HDFS-11154. Block Storage: store server state to persistent storage. Contributed by Chen Liang

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/cblock/CBlockConfigKeys.java

@@ -57,6 +57,12 @@ public final class CBlockConfigKeys {
       "dfs.storage.service.handler.count";
   public static final int DFS_CBLOCK_SERVICERPC_HANDLER_COUNT_DEFAULT = 10;
 
+  public static final String DFS_CBLOCK_SERVICE_LEVELDB_PATH_KEY =
+      "dfs.cblock.service.leveldb.path";
+  //TODO : find a better place
+  public static final String DFS_CBLOCK_SERVICE_LEVELDB_PATH_DEFAULT =
+      "/tmp/cblock_levelDB.dat";
+
   private CBlockConfigKeys() {
 
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/cblock/CBlockManager.java

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.cblock;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.protobuf.BlockingService;
 import org.apache.hadoop.cblock.meta.VolumeDescriptor;
 import org.apache.hadoop.cblock.meta.VolumeInfo;
@@ -31,16 +32,22 @@ import org.apache.hadoop.cblock.protocolPB.CBlockServiceProtocolPB;
 import org.apache.hadoop.cblock.protocolPB.CBlockServiceProtocolServerSideTranslatorPB;
 import org.apache.hadoop.cblock.storage.IStorageClient;
 import org.apache.hadoop.cblock.storage.StorageManager;
+import org.apache.hadoop.cblock.util.KeyUtil;
 import org.apache.hadoop.ipc.ProtobufRpcEngine;
 import org.apache.hadoop.ipc.RPC;
 import org.apache.hadoop.net.NetUtils;
+import org.apache.hadoop.utils.LevelDBStore;
+import org.iq80.leveldb.DBIterator;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.File;
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
 import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_JSCSIRPC_ADDRESS_DEFAULT;
 import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_JSCSIRPC_ADDRESS_KEY;
@@ -50,6 +57,8 @@ import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_SERVICERPC_AD
 import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_SERVICERPC_BIND_HOST_KEY;
 import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_SERVICERPC_HANDLER_COUNT_DEFAULT;
 import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_SERVICERPC_HANDLER_COUNT_KEY;
+import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_SERVICE_LEVELDB_PATH_DEFAULT;
+import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_SERVICE_LEVELDB_PATH_KEY;
 
 /**
  * The main entry point of CBlock operations, ALL the CBlock operations
@@ -74,10 +83,21 @@ public class CBlockManager implements CBlockServiceProtocol,
 
   private final StorageManager storageManager;
 
+  private final LevelDBStore levelDBStore;
+  private final String dbPath;
+
+  private Charset encoding = Charset.forName("UTF-8");
+
   public CBlockManager(CBlockConfiguration conf, IStorageClient storageClient
   ) throws IOException {
     storageManager = new StorageManager(storageClient);
 
+    dbPath = conf.getTrimmed(DFS_CBLOCK_SERVICE_LEVELDB_PATH_KEY,
+        DFS_CBLOCK_SERVICE_LEVELDB_PATH_DEFAULT);
+    levelDBStore = new LevelDBStore(new File(dbPath), true);
+    LOG.info("Try to load exising volume information");
+    readFromPersistentStore();
+
     RPC.setProtocolEngine(conf, CBlockServiceProtocolPB.class,
         ProtobufRpcEngine.class);
     RPC.setProtocolEngine(conf, CBlockClientServerProtocolPB.class,
@@ -182,13 +202,13 @@ public class CBlockManager implements CBlockServiceProtocol,
   }
 
   @Override
-  public MountVolumeResponse mountVolume(
+  public synchronized MountVolumeResponse mountVolume(
       String userName, String volumeName) throws IOException {
     return storageManager.isVolumeValid(userName, volumeName);
   }
 
   @Override
-  public void createVolume(String userName, String volumeName,
+  public synchronized void createVolume(String userName, String volumeName,
       long volumeSize, int blockSize) throws IOException {
     LOG.info("Create volume received: userName: {} volumeName: {} " +
         "volumeSize: {} blockSize: {}", userName, volumeName,
@@ -205,25 +225,82 @@ public class CBlockManager implements CBlockServiceProtocol,
     if (volume == null) {
       throw new IOException("Volume creation failed!");
     }
+    String volumeKey = KeyUtil.getVolumeKey(userName, volumeName);
+    writeToPersistentStore(volumeKey.getBytes(encoding),
+        volume.toProtobuf().toByteArray());
   }
 
