HDFS-12354. Ozone: Shuffle container list for datanode BlockDeletingService. Contributed by Yiqun Lin.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/scm/ScmConfigKeys.java

@@ -189,6 +189,8 @@ public final class ScmConfigKeys {
       "ozone.scm.container.provision_batch_size";
   public static final int OZONE_SCM_CONTAINER_PROVISION_BATCH_SIZE_DEFAULT = 5;
 
+  public static final String OZONE_SCM_CONTAINER_DELETION_CHOOSING_POLICY =
+      "ozone.scm.container.deletion-choosing.policy";
 
   /**
    * Don't start processing a pool if we have not had a minimum number of

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/impl/ContainerStatus.java

@@ -0,0 +1,67 @@
+/**
+ * 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.ozone.container.common.impl;
+
+import org.apache.hadoop.ozone.container.common.helpers.ContainerData;
+
+/**
+ * This is an immutable class that represents the state of a container. if the
+ * container reading encountered an error when we boot up we will post that
+ * info to a recovery queue and keep the info in the containerMap.
+ * <p/>
+ * if and when the issue is fixed, the expectation is that this entry will be
+ * deleted by the recovery thread from the containerMap and will insert entry
+ * instead of modifying this class.
+ */
+public class ContainerStatus {
+  private final ContainerData containerData;
+  private final boolean active;
+
+  /**
+   * Creates a Container Status class.
+   *
+   * @param containerData - ContainerData.
+   * @param active - Active or not active.
+   */
+  ContainerStatus(ContainerData containerData, boolean active) {
+    this.containerData = containerData;
+    this.active = active;
+  }
+
+  /**
+   * Returns container if it is active. It is not active if we have had an
+   * error and we are waiting for the background threads to fix the issue.
+   *
+   * @return ContainerData.
+   */
+  public ContainerData getContainer() {
+    if (active) {
+      return containerData;
+    }
+    return null;
+  }
+
+  /**
+   * Indicates if a container is Active.
+   *
+   * @return true if it is active.
+   */
+  public boolean isActive() {
+    return active;
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/impl/RandomContainerDeletionChoosingPolicy.java

@@ -0,0 +1,60 @@
+/**
+ * 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.ozone.container.common.impl;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.hadoop.hdfs.DFSUtil;
+import org.apache.hadoop.ozone.container.common.helpers.ContainerData;
+import org.apache.hadoop.ozone.container.common.interfaces.ContainerDeletionChoosingPolicy;
+import org.apache.hadoop.scm.container.common.helpers.StorageContainerException;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * Randomly choosing containers for block deletion.
+ */
+public class RandomContainerDeletionChoosingPolicy
+    implements ContainerDeletionChoosingPolicy {
+
+  @Override
+  public List<ContainerData> chooseContainerForBlockDeletion(int count,
+      Map<String, ContainerStatus> candidateContainers)
+      throws StorageContainerException {
+    Preconditions.checkNotNull(candidateContainers,
+        "Internal assertion: candidate containers cannot be null");
+
+    int currentCount = 0;
+    List<ContainerData> result = new LinkedList<>();
+    ContainerStatus[] values = new ContainerStatus[candidateContainers.size()];
+    // to get a shuffle list
+    for (ContainerStatus entry : DFSUtil.shuffle(
+        candidateContainers.values().toArray(values))) {
+      if (currentCount < count) {
+        result.add(entry.getContainer());
+        currentCount++;
+      } else {
+        break;
+      }
+    }
+
+    return result;
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/interfaces/ContainerDeletionChoosingPolicy.java

@@ -0,0 +1,45 @@
+/**
+ * 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.ozone.container.common.interfaces;
+
+import java.util.List;
+import java.util.Map;
+
+import org.apache.hadoop.ozone.container.common.helpers.ContainerData;
+import org.apache.hadoop.ozone.container.common.impl.ContainerStatus;
+import org.apache.hadoop.scm.container.common.helpers.StorageContainerException;
+
+/**
+ * This interface is used for choosing desired containers for
+ * block deletion.
+ */
+public interface ContainerDeletionChoosingPolicy {
+
+  /**
+   * Chooses desired containers for block deletion.
+   * @param count
+   *          how many to return
+   * @param candidateContainers
+   *          candidate containers collection
+   * @return container data list
+   * @throws StorageContainerException
+   */
+  List<ContainerData> chooseContainerForBlockDeletion(int count,
+      Map<String, ContainerStatus> candidateContainers)
+      throws StorageContainerException;
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/interfaces/ContainerManager.java

@@ -95,6 +95,15 @@ void listContainer(String prefix, long count, String prevKey,
                      List<ContainerData> data)
       throws StorageContainerException;
 
+  /**
+   * Choose containers for block deletion.
+   *
+   * @param count   - how many to return
+   * @throws StorageContainerException
+   */
+  List<ContainerData> chooseContainerForBlockDeletion(int count)
+      throws StorageContainerException;
+
   /**
    * Get metadata about a specific container.
    *

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/background/BlockDeletingService.java

