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Posted to commits@helix.apache.org by lx...@apache.org on 2017/02/08 17:59:55 UTC
[20/38] helix git commit: Refactor: add AbstractRebalancer as an
abstract class,
which contains the default implementations as well as utility functions that
will be used by all specific rebalancers.
Refactor: add AbstractRebalancer as an abstract class, which contains the default implementations as well as utility functions that will be used by all specific rebalancers.
Project: http://git-wip-us.apache.org/repos/asf/helix/repo
Commit: http://git-wip-us.apache.org/repos/asf/helix/commit/9e8ec454
Tree: http://git-wip-us.apache.org/repos/asf/helix/tree/9e8ec454
Diff: http://git-wip-us.apache.org/repos/asf/helix/diff/9e8ec454
Branch: refs/heads/helix-0.6.x
Commit: 9e8ec4544b2f827f7e1e2ab118962a85f2e86076
Parents: 24d7700
Author: Lei Xia <lx...@linkedin.com>
Authored: Mon Sep 12 10:59:40 2016 -0700
Committer: Lei Xia <lx...@linkedin.com>
Committed: Wed Feb 8 09:50:40 2017 -0800
----------------------------------------------------------------------
.../rebalancer/AbstractRebalancer.java | 166 ++++
.../controller/rebalancer/AutoRebalancer.java | 112 +--
.../controller/rebalancer/CustomRebalancer.java | 9 +-
.../rebalancer/SemiAutoRebalancer.java | 44 +-
.../rebalancer/TestAutoRebalanceStrategy.java | 765 +++++++++++++++++
.../strategy/TestAutoRebalanceStrategy.java | 853 -------------------
.../helix/controller/strategy/TestTopology.java | 2 +-
7 files changed, 935 insertions(+), 1016 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/helix/blob/9e8ec454/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AbstractRebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AbstractRebalancer.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AbstractRebalancer.java
new file mode 100644
index 0000000..e0e831a
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AbstractRebalancer.java
@@ -0,0 +1,166 @@
+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 org.apache.helix.HelixManager;
+import org.apache.helix.controller.rebalancer.internal.MappingCalculator;
+import org.apache.helix.controller.rebalancer.strategy.RebalanceStrategy;
+import org.apache.helix.controller.rebalancer.util.ConstraintBasedAssignment;
+import org.apache.helix.controller.stages.ClusterDataCache;
+import org.apache.helix.controller.stages.CurrentStateOutput;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.Partition;
+import org.apache.helix.model.Resource;
+import org.apache.helix.model.ResourceAssignment;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.log4j.Logger;
+
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * This is a abstract rebalancer that defines some default behaviors for Helix rebalancer
+ * as well as all utility functions that will be used by all specific rebalancers.
+ */
+public abstract class AbstractRebalancer implements Rebalancer, MappingCalculator {
+ // These should be final, but are initialized in init rather than a constructor
+ protected HelixManager _manager;
+ protected RebalanceStrategy _rebalanceStrategy;
+
+ private static final Logger LOG = Logger.getLogger(AbstractRebalancer.class);
+
+ @Override
+ public void init(HelixManager manager) {
+ this._manager = manager;
+ this._rebalanceStrategy = null;
+ }
+
+ @Override
+ public abstract IdealState computeNewIdealState(String resourceName, IdealState currentIdealState,
+ CurrentStateOutput currentStateOutput, ClusterDataCache clusterData);
+
+ /**
+ * Compute the best state for all partitions.
+ * This is the default ConstraintBasedAssignment implementation, subclasses should re-implement
+ * this method if its logic to generate bestpossible map for each partition is different from the default one here.
+ *
+ * @param cache
+ * @param idealState
+ * @param resource
+ * @param currentStateOutput
+ * Provides the current state and pending state transitions for all partitions
+ * @return
+ */
+ @Override
+ public ResourceAssignment computeBestPossiblePartitionState(ClusterDataCache cache,
+ IdealState idealState, Resource resource, CurrentStateOutput currentStateOutput) {
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Processing resource:" + resource.getResourceName());
+ }
+ String stateModelDefName = idealState.getStateModelDefRef();
+ StateModelDefinition stateModelDef = cache.getStateModelDef(stateModelDefName);
+ ResourceAssignment partitionMapping = new ResourceAssignment(resource.getResourceName());
+ for (Partition partition : resource.getPartitions()) {
+ Map<String, String> currentStateMap =
+ currentStateOutput.getCurrentStateMap(resource.getResourceName(), partition);
+ Set<String> disabledInstancesForPartition =
+ cache.getDisabledInstancesForPartition(partition.toString());
+ List<String> preferenceList =
+ ConstraintBasedAssignment.getPreferenceList(cache, partition, idealState, stateModelDef);
+ Map<String, String> bestStateForPartition =
+ ConstraintBasedAssignment.computeAutoBestStateForPartition(cache, stateModelDef,
+ preferenceList, currentStateMap, disabledInstancesForPartition,
+ idealState.isEnabled());
+ partitionMapping.addReplicaMap(partition, bestStateForPartition);
+ }
+ return partitionMapping;
+ }
+
+ /**
+ * @return state count map: state->count
+ */
+ protected static LinkedHashMap<String, Integer> stateCount(StateModelDefinition stateModelDef,
+ int liveNodesNb, int totalReplicas) {
+ LinkedHashMap<String, Integer> stateCountMap = new LinkedHashMap<String, Integer>();
+ List<String> statesPriorityList = stateModelDef.getStatesPriorityList();
+
+ int replicas = totalReplicas;
+ for (String state : statesPriorityList) {
+ String num = stateModelDef.getNumInstancesPerState(state);
+ if ("N".equals(num)) {
+ stateCountMap.put(state, liveNodesNb);
+ } else if ("R".equals(num)) {
+ // wait until we get the counts for all other states
+ continue;
+ } else {
+ int stateCount = -1;
+ try {
+ stateCount = Integer.parseInt(num);
+ } catch (Exception e) {
+ // LOG.error("Invalid count for state: " + state + ", count: " + num +
+ // ", use -1 instead");
+ }
+
+ if (stateCount > 0) {
+ stateCountMap.put(state, stateCount);
+ replicas -= stateCount;
+ }
+ }
+ }
+
+ // get state count for R
+ for (String state : statesPriorityList) {
+ String num = stateModelDef.getNumInstancesPerState(state);
+ if ("R".equals(num)) {
+ stateCountMap.put(state, replicas);
+ // should have at most one state using R
+ break;
+ }
+ }
+ return stateCountMap;
+ }
+
+ protected Map<String, Map<String, String>> currentMapping(CurrentStateOutput currentStateOutput,
+ String resourceName, List<String> partitions, Map<String, Integer> stateCountMap) {
+
+ Map<String, Map<String, String>> map = new HashMap<String, Map<String, String>>();
+
+ for (String partition : partitions) {