   @Override
-  public void deleteVolume(String userName,
+  public synchronized void deleteVolume(String userName,
       String volumeName, boolean force) throws IOException {
-    LOG.info("Delete volume received: volume:" + volumeName
-        + " force?:" + force);
+    LOG.info("Delete volume received: volume: {} {} ", volumeName, force);
     storageManager.deleteVolume(userName, volumeName, force);
+    // being here means volume is successfully deleted now
+    String volumeKey = KeyUtil.getVolumeKey(userName, volumeName);
+    removeFromPersistentStore(volumeKey.getBytes(encoding));
+  }
+
+  // No need to synchronize on the following three methods, since write and
+  // remove's caller are synchronized. read's caller is the constructor and
+  // no other method call can happen at that time.
+  @VisibleForTesting
+  public void writeToPersistentStore(byte[] key, byte[] value) {
+    levelDBStore.put(key, value);
+  }
+
+  @VisibleForTesting
+  public void removeFromPersistentStore(byte[] key) {
+    levelDBStore.delete(key);
+  }
+
+  public void readFromPersistentStore() {
+    DBIterator iter = levelDBStore.getIterator();
+    iter.seekToFirst();
+    while (iter.hasNext()) {
+      Map.Entry<byte[], byte[]> entry = iter.next();
+      String volumeKey = new String(entry.getKey(), encoding);
+      try {
+        VolumeDescriptor volumeDescriptor =
+            VolumeDescriptor.fromProtobuf(entry.getValue());
+        storageManager.addVolume(volumeDescriptor);
+      } catch (IOException e) {
+        LOG.error("Loading volume " + volumeKey + " error " + e);
+      }
+    }
   }
 
   @Override
-  public VolumeInfo infoVolume(String userName, String volumeName
+  public synchronized VolumeInfo infoVolume(String userName, String volumeName
   ) throws IOException {
     LOG.info("Info volume received: volume: {}", volumeName);
     return storageManager.infoVolume(userName, volumeName);
   }
 
+  @VisibleForTesting
+  public synchronized List<VolumeDescriptor> getAllVolumes() {
+    return storageManager.getAllVolume(null);
+  }
+
+  public synchronized void close() {
+    try {
+      levelDBStore.close();
+    } catch (IOException e) {
+      LOG.error("Error when closing levelDB " + e);
+    }
+  }
+
+  public synchronized void clean() {
+    try {
+      levelDBStore.close();
+      levelDBStore.destroy();
+    } catch (IOException e) {
+      LOG.error("Error when deleting levelDB " + e);
+    }
+  }
+
   @Override
-  public List<VolumeInfo> listVolume(String userName) throws IOException {
+  public synchronized List<VolumeInfo> listVolume(String userName)
+      throws IOException {
     ArrayList<VolumeInfo> response = new ArrayList<>();
     List<VolumeDescriptor> allVolumes =
         storageManager.getAllVolume(userName);

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/cblock/meta/ContainerDescriptor.java

@@ -17,6 +17,9 @@
  */
 package org.apache.hadoop.cblock.meta;
 
+import com.google.protobuf.InvalidProtocolBufferException;
+import org.apache.hadoop.cblock.protocol.proto.CBlockClientServerProtocolProtos;
+
 /**
  *
  * The internal representation of a container maintained by CBlock server.
@@ -29,7 +32,7 @@ package org.apache.hadoop.cblock.meta;
 public class ContainerDescriptor {
   private final String containerID;
   // the index of this container with in a volume
-  // on creation, there is no way to know the index of the container
+  // on creation, there may be no way to know the index of the container
   // as it is a volume specific information
   private int containerIndex;
 
@@ -37,6 +40,11 @@ public class ContainerDescriptor {
     this.containerID = containerID;
   }
 
