelper.FAVORED_NODES_NUM, favoredNodes.size());
642  }
643
644  private void checkFNRacks(List<ServerName> fnList, ServerName genFN) {
645    Set<ServerName> favoredNodes = Sets.newHashSet(fnList);
646    favoredNodes.add(genFN);
647    Set<String> racks = Sets.newHashSet();
648    for (ServerName sn : favoredNodes) {
649      racks.add(rackManager.getRack(sn));
650    }
651    assertTrue("FN should be spread atleast across 2 racks", racks.size() >= 2);
652  }
653
654  private void checkFNRacks(List<ServerName> fnList) {
655    Set<ServerName> favoredNodes = Sets.newHashSet(fnList);
656    Set<String> racks = Sets.newHashSet();
657    for (ServerName sn : favoredNodes) {
658      racks.add(rackManager.getRack(sn));
659    }
660    assertTrue("FN should be spread atleast across 2 racks", racks.size() >= 2);
661  }
662}