+ Map<String, String> curStateMap =
+ currentStateOutput.getCurrentStateMap(resourceName, new Partition(partition));
+ map.put(partition, new HashMap<String, String>());
+ for (String node : curStateMap.keySet()) {
+ String state = curStateMap.get(node);
+ map.get(partition).put(node, state);
+ }
+
+ Map<String, String> pendingStateMap =
+ currentStateOutput.getPendingStateMap(resourceName, new Partition(partition));
+ for (String node : pendingStateMap.keySet()) {
+ String state = pendingStateMap.get(node);
+ map.get(partition).put(node, state);
+ }
+ }
+ return map;
+ }
+}
http://git-wip-us.apache.org/repos/asf/helix/blob/9e8ec454/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AutoRebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AutoRebalancer.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AutoRebalancer.java
index ba237b1..74f8b6e 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AutoRebalancer.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/AutoRebalancer.java
@@ -21,7 +21,6 @@ package org.apache.helix.controller.rebalancer;
import java.util.ArrayList;
import java.util.Collections;
-import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
@@ -29,10 +28,7 @@ import java.util.Map;
import java.util.Set;
import org.apache.helix.HelixException;
-import org.apache.helix.HelixManager;
import org.apache.helix.ZNRecord;
-import org.apache.helix.controller.rebalancer.internal.MappingCalculator;
-import org.apache.helix.controller.rebalancer.util.ConstraintBasedAssignment;
import org.apache.helix.controller.stages.ClusterDataCache;
import org.apache.helix.controller.stages.CurrentStateOutput;
import org.apache.helix.controller.rebalancer.strategy.AutoRebalanceStrategy;
@@ -40,9 +36,6 @@ import org.apache.helix.controller.rebalancer.strategy.RebalanceStrategy;
import org.apache.helix.model.IdealState;
import org.apache.helix.model.IdealState.RebalanceMode;
import org.apache.helix.model.LiveInstance;
-import org.apache.helix.model.Partition;
-import org.apache.helix.model.Resource;
-import org.apache.helix.model.ResourceAssignment;
import org.apache.helix.model.StateModelDefinition;
import org.apache.helix.util.HelixUtil;
import org.apache.log4j.Logger;
@@ -57,20 +50,10 @@ import org.apache.log4j.Logger;
* The output is a preference list and a mapping based on that preference list, i.e. partition p
* has a replica on node k with state s.
*/
-public class AutoRebalancer implements Rebalancer, MappingCalculator {
- // These should be final, but are initialized in init rather than a constructor
- private HelixManager _manager;
- private RebalanceStrategy _rebalanceStrategy;
-
+public class AutoRebalancer extends AbstractRebalancer {
private static final Logger LOG = Logger.getLogger(AutoRebalancer.class);
@Override
- public void init(HelixManager manager) {
- this._manager = manager;
- this._rebalanceStrategy = null;
- }
-
- @Override
public IdealState computeNewIdealState(String resourceName, IdealState currentIdealState,
CurrentStateOutput currentStateOutput, ClusterDataCache clusterData) {
List<String> partitions = new ArrayList<String>(currentIdealState.getPartitionSet());
@@ -171,97 +154,4 @@ public class AutoRebalancer implements Rebalancer, MappingCalculator {
newIdealState.getRecord().setListFields(newMapping.getListFields());
return newIdealState;
}
-
- /**
- * @return state count map: state->count
- */
- public static LinkedHashMap<String, Integer> stateCount(StateModelDefinition stateModelDef,
- int liveNodesNb, int totalReplicas) {
- LinkedHashMap<String, Integer> stateCountMap = new LinkedHashMap<String, Integer>();
- List<String> statesPriorityList = stateModelDef.getStatesPriorityList();
-
- int replicas = totalReplicas;
- for (String state : statesPriorityList) {
- String num = stateModelDef.getNumInstancesPerState(state);
- if ("N".equals(num)) {
- stateCountMap.put(state, liveNodesNb);
- } else if ("R".equals(num)) {
- // wait until we get the counts for all other states
- continue;
- } else {
- int stateCount = -1;
- try {
- stateCount = Integer.parseInt(num);
- } catch (Exception e) {
- // LOG.error("Invalid count for state: " + state + ", count: " + num +
- // ", use -1 instead");
- }
-
- if (stateCount > 0) {
- stateCountMap.put(state, stateCount);
- replicas -= stateCount;
- }
- }
- }
-
- // get state count for R
- for (String state : statesPriorityList) {
- String num = stateModelDef.getNumInstancesPerState(state);
- if ("R".equals(num)) {
- stateCountMap.put(state, replicas);
- // should have at most one state using R
- break;
- }
- }
- return stateCountMap;
- }
-
- private Map<String, Map<String, String>> currentMapping(CurrentStateOutput currentStateOutput,
- String resourceName, List<String> partitions, Map<String, Integer> stateCountMap) {
-
- Map<String, Map<String, String>> map = new HashMap<String, Map<String, String>>();
-
- for (String partition : partitions) {
- Map<String, String> curStateMap =
- currentStateOutput.getCurrentStateMap(resourceName, new Partition(partition));
- map.put(partition, new HashMap<String, String>());
- for (String node : curStateMap.keySet()) {
- String state = curStateMap.get(node);
- map.get(partition).put(node, state);
- }
-
- Map<String, String> pendingStateMap =
- currentStateOutput.getPendingStateMap(resourceName, new Partition(partition));
- for (String node : pendingStateMap.keySet()) {
- String state = pendingStateMap.get(node);
- map.get(partition).put(node, state);
- }
- }
- return map;
- }
-
- @Override
- public ResourceAssignment computeBestPossiblePartitionState(ClusterDataCache cache,
- IdealState idealState, Resource resource, CurrentStateOutput currentStateOutput) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Processing resource:" + resource.getResourceName());
- }
- String stateModelDefName = idealState.getStateModelDefRef();
- StateModelDefinition stateModelDef = cache.getStateModelDef(stateModelDefName);
- ResourceAssignment partitionMapping = new ResourceAssignment(resource.getResourceName());
- for (Partition partition : resource.getPartitions()) {
- Map<String, String> currentStateMap =
- currentStateOutput.getCurrentStateMap(resource.getResourceName(), partition);
- Set<String> disabledInstancesForPartition =
- cache.getDisabledInstancesForPartition(partition.toString());
- List<String> preferenceList =
- ConstraintBasedAssignment.getPreferenceList(cache, partition, idealState, stateModelDef);
- Map<String, String> bestStateForPartition =
- ConstraintBasedAssignment.computeAutoBestStateForPartition(cache, stateModelDef,
- preferenceList, currentStateMap, disabledInstancesForPartition,
- idealState.isEnabled());
- partitionMapping.addReplicaMap(partition, bestStateForPartition);
- }
- return partitionMapping;
- }
}