+  public ContainerDescriptor(String containerID, int containerIndex) {
+    this.containerID = containerID;
+    this.containerIndex = containerIndex;
+  }
+
   public void setContainerIndex(int idx) {
     this.containerIndex = idx;
   }
@@ -52,4 +60,35 @@ public class ContainerDescriptor {
   public long getUtilization() {
     return 0;
   }
+
+  public CBlockClientServerProtocolProtos.ContainerIDProto toProtobuf() {
+    CBlockClientServerProtocolProtos.ContainerIDProto.Builder builder =
+            CBlockClientServerProtocolProtos.ContainerIDProto.newBuilder();
+    builder.setContainerID(containerID);
+    builder.setIndex(containerIndex);
+    return builder.build();
+  }
+
+  public static ContainerDescriptor fromProtobuf(byte[] data)
+      throws InvalidProtocolBufferException {
+    CBlockClientServerProtocolProtos.ContainerIDProto id =
+            CBlockClientServerProtocolProtos.ContainerIDProto.parseFrom(data);
+    return new ContainerDescriptor(id.getContainerID(),
+            (int)id.getIndex());
+  }
+
+  @Override
+  public int hashCode() {
+    return containerID.hashCode()*37 + containerIndex;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o != null && o instanceof ContainerDescriptor) {
+      ContainerDescriptor other = (ContainerDescriptor)o;
+      return containerID.equals(other.containerID) &&
+          containerIndex == other.containerIndex;
+    }
+    return false;
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/cblock/meta/VolumeDescriptor.java

@@ -17,10 +17,13 @@
  */
 package org.apache.hadoop.cblock.meta;
 
+import com.google.protobuf.InvalidProtocolBufferException;
+import org.apache.hadoop.cblock.protocol.proto.CBlockClientServerProtocolProtos;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
@@ -162,4 +165,90 @@ public class VolumeDescriptor {
     string += "containerIdsWithObject:" + containerMap.keySet();
     return string;
   }
+
+  public CBlockClientServerProtocolProtos.MountVolumeResponseProto
+      toProtobuf() {
+    CBlockClientServerProtocolProtos.MountVolumeResponseProto.Builder volume =
+        CBlockClientServerProtocolProtos.MountVolumeResponseProto.newBuilder();
+    volume.setIsValid(true);
+    volume.setVolumeName(volumeName);
+    volume.setUserName(userName);
+    volume.setVolumeSize(volumeSize);
+    volume.setBlockSize(blockSize);
+    for (String containerIDString : containerIdOrdered) {
+      ContainerDescriptor containerDescriptor = containerMap.get(
+          containerIDString);
+      volume.addAllContainerIDs(containerDescriptor.toProtobuf());
+    }
+    return volume.build();
+  }
+
+  public static VolumeDescriptor fromProtobuf(byte[] data)
+      throws InvalidProtocolBufferException {
+    CBlockClientServerProtocolProtos.MountVolumeResponseProto volume =
+        CBlockClientServerProtocolProtos.MountVolumeResponseProto
+            .parseFrom(data);
+    String userName = volume.getUserName();
+    String volumeName = volume.getVolumeName();
+    long volumeSize = volume.getVolumeSize();
+    int blockSize = volume.getBlockSize();
+    VolumeDescriptor volumeDescriptor = new VolumeDescriptor(userName,
+        volumeName, volumeSize, blockSize);
+    List<CBlockClientServerProtocolProtos.ContainerIDProto> containers
+        = volume.getAllContainerIDsList();
+
+    String[] containerOrdering = new String[containers.size()];
+
+    for (CBlockClientServerProtocolProtos.ContainerIDProto containerProto :
+        containers) {
+      ContainerDescriptor containerDescriptor = new ContainerDescriptor(
+          containerProto.getContainerID(),
+          (int)containerProto.getIndex());
+      volumeDescriptor.addContainer(containerDescriptor);
+      containerOrdering[containerDescriptor.getContainerIndex()] =
+          containerDescriptor.getContainerID();
+    }
+    volumeDescriptor.setContainerIDs(
+        new ArrayList<>(Arrays.asList(containerOrdering)));
+    return volumeDescriptor;
+  }
+
+  @Override
+  public int hashCode() {
+    return userName.hashCode()*37 + volumeName.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o != null && o instanceof VolumeDescriptor) {
+      VolumeDescriptor other = (VolumeDescriptor)o;
+      if (!userName.equals(other.getUserName()) ||
+          !volumeName.equals(other.getVolumeName()) ||
+          volumeSize != other.getVolumeSize() ||
+          blockSize != other.getBlockSize()) {
+        return false;
+      }
+      if (containerIdOrdered.size() != other.containerIdOrdered.size() ||
+          containerMap.size() != other.containerMap.size()) {
+        return false;
+      }
+      for (int i = 0; i<containerIdOrdered.size(); i++) {
+        if (!containerIdOrdered.get(i).equals(
+            other.containerIdOrdered.get(i))) {
+          return false;
+        }
+      }
+      for (String containerKey : containerMap.keySet()) {
+        if (!other.containerMap.containsKey(containerKey)) {
+          return false;
+        }
+        if (!containerMap.get(containerKey).equals(
+            other.containerMap.get(containerKey))) {
+          return false;
+        }
+      }
+      return true;
+    }
+    return false;
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/cblock/util/KeyUtil.java