@@ -102,8 +102,8 @@ public BackgroundTaskQueue getTasks() {
       // We at most list a number of containers a time,
       // in case there are too many containers and start too many workers.
       // We must ensure there is no empty container in this result.
-      containerManager.listContainer(null, containerLimitPerInterval,
+      containers = containerManager.chooseContainerForBlockDeletion(
-          null, containers);
+          containerLimitPerInterval);
 
       // TODO
       // in case we always fetch a few same containers,

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/ozone-default.xml

@@ -416,6 +416,21 @@
     </description>
   </property>
 
+  <property>
+    <name>ozone.scm.container.deletion-choosing.policy</name>
+    <value>org.apache.hadoop.ozone.container.common.impl.RandomContainerDeletionChoosingPolicy</value>
+    <description>
+      The policy used for choosing desire containers for block deletion.
+      Datanode selects a number of containers to process block deletion
+      in a certain interval defined by ozone.block.deleting.service.interval.ms,
+      the number of containers to process in each interval is defined
+      by ozone.block.deleting.container.limit.per.interval. This property
+      is used to configure the policy applied while selecting containers,
+      org.apache.hadoop.ozone.container.common.impl.RandomContainerDeletionChoosingPolicy
+      implements a simply random policy that to return a random list of containers.
+    </description>
+  </property>
+
   <property>
     <name>dfs.container.ipc</name>
     <value>50011</value>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/ozone/container/common/impl/TestContainerDeletionChoosingPolicy.java

@@ -0,0 +1,108 @@
+/**
+ * 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.ozone.container.common.impl;
+
+import static org.apache.hadoop.ozone.container.ContainerTestHelper.createSingleNodePipeline;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.hadoop.hdfs.server.datanode.StorageLocation;
+import org.apache.hadoop.ozone.OzoneConfigKeys;
+import org.apache.hadoop.ozone.OzoneConfiguration;
+import org.apache.hadoop.ozone.container.common.helpers.ContainerData;
+import org.apache.hadoop.ozone.web.utils.OzoneUtils;
+import org.apache.hadoop.scm.ScmConfigKeys;
+import org.apache.hadoop.test.GenericTestUtils;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * The class for testing container deletion choosing policy.
+ */
+public class TestContainerDeletionChoosingPolicy {
+  private static String path;
+  private static ContainerManagerImpl containerManager;
+  private static OzoneConfiguration conf;
+
+  @BeforeClass
+  public static void init() throws Throwable {
+    conf = new OzoneConfiguration();
+    path = GenericTestUtils
+        .getTempPath(TestContainerDeletionChoosingPolicy.class.getSimpleName());
+    path += conf.getTrimmed(OzoneConfigKeys.OZONE_LOCALSTORAGE_ROOT,
+        OzoneConfigKeys.OZONE_LOCALSTORAGE_ROOT_DEFAULT);
+    conf.set(OzoneConfigKeys.OZONE_LOCALSTORAGE_ROOT, path);
+  }
+
+  @AfterClass
+  public static void shutdown() throws IOException {
+    FileUtils.deleteDirectory(new File(path));
+  }
+
+  @Test
+  public void testRandomChoosingPolicy() throws IOException {
+    File containerDir = new File(path);
+    if (containerDir.exists()) {
+      FileUtils.deleteDirectory(new File(path));
+    }
+    Assert.assertTrue(containerDir.mkdirs());
+
+    conf.set(ScmConfigKeys.OZONE_SCM_CONTAINER_DELETION_CHOOSING_POLICY,
+        RandomContainerDeletionChoosingPolicy.class.getName());
+    List<StorageLocation> pathLists = new LinkedList<>();
+    pathLists.add(StorageLocation.parse(containerDir.getAbsolutePath()));
+    containerManager = new ContainerManagerImpl();
+    containerManager.init(conf, pathLists);
+
+    int numContainers = 10;
+    for (int i = 0; i < numContainers; i++) {
+      String containerName = OzoneUtils.getRequestID();
+      ContainerData data = new ContainerData(containerName);
+      containerManager.createContainer(createSingleNodePipeline(containerName),
+          data);
+      Assert.assertTrue(
+          containerManager.getContainerMap().containsKey(containerName));
+    }
+
+    List<ContainerData> result0 = containerManager
+        .chooseContainerForBlockDeletion(5);
+    Assert.assertEquals(5, result0.size());
+
+    // test random choosing
+    List<ContainerData> result1 = containerManager
+        .chooseContainerForBlockDeletion(numContainers);
+    List<ContainerData> result2 = containerManager
+        .chooseContainerForBlockDeletion(numContainers);
+
+    boolean hasShuffled = false;
+    for (int i = 0; i < numContainers; i++) {
+      if (!result1.get(i).getContainerName()
+          .equals(result2.get(i).getContainerName())) {
+        hasShuffled = true;
+        break;
+      }
+    }
+    Assert.assertTrue("Chosen container results were same", hasShuffled);
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/ozone/container/common/impl/TestContainerPersistence.java

@@ -170,7 +170,7 @@ public void testCreateContainer() throws Exception {
         data);
     Assert.assertTrue(containerManager.getContainerMap()
         .containsKey(containerName));
-    ContainerManagerImpl.ContainerStatus status = containerManager
+    ContainerStatus status = containerManager
         .getContainerMap().get(containerName);
 
     Assert.assertTrue(status.isActive());