http://git-wip-us.apache.org/repos/asf/helix/blob/9e8ec454/helix-core/src/main/java/org/apache/helix/controller/rebalancer/CustomRebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/CustomRebalancer.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/CustomRebalancer.java
index 21ad2ff..a4f5e83 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/CustomRebalancer.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/CustomRebalancer.java
@@ -24,8 +24,6 @@ import java.util.Map;
import java.util.Set;
import org.apache.helix.HelixDefinedState;
-import org.apache.helix.HelixManager;
-import org.apache.helix.controller.rebalancer.internal.MappingCalculator;
import org.apache.helix.controller.stages.ClusterDataCache;
import org.apache.helix.controller.stages.CurrentStateOutput;
import org.apache.helix.model.IdealState;
@@ -45,15 +43,10 @@ import org.apache.log4j.Logger;
* The output is a verified mapping based on that preference list, i.e. partition p has a replica
* on node k with state s, where s may be a dropped or error state if necessary.
*/
-public class CustomRebalancer implements Rebalancer, MappingCalculator {
-
+public class CustomRebalancer extends AbstractRebalancer {
private static final Logger LOG = Logger.getLogger(CustomRebalancer.class);
@Override
- public void init(HelixManager manager) {
- }
-
- @Override
public IdealState computeNewIdealState(String resourceName, IdealState currentIdealState,
CurrentStateOutput currentStateOutput, ClusterDataCache clusterData) {
return currentIdealState;
http://git-wip-us.apache.org/repos/asf/helix/blob/9e8ec454/helix-core/src/main/java/org/apache/helix/controller/rebalancer/SemiAutoRebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/SemiAutoRebalancer.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/SemiAutoRebalancer.java
index 86c0438..6ef93c1 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/SemiAutoRebalancer.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/SemiAutoRebalancer.java
@@ -18,21 +18,9 @@ package org.apache.helix.controller.rebalancer;
* specific language governing permissions and limitations
* under the License.
*/
-
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-import org.apache.helix.HelixManager;
-import org.apache.helix.controller.rebalancer.internal.MappingCalculator;
-import org.apache.helix.controller.rebalancer.util.ConstraintBasedAssignment;
import org.apache.helix.controller.stages.ClusterDataCache;
import org.apache.helix.controller.stages.CurrentStateOutput;
import org.apache.helix.model.IdealState;
-import org.apache.helix.model.Partition;
-import org.apache.helix.model.Resource;
-import org.apache.helix.model.ResourceAssignment;
-import org.apache.helix.model.StateModelDefinition;
import org.apache.log4j.Logger;
/**
@@ -44,42 +32,12 @@ import org.apache.log4j.Logger;
* The output is a mapping based on that preference list, i.e. partition p has a replica on node k
* with state s.
*/
-public class SemiAutoRebalancer implements Rebalancer, MappingCalculator {
-
+public class SemiAutoRebalancer extends AbstractRebalancer {
private static final Logger LOG = Logger.getLogger(SemiAutoRebalancer.class);
@Override
- public void init(HelixManager manager) {
- }
-
- @Override
public IdealState computeNewIdealState(String resourceName, IdealState currentIdealState,
CurrentStateOutput currentStateOutput, ClusterDataCache clusterData) {
return currentIdealState;
}
-
- @Override
- public ResourceAssignment computeBestPossiblePartitionState(ClusterDataCache cache,
- IdealState idealState, Resource resource, CurrentStateOutput currentStateOutput) {
- String stateModelDefName = idealState.getStateModelDefRef();
- StateModelDefinition stateModelDef = cache.getStateModelDef(stateModelDefName);
- if (LOG.isDebugEnabled()) {
- LOG.debug("Processing resource:" + resource.getResourceName());
- }
- ResourceAssignment partitionMapping = new ResourceAssignment(resource.getResourceName());
- for (Partition partition : resource.getPartitions()) {
- Map<String, String> currentStateMap =
- currentStateOutput.getCurrentStateMap(resource.getResourceName(), partition);
- Set<String> disabledInstancesForPartition =
- cache.getDisabledInstancesForPartition(partition.toString());
- List<String> preferenceList =
- ConstraintBasedAssignment.getPreferenceList(cache, partition, idealState, stateModelDef);
- Map<String, String> bestStateForPartition =
- ConstraintBasedAssignment.computeAutoBestStateForPartition(cache, stateModelDef,
- preferenceList, currentStateMap, disabledInstancesForPartition,
- idealState.isEnabled());
- partitionMapping.addReplicaMap(partition, bestStateForPartition);
- }
- return partitionMapping;
- }
}
http://git-wip-us.apache.org/repos/asf/helix/blob/9e8ec454/helix-core/src/test/java/org/apache/helix/controller/rebalancer/TestAutoRebalanceStrategy.java
----------------------------------------------------------------------
diff --git a/helix-core/src/test/java/org/apache/helix/controller/rebalancer/TestAutoRebalanceStrategy.java b/helix-core/src/test/java/org/apache/helix/controller/rebalancer/TestAutoRebalanceStrategy.java
new file mode 100644
index 0000000..9f70f29
--- /dev/null
+++ b/helix-core/src/test/java/org/apache/helix/controller/rebalancer/TestAutoRebalanceStrategy.java
@@ -0,0 +1,765 @@
+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.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Random;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+import org.apache.helix.HelixDefinedState;
+import org.apache.helix.Mocks.MockAccessor;
+import org.apache.helix.PropertyKey.Builder;
+import org.apache.helix.ZNRecord;
+import org.apache.helix.controller.rebalancer.strategy.AutoRebalanceStrategy;
+import org.apache.helix.controller.rebalancer.strategy.RebalanceStrategy;
+import org.apache.helix.controller.rebalancer.util.ConstraintBasedAssignment;
+import org.apache.helix.controller.stages.ClusterDataCache;
+import org.apache.helix.model.LiveInstance;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.helix.tools.StateModelConfigGenerator;
+import org.apache.log4j.Logger;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+
+public class TestAutoRebalanceStrategy {
+ private static Logger logger = Logger.getLogger(TestAutoRebalanceStrategy.class);
+
+ /**
+ * Sanity test for a basic Master-Slave model
+ */
+ @Test
+ public void simpleMasterSlaveTest() {
+ final int NUM_ITERATIONS = 10;
+ final int NUM_PARTITIONS = 10;
+ final int NUM_LIVE_NODES = 12;
+ final int NUM_TOTAL_NODES = 20;
+ final int MAX_PER_NODE = 5;
+
+ final String[] STATE_NAMES = {
+ "MASTER", "SLAVE"
+ };
+ final int[] STATE_COUNTS = {
+ 1, 2
+ };
+
+ runTest("BasicMasterSlave", NUM_ITERATIONS, NUM_PARTITIONS, NUM_LIVE_NODES, NUM_TOTAL_NODES,
+ MAX_PER_NODE, STATE_NAMES, STATE_COUNTS);
+ }
+
+ /**
+ * Run a test for an arbitrary state model.
