/**
* 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.hdfs.server.datanode.fsdataset;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_AVAILABLE_SPACE_VOLUME_CHOOSING_POLICY_BALANCED_SPACE_THRESHOLD_KEY;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_AVAILABLE_SPACE_VOLUME_CHOOSING_POLICY_BALANCED_SPACE_PREFERENCE_FRACTION_KEY;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.test.GenericTestUtils;
import org.apache.hadoop.util.ReflectionUtils;
import org.junit.Assert;
import org.junit.Test;
import org.mockito.Mockito;
public class TestAvailableSpaceVolumeChoosingPolicy {
private static final int RANDOMIZED_ITERATIONS = 10000;
private static final float RANDOMIZED_ERROR_PERCENT = 0.05f;
private static final long RANDOMIZED_ALLOWED_ERROR = (long) (RANDOMIZED_ERROR_PERCENT * RANDOMIZED_ITERATIONS);
private static void initPolicy(VolumeChoosingPolicy<FsVolumeSpi> policy,
float preferencePercent) {
Configuration conf = new Configuration();
// Set the threshold to consider volumes imbalanced to 1MB
conf.setLong(
DFS_DATANODE_AVAILABLE_SPACE_VOLUME_CHOOSING_POLICY_BALANCED_SPACE_THRESHOLD_KEY,
1024 * 1024); // 1MB
conf.setFloat(
DFS_DATANODE_AVAILABLE_SPACE_VOLUME_CHOOSING_POLICY_BALANCED_SPACE_PREFERENCE_FRACTION_KEY,
preferencePercent);
((Configurable) policy).setConf(conf);
}
// Test the Round-Robin block-volume fallback path when all volumes are within
// the threshold.
@Test(timeout=60000)
public void testRR() throws Exception {
@SuppressWarnings("unchecked")
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy =
ReflectionUtils.newInstance(AvailableSpaceVolumeChoosingPolicy.class, null);
initPolicy(policy, 1.0f);
TestRoundRobinVolumeChoosingPolicy.testRR(policy);
}
// ChooseVolume should throw DiskOutOfSpaceException
// with volume and block sizes in exception message.
@Test(timeout=60000)
public void testRRPolicyExceptionMessage() throws Exception {
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy
= new AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi>();
initPolicy(policy, 1.0f);
TestRoundRobinVolumeChoosingPolicy.testRRPolicyExceptionMessage(policy);
}
@Test(timeout=60000)
public void testTwoUnbalancedVolumes() throws Exception {
@SuppressWarnings("unchecked")
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy =
ReflectionUtils.newInstance(AvailableSpaceVolumeChoosingPolicy.class, null);
initPolicy(policy, 1.0f);
List<FsVolumeSpi> volumes = new ArrayList<FsVolumeSpi>();
// First volume with 1MB free space
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(0).getAvailable()).thenReturn(1024L * 1024L);
// Second volume with 3MB free space, which is a difference of 2MB, more
// than the threshold of 1MB.
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(1).getAvailable()).thenReturn(1024L * 1024L * 3);
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
}
@Test(timeout=60000)
public void testThreeUnbalancedVolumes() throws Exception {
@SuppressWarnings("unchecked")
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy =
ReflectionUtils.newInstance(AvailableSpaceVolumeChoosingPolicy.class, null);
List<FsVolumeSpi> volumes = new ArrayList<FsVolumeSpi>();
// First volume with 1MB free space
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(0).getAvailable()).thenReturn(1024L * 1024L);
// Second volume with 3MB free space, which is a difference of 2MB, more
// than the threshold of 1MB.
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(1).getAvailable()).thenReturn(1024L * 1024L * 3);
// Third volume, again with 3MB free space.
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(2).getAvailable()).thenReturn(1024L * 1024L * 3);
// We should alternate assigning between the two volumes with a lot of free
// space.
initPolicy(policy, 1.0f);
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(2), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(2), policy.chooseVolume(volumes, 100));
// All writes should be assigned to the volume with the least free space.
initPolicy(policy, 0.0f);
Assert.assertEquals(volumes.get(0), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(0), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(0), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(0), policy.chooseVolume(volumes, 100));
}
@Test(timeout=60000)
public void testFourUnbalancedVolumes() throws Exception {
@SuppressWarnings("unchecked")
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy =
ReflectionUtils.newInstance(AvailableSpaceVolumeChoosingPolicy.class, null);
List<FsVolumeSpi> volumes = new ArrayList<FsVolumeSpi>();
// First volume with 1MB free space
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(0).getAvailable()).thenReturn(1024L * 1024L);
// Second volume with 1MB + 1 byte free space
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(1).getAvailable()).thenReturn(1024L * 1024L + 1);
// Third volume with 3MB free space, which is a difference of 2MB, more
// than the threshold of 1MB.
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(2).getAvailable()).thenReturn(1024L * 1024L * 3);
// Fourth volume, again with 3MB free space.