@@ -0,0 +1,32 @@
+/*
+ * 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.cblock.util;
+
+/**
+ * A simply class that generates key mappings. (e.g. from (userName, volumeName)
+ * pair to a single string volumeKey.
+ */
+public final class KeyUtil {
+  public static String getVolumeKey(String userName, String volumeName) {
+    return userName + ":" + volumeName;
+  }
+
+  private KeyUtil() {
+
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/cblock/util/package-info.java

@@ -0,0 +1,18 @@
+/**
+ * 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.cblock.util;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/helpers/ContainerUtils.java

@@ -24,7 +24,7 @@ import org.apache.hadoop.fs.FileAlreadyExistsException;
 import org.apache.hadoop.hdfs.ozone.protocol.proto.ContainerProtos;
 import org.apache.hadoop.ozone.OzoneConsts;
 import org.apache.hadoop.ozone.container.common.impl.ContainerManagerImpl;
-import org.apache.hadoop.ozone.container.common.utils.LevelDBStore;
+import org.apache.hadoop.utils.LevelDBStore;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/helpers/KeyUtils.java

@@ -21,7 +21,7 @@ import com.google.common.base.Preconditions;
 import org.apache.hadoop.hdfs.ozone.protocol.proto.ContainerProtos;
 import org.apache.hadoop.ozone.container.common.impl.KeyManagerImpl;
 import org.apache.hadoop.ozone.container.common.utils.ContainerCache;
-import org.apache.hadoop.ozone.container.common.utils.LevelDBStore;
+import org.apache.hadoop.utils.LevelDBStore;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 

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

@@ -29,7 +29,7 @@ import org.apache.hadoop.scm.container.common.helpers.Pipeline;
 import org.apache.hadoop.ozone.container.common.interfaces.ContainerManager;
 import org.apache.hadoop.ozone.container.common.interfaces.KeyManager;
 import org.apache.hadoop.ozone.container.common.utils.ContainerCache;
-import org.apache.hadoop.ozone.container.common.utils.LevelDBStore;
+import org.apache.hadoop.utils.LevelDBStore;
 
 import java.io.IOException;
 import java.util.List;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/utils/ContainerCache.java

@@ -22,6 +22,7 @@ import com.google.common.base.Preconditions;
 import org.apache.commons.collections.map.LRUMap;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.utils.LevelDBStore;
 
 import java.io.IOException;
 import java.util.concurrent.locks.Lock;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/scm/container/ContainerMapping.java

@@ -22,9 +22,9 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.ozone.protocol.proto.ContainerProtos;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.ozone.OzoneConfigKeys;
-import org.apache.hadoop.ozone.container.common.utils.LevelDBStore;
 import org.apache.hadoop.ozone.scm.node.NodeManager;
 import org.apache.hadoop.scm.container.common.helpers.Pipeline;
+import org.apache.hadoop.utils.LevelDBStore;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/web/localstorage/OzoneMetadataManager.java

@@ -23,7 +23,7 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.LengthInputStream;
 import org.apache.hadoop.ozone.OzoneConfigKeys;
 import org.apache.hadoop.ozone.OzoneConsts;
-import org.apache.hadoop.ozone.container.common.utils.LevelDBStore;
+import org.apache.hadoop.utils.LevelDBStore;
 import org.apache.hadoop.ozone.web.exceptions.ErrorTable;
 import org.apache.hadoop.ozone.web.exceptions.OzoneException;
 import org.apache.hadoop.ozone.web.handlers.BucketArgs;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/container/common/utils/LevelDBStore.java → hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/utils/LevelDBStore.java