+ * @param name Name of the test state model
+ * @param numIterations Number of rebalance tasks to run
+ * @param numPartitions Number of partitions for the resource
+ * @param numLiveNodes Number of live nodes in the cluster
+ * @param numTotalNodes Number of nodes in the cluster, must be greater than or equal to
+ * numLiveNodes
+ * @param maxPerNode Maximum number of replicas a node can serve
+ * @param stateNames States ordered by preference
+ * @param stateCounts Number of replicas that should be in each state
+ */
+ private void runTest(String name, int numIterations, int numPartitions, int numLiveNodes,
+ int numTotalNodes, int maxPerNode, String[] stateNames, int[] stateCounts) {
+ List<String> partitions = new ArrayList<String>();
+ for (int i = 0; i < numPartitions; i++) {
+ partitions.add("p_" + i);
+ }
+
+ List<String> liveNodes = new ArrayList<String>();
+ List<String> allNodes = new ArrayList<String>();
+ for (int i = 0; i < numTotalNodes; i++) {
+ allNodes.add("n_" + i);
+ if (i < numLiveNodes) {
+ liveNodes.add("n_" + i);
+ }
+ }
+
+ Map<String, Map<String, String>> currentMapping = new TreeMap<String, Map<String, String>>();
+
+ LinkedHashMap<String, Integer> states = new LinkedHashMap<String, Integer>();
+ for (int i = 0; i < Math.min(stateNames.length, stateCounts.length); i++) {
+ states.put(stateNames[i], stateCounts[i]);
+ }
+
+ StateModelDefinition stateModelDef = getIncompleteStateModelDef(name, stateNames[0], states);
+
+ new AutoRebalanceTester(partitions, states, liveNodes, currentMapping, allNodes, maxPerNode,
+ stateModelDef).runRepeatedly(numIterations);
+ }
+
+ /**
+ * Get a StateModelDefinition without transitions. The auto rebalancer doesn't take transitions
+ * into account when computing mappings, so this is acceptable.
+ * @param modelName name to give the model
+ * @param initialState initial state for all nodes
+ * @param states ordered map of state to count
+ * @return incomplete StateModelDefinition for rebalancing
+ */
+ private StateModelDefinition getIncompleteStateModelDef(String modelName, String initialState,
+ LinkedHashMap<String, Integer> states) {
+ StateModelDefinition.Builder builder = new StateModelDefinition.Builder(modelName);
+ builder.initialState(initialState);
+ int i = states.size();
+ for (String state : states.keySet()) {
+ builder.addState(state, i);
+ builder.upperBound(state, states.get(state));
+ i--;
+ }
+ return builder.build();
+ }
+
+ class AutoRebalanceTester {
+ private static final double P_KILL = 0.45;
+ private static final double P_ADD = 0.1;
+ private static final double P_RESURRECT = 0.45;
+ private static final String RESOURCE_NAME = "resource";
+
+ private List<String> _partitions;
+ private LinkedHashMap<String, Integer> _states;
+ private List<String> _liveNodes;
+ private Set<String> _liveSet;
+ private Set<String> _removedSet;
+ private Set<String> _nonLiveSet;
+ private Map<String, Map<String, String>> _currentMapping;
+ private List<String> _allNodes;
+ private int _maxPerNode;
+ private StateModelDefinition _stateModelDef;
+ private Random _random;
+
+ public AutoRebalanceTester(List<String> partitions, LinkedHashMap<String, Integer> states,
+ List<String> liveNodes, Map<String, Map<String, String>> currentMapping,
+ List<String> allNodes, int maxPerNode, StateModelDefinition stateModelDef) {
+ _partitions = partitions;
+ _states = states;
+ _liveNodes = liveNodes;
+ _liveSet = new TreeSet<String>();
+ for (String node : _liveNodes) {
+ _liveSet.add(node);
+ }
+ _removedSet = new TreeSet<String>();
+ _nonLiveSet = new TreeSet<String>();
+ _currentMapping = currentMapping;
+ _allNodes = allNodes;
+ for (String node : allNodes) {
+ if (!_liveSet.contains(node)) {
+ _nonLiveSet.add(node);
+ }
+ }
+ _maxPerNode = maxPerNode;
+ _stateModelDef = stateModelDef;
+ _random = new Random();
+ }
+
+ /**
+ * Repeatedly randomly select a task to run and report the result
+ * @param numIterations
+ * Number of random tasks to run in sequence
+ */
+ public void runRepeatedly(int numIterations) {
+ logger.info("~~~~ Initial State ~~~~~");
+ RebalanceStrategy strategy =
+ new AutoRebalanceStrategy(RESOURCE_NAME, _partitions, _states, _maxPerNode);
+ ZNRecord initialResult =
+ strategy.computePartitionAssignment(_allNodes, _liveNodes, _currentMapping, null);
+ _currentMapping = getMapping(initialResult.getListFields());
+ logger.info(_currentMapping);
+ getRunResult(_currentMapping, initialResult.getListFields());
+ for (int i = 0; i < numIterations; i++) {
+ logger.info("~~~~ Iteration " + i + " ~~~~~");
+ ZNRecord znRecord = runOnceRandomly();
+ if (znRecord != null) {
+ final Map<String, List<String>> listResult = znRecord.getListFields();
+ final Map<String, Map<String, String>> mapResult = getMapping(listResult);
+ logger.info(mapResult);
+ logger.info(listResult);
+ getRunResult(mapResult, listResult);
+ _currentMapping = mapResult;
+ }
+ }
+ }
+
+ private Map<String, Map<String, String>> getMapping(final Map<String, List<String>> listResult) {
+ final Map<String, Map<String, String>> mapResult = new HashMap<String, Map<String, String>>();
+ ClusterDataCache cache = new ClusterDataCache();