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(3).getAvailable()).thenReturn(1024L * 1024L * 3);
// We should alternate assigning between the two volumes with a lot of free
// space.
initPolicy(policy, 1.0f);
Assert.assertEquals(volumes.get(2), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(3), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(2), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(3), policy.chooseVolume(volumes, 100));
// We should alternate assigning between the two volumes with less free
// space.
initPolicy(policy, 0.0f);
Assert.assertEquals(volumes.get(0), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(0), policy.chooseVolume(volumes, 100));
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
}
@Test(timeout=60000)
public void testNotEnoughSpaceOnSelectedVolume() throws Exception {
@SuppressWarnings("unchecked")
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy =
ReflectionUtils.newInstance(AvailableSpaceVolumeChoosingPolicy.class, null);
List<FsVolumeSpi> volumes = new ArrayList<FsVolumeSpi>();
// First volume with 1MB free space
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(0).getAvailable()).thenReturn(1024L * 1024L);
// Second volume with 3MB free space, which is a difference of 2MB, more
// than the threshold of 1MB.
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(1).getAvailable()).thenReturn(1024L * 1024L * 3);
// All writes should be assigned to the volume with the least free space.
// However, if the volume with the least free space doesn't have enough
// space to accept the replica size, and another volume does have enough
// free space, that should be chosen instead.
initPolicy(policy, 0.0f);
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 1024L * 1024L * 2));
}
@Test(timeout=60000)
public void testAvailableSpaceChanges() throws Exception {
@SuppressWarnings("unchecked")
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy =
ReflectionUtils.newInstance(AvailableSpaceVolumeChoosingPolicy.class, null);
initPolicy(policy, 1.0f);
List<FsVolumeSpi> volumes = new ArrayList<FsVolumeSpi>();
// First volume with 1MB free space
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(0).getAvailable()).thenReturn(1024L * 1024L);
// Second volume with 3MB free space, which is a difference of 2MB, more
// than the threshold of 1MB.
volumes.add(Mockito.mock(FsVolumeSpi.class));
Mockito.when(volumes.get(1).getAvailable())
.thenReturn(1024L * 1024L * 3)
.thenReturn(1024L * 1024L * 3)
.thenReturn(1024L * 1024L * 3)
.thenReturn(1024L * 1024L * 1); // After the third check, return 1MB.
// Should still be able to get a volume for the replica even though the
// available space on the second volume changed.
Assert.assertEquals(volumes.get(1), policy.chooseVolume(volumes, 100));
}
@Test(timeout=60000)
public void randomizedTest1() throws Exception {
doRandomizedTest(0.75f, 1, 1);
}
@Test(timeout=60000)
public void randomizedTest2() throws Exception {
doRandomizedTest(0.75f, 5, 1);
}
@Test(timeout=60000)
public void randomizedTest3() throws Exception {
doRandomizedTest(0.75f, 1, 5);
}
@Test(timeout=60000)
public void randomizedTest4() throws Exception {
doRandomizedTest(0.90f, 5, 1);
}
/*
* Ensure that we randomly select the lesser-used volumes with appropriate
* frequency.
*/
public void doRandomizedTest(float preferencePercent, int lowSpaceVolumes,
int highSpaceVolumes) throws Exception {
@SuppressWarnings("unchecked")
final AvailableSpaceVolumeChoosingPolicy<FsVolumeSpi> policy =
ReflectionUtils.newInstance(AvailableSpaceVolumeChoosingPolicy.class, null);
List<FsVolumeSpi> volumes = new ArrayList<FsVolumeSpi>();
// Volumes with 1MB free space
for (int i = 0; i < lowSpaceVolumes; i++) {
FsVolumeSpi volume = Mockito.mock(FsVolumeSpi.class);
Mockito.when(volume.getAvailable()).thenReturn(1024L * 1024L);
volumes.add(volume);
}
// Volumes with 3MB free space
for (int i = 0; i < highSpaceVolumes; i++) {
FsVolumeSpi volume = Mockito.mock(FsVolumeSpi.class);
Mockito.when(volume.getAvailable()).thenReturn(1024L * 1024L * 3);
volumes.add(volume);
}
initPolicy(policy, preferencePercent);
long lowAvailableSpaceVolumeSelected = 0;
long highAvailableSpaceVolumeSelected = 0;
for (int i = 0; i < RANDOMIZED_ITERATIONS; i++) {
FsVolumeSpi volume = policy.chooseVolume(volumes, 100);
for (int j = 0; j < volumes.size(); j++) {
// Note how many times the first low available volume was selected
if (volume == volumes.get(j) && j == 0) {
lowAvailableSpaceVolumeSelected++;
}
// Note how many times the first high available volume was selected
if (volume == volumes.get(j) && j == lowSpaceVolumes) {
highAvailableSpaceVolumeSelected++;
break;
}
}
}
// Calculate the expected ratio of how often low available space volumes
// were selected vs. high available space volumes.
float expectedSelectionRatio = preferencePercent / (1 - preferencePercent);
GenericTestUtils.assertValueNear(
(long)(lowAvailableSpaceVolumeSelected * expectedSelectionRatio),
highAvailableSpaceVolumeSelected,
RANDOMIZED_ALLOWED_ERROR);
}
}