+ MockAccessor accessor = new MockAccessor();
+ Builder keyBuilder = accessor.keyBuilder();
+ for (String node : _liveNodes) {
+ LiveInstance liveInstance = new LiveInstance(node);
+ liveInstance.setSessionId("testSession");
+ accessor.setProperty(keyBuilder.liveInstance(node), liveInstance);
+ }
+ cache.refresh(accessor);
+ for (String partition : _partitions) {
+ List<String> preferenceList = listResult.get(partition);
+ Map<String, String> currentStateMap = _currentMapping.get(partition);
+ Set<String> disabled = Collections.emptySet();
+ Map<String, String> assignment =
+ ConstraintBasedAssignment.computeAutoBestStateForPartition(cache, _stateModelDef,
+ preferenceList, currentStateMap, disabled, true);
+ mapResult.put(partition, assignment);
+ }
+ return mapResult;
+ }
+
+ /**
+ * Output various statistics and correctness check results
+ * @param mapFields
+ * The map-map assignment generated by the rebalancer
+ * @param listFields
+ * The map-list assignment generated by the rebalancer
+ */
+ public void getRunResult(final Map<String, Map<String, String>> mapFields,
+ final Map<String, List<String>> listFields) {
+ logger.info("***** Statistics *****");
+ dumpStatistics(mapFields);
+ verifyCorrectness(mapFields, listFields);
+ }
+
+ /**
+ * Output statistics about the assignment
+ * @param mapFields
+ * The map-map assignment generated by the rebalancer
+ */
+ public void dumpStatistics(final Map<String, Map<String, String>> mapFields) {
+ Map<String, Integer> partitionsPerNode = getPartitionBucketsForNode(mapFields);
+ int nodeCount = _liveNodes.size();
+ logger.info("Total number of nodes: " + nodeCount);
+ logger.info("Nodes: " + _liveNodes);
+ int sumPartitions = getSum(partitionsPerNode.values());
+ logger.info("Total number of partitions: " + sumPartitions);
+ double averagePartitions = getAverage(partitionsPerNode.values());
+ logger.info("Average number of partitions per node: " + averagePartitions);
+ double stdevPartitions = getStdev(partitionsPerNode.values(), averagePartitions);
+ logger.info("Standard deviation of partitions: " + stdevPartitions);
+
+ // Statistics about each state
+ Map<String, Map<String, Integer>> statesPerNode = getStateBucketsForNode(mapFields);
+ for (String state : _states.keySet()) {
+ Map<String, Integer> nodeStateCounts = new TreeMap<String, Integer>();
+ for (Entry<String, Map<String, Integer>> nodeStates : statesPerNode.entrySet()) {
+ Map<String, Integer> stateCounts = nodeStates.getValue();
+ if (stateCounts.containsKey(state)) {
+ nodeStateCounts.put(nodeStates.getKey(), stateCounts.get(state));
+ } else {
+ nodeStateCounts.put(nodeStates.getKey(), 0);
+ }
+ }
+ int sumStates = getSum(nodeStateCounts.values());
+ logger.info("Total number of state " + state + ": " + sumStates);
+ double averageStates = getAverage(nodeStateCounts.values());
+ logger.info("Average number of state " + state + " per node: " + averageStates);
+ double stdevStates = getStdev(nodeStateCounts.values(), averageStates);
+ logger.info("Standard deviation of state " + state + " per node: " + stdevStates);
+ }
+ }
+
+ /**
+ * Run a set of correctness tests, reporting success or failure
+ * @param mapFields
+ * The map-map assignment generated by the rebalancer
+ * @param listFields
+ * The map-list assignment generated by the rebalancer
+ */
+ public void verifyCorrectness(final Map<String, Map<String, String>> mapFields,
+ final Map<String, List<String>> listFields) {
+ final Map<String, Integer> partitionsPerNode = getPartitionBucketsForNode(mapFields);
+ boolean maxConstraintMet = maxNotExceeded(partitionsPerNode);
+ assert maxConstraintMet : "Max per node constraint: FAIL";
+ logger.info("Max per node constraint: PASS");
+
+ boolean liveConstraintMet = onlyLiveAssigned(partitionsPerNode);
+ assert liveConstraintMet : "Only live nodes have partitions constraint: FAIL";
+ logger.info("Only live nodes have partitions constraint: PASS");
+
+ boolean stateAssignmentPossible = correctStateAssignmentCount(mapFields);
+ assert stateAssignmentPossible : "State replica constraint: FAIL";
+ logger.info("State replica constraint: PASS");
+
+ boolean nodesUniqueForPartitions = atMostOnePartitionReplicaPerNode(listFields);
+ assert nodesUniqueForPartitions : "Node uniqueness per partition constraint: FAIL";
+ logger.info("Node uniqueness per partition constraint: PASS");
+ }
+
+ private boolean maxNotExceeded(final Map<String, Integer> partitionsPerNode) {
+ for (String node : partitionsPerNode.keySet()) {
+ Integer value = partitionsPerNode.get(node);
+ if (value > _maxPerNode) {
+ logger.error("ERROR: Node " + node + " has " + value
+ + " partitions despite a maximum of " + _maxPerNode);
+ return false;
+ }
+ }
+ return true;
+ }
+
+ private boolean onlyLiveAssigned(final Map<String, Integer> partitionsPerNode) {
+ for (final Entry<String, Integer> nodeState : partitionsPerNode.entrySet()) {
+ boolean isLive = _liveSet.contains(nodeState.getKey());
+ boolean isEmpty = nodeState.getValue() == 0;
+ if (!isLive && !isEmpty) {
+ logger.error("ERROR: Node " + nodeState.getKey() + " is not live, but has "
+ + nodeState.getValue() + " replicas!");
+ return false;
+ }
+ }
+ return true;
+ }
+
+ private boolean correctStateAssignmentCount(final Map<String, Map<String, String>> assignment) {
+ for (final Entry<String, Map<String, String>> partitionEntry : assignment.entrySet()) {
+ final Map<String, String> nodeMap = partitionEntry.getValue();
+ final Map<String, Integer> stateCounts = new TreeMap<String, Integer>();
+ for (String state : nodeMap.values()) {
+ if (!stateCounts.containsKey(state)) {
+ stateCounts.put(state, 1);
+ } else {
+ stateCounts.put(state, stateCounts.get(state) + 1);
+ }
+ }
+ for (String state : stateCounts.keySet()) {
+ if (state.equals(HelixDefinedState.DROPPED.toString())) {
+ continue;
+ }
+ int count = stateCounts.get(state);
+ int maximumCount = _states.get(state);
+ if (count > maximumCount) {
+ logger.error("ERROR: State " + state + " for partition " + partitionEntry.getKey()
+ + " has " + count + " replicas when " + maximumCount + " is allowed!");
+ return false;
+ }
+ }
+ }
+ return true;
+ }
+
+ private boolean atMostOnePartitionReplicaPerNode(final Map<String, List<String>> listFields) {
+ for (final Entry<String, List<String>> partitionEntry : listFields.entrySet()) {
+ Set<String> nodeSet = new HashSet<String>(partitionEntry.getValue());
+ int numUniques = nodeSet.size();
+ int total = partitionEntry.getValue().size();
+ if (numUniques < total) {
+ logger.error("ERROR: Partition " + partitionEntry.getKey() + " is assigned to " + total
+ + " nodes, but only " + numUniques + " are unique!");
+ return false;
+ }
+ }
+ return true;
+ }
+
+ private double getAverage(final Collection<Integer> values) {
+ double sum = 0.0;
+ for (Integer value : values) {
+ sum += value;
+ }
+ if (values.size() != 0) {
+ return sum / values.size();
+ } else {
+ return -1.0;
+ }
+ }
+
+ private int getSum(final Collection<Integer> values) {
+ int sum = 0;
+ for (Integer value : values) {
+ sum += value;
+ }
+ return sum;
+ }
+
+ private double getStdev(final Collection<Integer> values, double mean) {
+ double sum = 0.0;
+ for (Integer value : values) {
+ double deviation = mean - value;
+ sum += Math.pow(deviation, 2.0);
+ }
+ if (values.size() != 0) {
+ sum /= values.size();
+ return Math.pow(sum, 0.5);
+ } else {
+ return -1.0;
+ }
+ }
+
+ private Map<String, Integer> getPartitionBucketsForNode(
+ final Map<String, Map<String, String>> assignment) {
+ Map<String, Integer> partitionsPerNode = new TreeMap<String, Integer>();
+ for (String node : _liveNodes) {
+ partitionsPerNode.put(node, 0);
+ }
+ for (Entry<String, Map<String, String>> partitionEntry : assignment.entrySet()) {
+ final Map<String, String> nodeMap = partitionEntry.getValue();
+ for (String node : nodeMap.keySet()) {
+ String state = nodeMap.get(node);
+ if (state.equals(HelixDefinedState.DROPPED.toString())) {
+ continue;
+ }
+ // add 1 for every occurrence of a node
+ if (!partitionsPerNode.containsKey(node)) {
+ partitionsPerNode.put(node, 1);
+ } else {
+ partitionsPerNode.put(node, partitionsPerNode.get(node) + 1);
+ }
+ }
+ }
+ return partitionsPerNode;
+ }
+
+ private Map<String, Map<String, Integer>> getStateBucketsForNode(
+ final Map<String, Map<String, String>> assignment) {
+ Map<String, Map<String, Integer>> result = new TreeMap<String, Map<String, Integer>>();
+ for (String n : _liveNodes) {
+ result.put(n, new TreeMap<String, Integer>());
+ }
+ for (Map<String, String> nodeStateMap : assignment.values()) {
+ for (Entry<String, String> nodeState : nodeStateMap.entrySet()) {
+ if (!result.containsKey(nodeState.getKey())) {
+ result.put(nodeState.getKey(), new TreeMap<String, Integer>());
+ }
+ Map<String, Integer> stateMap = result.get(nodeState.getKey());
+ if (!stateMap.containsKey(nodeState.getValue())) {
+ stateMap.put(nodeState.getValue(), 1);
+ } else {
+ stateMap.put(nodeState.getValue(), stateMap.get(nodeState.getValue()) + 1);
+ }
+ }
+ }
+ return result;
+ }
+
+ /**
+ * Randomly choose between killing, adding, or resurrecting a single node
+ * @return (Partition -> (Node -> State)) ZNRecord
+ */
+ public ZNRecord runOnceRandomly() {
+ double choose = _random.nextDouble();
+ ZNRecord result = null;
+ if (choose < P_KILL) {
+ result = removeSingleNode(null);
+ } else if (choose < P_KILL + P_ADD) {
+ result = addSingleNode(null);
+ } else if (choose < P_KILL + P_ADD + P_RESURRECT) {
+ result = resurrectSingleNode(null);
+ }
+ return result;
+ }
+
+ /**
+ * Run rebalancer trying to add a never-live node
+ * @param node
+ * Optional String to add
+ * @return ZNRecord result returned by the rebalancer
+ */
+ public ZNRecord addSingleNode(String node) {
+ logger.info("=================== add node =================");
+ if (_nonLiveSet.size() == 0) {
+ logger.warn("Cannot add node because there are no nodes left to add.");
+ return null;
+ }
+
+ // Get a random never-live node
+ if (node == null || !_nonLiveSet.contains(node)) {
+ node = getRandomSetElement(_nonLiveSet);
+ }
+ logger.info("Adding " + node);
+ _liveNodes.add(node);
+ _liveSet.add(node);
+ _nonLiveSet.remove(node);
+
+ return new AutoRebalanceStrategy(RESOURCE_NAME, _partitions, _states, _maxPerNode).
+ computePartitionAssignment(_allNodes, _liveNodes, _currentMapping, null);
+ }
+
+ /**
+ * Run rebalancer trying to remove a live node
+ * @param node
+ * Optional String to remove
+ * @return ZNRecord result returned by the rebalancer
+ */
+ public ZNRecord removeSingleNode(String node) {
+ logger.info("=================== remove node =================");
+ if (_liveSet.size() == 0) {
+ logger.warn("Cannot remove node because there are no nodes left to remove.");
+ return null;
+ }
+
+ // Get a random never-live node
+ if (node == null || !_liveSet.contains(node)) {
+ node = getRandomSetElement(_liveSet);
+ }
+ logger.info("Removing " + node);
+ _removedSet.add(node);
+ _liveNodes.remove(node);
+ _liveSet.remove(node);
+
+ // the rebalancer expects that the current mapping doesn't contain deleted
+ // nodes
+ for (Map<String, String> nodeMap : _currentMapping.values()) {
+ if (nodeMap.containsKey(node)) {
+ nodeMap.remove(node);
+ }
+ }
+
+ return new AutoRebalanceStrategy(RESOURCE_NAME, _partitions, _states, _maxPerNode)
+ .computePartitionAssignment(_allNodes, _liveNodes, _currentMapping, null);
+ }
+
+ /**
+ * Run rebalancer trying to add back a removed node
+ * @param node
+ * Optional String to resurrect
+ * @return ZNRecord result returned by the rebalancer
+ */
+ public ZNRecord resurrectSingleNode(String node) {
+ logger.info("=================== resurrect node =================");
+ if (_removedSet.size() == 0) {
+ logger.warn("Cannot remove node because there are no nodes left to resurrect.");
+ return null;
+ }
+
+ // Get a random never-live node
+ if (node == null || !_removedSet.contains(node)) {
+ node = getRandomSetElement(_removedSet);
+ }
+ logger.info("Resurrecting " + node);
+ _removedSet.remove(node);
+ _liveNodes.add(node);
+ _liveSet.add(node);
+
+ return new AutoRebalanceStrategy(RESOURCE_NAME, _partitions, _states, _maxPerNode)
+ .computePartitionAssignment(_allNodes, _liveNodes, _currentMapping, null);
+ }
+
+ private <T> T getRandomSetElement(Set<T> source) {
+ int element = _random.nextInt(source.size());
+ int i = 0;
+ for (T node : source) {
+ if (i == element) {
+ return node;
+ }
+ i++;
+ }
+ return null;
+ }
+ }
+
+ /**
+ * Tests the following scenario: nodes come up one by one, then one node is taken down. Preference
+ * lists should prefer nodes in the current mapping at all times, but when all nodes are in the
+ * current mapping, then it should distribute states as evenly as possible.
+ */
+ @Test
+ public void testOrphansNotPreferred() {
+ final String RESOURCE_NAME = "resource";
+ final String[] PARTITIONS = {
+ "resource_0", "resource_1", "resource_2"
+ };
+ final StateModelDefinition STATE_MODEL =
+ new StateModelDefinition(StateModelConfigGenerator.generateConfigForMasterSlave());
+ final int REPLICA_COUNT = 2;
+ final String[] NODES = {
+ "n0", "n1", "n2"
+ };
+
+ // initial state, one node, no mapping
+ List<String> allNodes = Lists.newArrayList(NODES[0]);
+ List<String> liveNodes = Lists.newArrayList(NODES[0]);
+ Map<String, Map<String, String>> currentMapping = Maps.newHashMap();
+ for (String partition : PARTITIONS) {
+ currentMapping.put(partition, new HashMap<String, String>());
+ }
+
+ // make sure that when the first node joins, a single replica is assigned fairly
+ List<String> partitions = ImmutableList.copyOf(PARTITIONS);
+ LinkedHashMap<String, Integer> stateCount =
+ AutoRebalancer.stateCount(STATE_MODEL, liveNodes.size(), REPLICA_COUNT);
+ ZNRecord znRecord =
+ new AutoRebalanceStrategy(RESOURCE_NAME, partitions, stateCount)
+ .computePartitionAssignment(allNodes, liveNodes, currentMapping, null);
+ Map<String, List<String>> preferenceLists = znRecord.getListFields();
+ for (String partition : currentMapping.keySet()) {
+ // make sure these are all MASTER
+ List<String> preferenceList = preferenceLists.get(partition);
+ Assert.assertNotNull(preferenceList, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.size(), 1, "invalid preference list for " + partition);
+ }
+
+ // now assign a replica to the first node in the current mapping, and add a second node
+ allNodes.add(NODES[1]);
+ liveNodes.add(NODES[1]);
+ stateCount = AutoRebalancer.stateCount(STATE_MODEL, liveNodes.size(), REPLICA_COUNT);
+ for (String partition : PARTITIONS) {
+ currentMapping.get(partition).put(NODES[0], "MASTER");
+ }
+ znRecord =
+ new AutoRebalanceStrategy(RESOURCE_NAME, partitions, stateCount)
+ .computePartitionAssignment(allNodes, liveNodes, currentMapping, null);
+ preferenceLists = znRecord.getListFields();
+ for (String partition : currentMapping.keySet()) {
+ List<String> preferenceList = preferenceLists.get(partition);
+ Assert.assertNotNull(preferenceList, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.size(), 2, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.get(0), NODES[0], "invalid preference list for "
+ + partition);
+ Assert.assertEquals(preferenceList.get(1), NODES[1], "invalid preference list for "
+ + partition);
+ }
+
+ // now set the current mapping to reflect this update and make sure that it distributes masters
+ for (String partition : PARTITIONS) {
+ currentMapping.get(partition).put(NODES[1], "SLAVE");
+ }
+ znRecord =
+ new AutoRebalanceStrategy(RESOURCE_NAME, partitions, stateCount)
+ .computePartitionAssignment(allNodes, liveNodes, currentMapping, null);
+ preferenceLists = znRecord.getListFields();
+ Set<String> firstNodes = Sets.newHashSet();
+ for (String partition : currentMapping.keySet()) {
+ List<String> preferenceList = preferenceLists.get(partition);
+ Assert.assertNotNull(preferenceList, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.size(), 2, "invalid preference list for " + partition);
+ firstNodes.add(preferenceList.get(0));
+ }
+ Assert.assertEquals(firstNodes.size(), 2, "masters not evenly distributed");
+
+ // set a mapping corresponding to a valid mapping for 2 nodes, add a third node, check that the
+ // new node is never the most preferred
+ allNodes.add(NODES[2]);
+ liveNodes.add(NODES[2]);
+ stateCount = AutoRebalancer.stateCount(STATE_MODEL, liveNodes.size(), REPLICA_COUNT);
+
+ // recall that the other two partitions are [MASTER, SLAVE], which is fine, just reorder one
+ currentMapping.get(PARTITIONS[1]).put(NODES[0], "SLAVE");
+ currentMapping.get(PARTITIONS[1]).put(NODES[1], "MASTER");
+ znRecord =
+ new AutoRebalanceStrategy(RESOURCE_NAME, partitions, stateCount)
+ .computePartitionAssignment(allNodes, liveNodes, currentMapping, null);
+ preferenceLists = znRecord.getListFields();
+ boolean newNodeUsed = false;
+ for (String partition : currentMapping.keySet()) {
+ List<String> preferenceList = preferenceLists.get(partition);
+ Assert.assertNotNull(preferenceList, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.size(), 2, "invalid preference list for " + partition);
+ if (preferenceList.contains(NODES[2])) {
+ newNodeUsed = true;
+ Assert.assertEquals(preferenceList.get(1), NODES[2],
+ "newly added node not at preference list tail for " + partition);
+ }
+ }
+ Assert.assertTrue(newNodeUsed, "not using " + NODES[2]);
+
+ // now remap this to take the new node into account, should go back to balancing masters, slaves
+ // evenly across all nodes
+ for (String partition : PARTITIONS) {
+ currentMapping.get(partition).clear();
+ }
+ currentMapping.get(PARTITIONS[0]).put(NODES[0], "MASTER");
+ currentMapping.get(PARTITIONS[0]).put(NODES[1], "SLAVE");
+ currentMapping.get(PARTITIONS[1]).put(NODES[1], "MASTER");
+ currentMapping.get(PARTITIONS[1]).put(NODES[2], "SLAVE");
+ currentMapping.get(PARTITIONS[2]).put(NODES[0], "MASTER");
+ currentMapping.get(PARTITIONS[2]).put(NODES[2], "SLAVE");
+ znRecord =
+ new AutoRebalanceStrategy(RESOURCE_NAME, partitions, stateCount)
+ .computePartitionAssignment(allNodes, liveNodes, currentMapping, null);
+ preferenceLists = znRecord.getListFields();
+ firstNodes.clear();
+ Set<String> secondNodes = Sets.newHashSet();
+ for (String partition : currentMapping.keySet()) {
+ List<String> preferenceList = preferenceLists.get(partition);
+ Assert.assertNotNull(preferenceList, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.size(), 2, "invalid preference list for " + partition);
+ firstNodes.add(preferenceList.get(0));
+ secondNodes.add(preferenceList.get(1));
+ }
+ Assert.assertEquals(firstNodes.size(), 3, "masters not distributed evenly");
+ Assert.assertEquals(secondNodes.size(), 3, "slaves not distributed evenly");
+
+ // remove a node now, but use the current mapping with everything balanced just prior
+ liveNodes.remove(0);
+ stateCount = AutoRebalancer.stateCount(STATE_MODEL, liveNodes.size(), REPLICA_COUNT);
+
+ // remove all references of n0 from the mapping, keep everything else in a legal state
+ for (String partition : PARTITIONS) {
+ currentMapping.get(partition).clear();
+ }
+ currentMapping.get(PARTITIONS[0]).put(NODES[1], "MASTER");
+ currentMapping.get(PARTITIONS[1]).put(NODES[1], "MASTER");
+ currentMapping.get(PARTITIONS[1]).put(NODES[2], "SLAVE");
+ currentMapping.get(PARTITIONS[2]).put(NODES[2], "MASTER");
+ znRecord =
+ new AutoRebalanceStrategy(RESOURCE_NAME, partitions, stateCount)
+ .computePartitionAssignment(allNodes, liveNodes, currentMapping, null);
+ preferenceLists = znRecord.getListFields();
+ for (String partition : currentMapping.keySet()) {
+ List<String> preferenceList = preferenceLists.get(partition);
+ Assert.assertNotNull(preferenceList, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.size(), 2, "invalid preference list for " + partition);
+ Map<String, String> stateMap = currentMapping.get(partition);
+ for (String participant : stateMap.keySet()) {
+ Assert.assertTrue(preferenceList.contains(participant), "minimal movement violated for "
+ + partition);
+ }
+ for (String participant : preferenceList) {
+ if (!stateMap.containsKey(participant)) {
+ Assert.assertNotSame(preferenceList.get(0), participant,
+ "newly moved replica should not be master for " + partition);
+ }
+ }
+ }
+
+ // finally, adjust the current mapping to reflect 2 nodes and make sure everything's even again
+ for (String partition : PARTITIONS) {
+ currentMapping.get(partition).clear();
+ }
+ currentMapping.get(PARTITIONS[0]).put(NODES[1], "MASTER");
+ currentMapping.get(PARTITIONS[0]).put(NODES[2], "SLAVE");
+ currentMapping.get(PARTITIONS[1]).put(NODES[1], "SLAVE");
+ currentMapping.get(PARTITIONS[1]).put(NODES[2], "MASTER");
+ currentMapping.get(PARTITIONS[2]).put(NODES[1], "SLAVE");
+ currentMapping.get(PARTITIONS[2]).put(NODES[2], "MASTER");
+ znRecord =
+ new AutoRebalanceStrategy(RESOURCE_NAME, partitions, stateCount)
+ .computePartitionAssignment(allNodes, liveNodes, currentMapping, null);
+ preferenceLists = znRecord.getListFields();
+ firstNodes.clear();
+ for (String partition : currentMapping.keySet()) {
+ List<String> preferenceList = preferenceLists.get(partition);
+ Assert.assertNotNull(preferenceList, "invalid preference list for " + partition);
+ Assert.assertEquals(preferenceList.size(), 2, "invalid preference list for " + partition);
+ firstNodes.add(preferenceList.get(0));
+ }
+ Assert.assertEquals(firstNodes.size(), 2, "masters not evenly distributed");
+ }
+}