@@ -16,7 +16,7 @@
  *  limitations under the License.
  */
 
-package org.apache.hadoop.ozone.container.common.utils;
+package org.apache.hadoop.utils;
 
 import org.fusesource.leveldbjni.JniDBFactory;
 import org.iq80.leveldb.DB;
@@ -33,6 +33,7 @@ import java.io.IOException;
 public class LevelDBStore {
   private DB db;
   private final File dbFile;
+  private final Options dbOptions;
 
   /**
    * Opens a DB file.
@@ -43,9 +44,9 @@ public class LevelDBStore {
    */
   public LevelDBStore(File dbPath, boolean createIfMissing) throws
       IOException {
-    Options options = new Options();
-    options.createIfMissing(createIfMissing);
-    db = JniDBFactory.factory.open(dbPath, options);
+    dbOptions = new Options();
+    dbOptions.createIfMissing(createIfMissing);
+    db = JniDBFactory.factory.open(dbPath, dbOptions);
     if (db == null) {
       throw new IOException("Db is null");
     }
@@ -60,6 +61,7 @@ public class LevelDBStore {
    */
   public LevelDBStore(File dbPath, Options options)
       throws IOException {
+    dbOptions = options;
     db = JniDBFactory.factory.open(dbPath, options);
     if (db == null) {
       throw new IOException("Db is null");
@@ -140,4 +142,16 @@ public class LevelDBStore {
     return db;
   }
 
+  /**
+   * Returns an iterator on all the key-value pairs in the DB.
+   * @return an iterator on DB entries.
+   */
+  public DBIterator getIterator() {
+    return db.iterator();
+  }
+
+
+  public void destroy() throws IOException {
+    JniDBFactory.factory.destroy(dbFile, dbOptions);
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/utils/package-info.java

@@ -0,0 +1,18 @@
+/**
+ * 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.utils;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/cblock/TestCBlockServerPersistence.java

@@ -0,0 +1,103 @@
+/*
+ * 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.cblock;
+
+import org.apache.hadoop.cblock.meta.VolumeDescriptor;
+import org.apache.hadoop.cblock.storage.IStorageClient;
+import org.apache.hadoop.cblock.util.MockStorageClient;
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.apache.hadoop.cblock.CBlockConfigKeys.DFS_CBLOCK_SERVICE_LEVELDB_PATH_KEY;
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Test the CBlock server state is maintained in persistent storage and can be
+ * recovered on CBlock server restart.
+ */
+public class TestCBlockServerPersistence {
+
+  /**
+   * Test when cblock server fails with volume meta data, the meta data can be
+   * restored correctly.
+   * @throws Exception
+   */
+  @Test
+  public void testWriteToPersistentStore() throws Exception {
+    String userName = "testWriteToPersistentStore";
+    String volumeName1 = "testVolume1";
+    String volumeName2 = "testVolume2";
+    long volumeSize1 = 30L*1024*1024*1024;
+    long volumeSize2 = 15L*1024*1024*1024;
+    int blockSize = 4096;
+    CBlockManager cBlockManager = null;
+    CBlockManager cBlockManager1 = null;
+    String dbPath = "/tmp/testCblockPersistence.dat";
+    try {
+      IStorageClient storageClient = new MockStorageClient();
+      CBlockConfiguration conf = new CBlockConfiguration();
+      conf.set(DFS_CBLOCK_SERVICE_LEVELDB_PATH_KEY, dbPath);
+      cBlockManager = new CBlockManager(conf, storageClient);
+      cBlockManager.createVolume(userName, volumeName1, volumeSize1, blockSize);
+      cBlockManager.createVolume(userName, volumeName2, volumeSize2, blockSize);
+      List<VolumeDescriptor> allVolumes = cBlockManager.getAllVolumes();
+      // close the cblock server. Since meta data is written to disk on volume
+      // creation, closing server here is the same as a cblock server crash.
+      cBlockManager.close();
+      cBlockManager.stop();
+      cBlockManager.join();
+      cBlockManager = null;
+      assertEquals(2, allVolumes.size());
+      VolumeDescriptor volumeDescriptor1 = allVolumes.get(0);
+      VolumeDescriptor volumeDescriptor2 = allVolumes.get(1);
+
+      // create a new cblock server instance. This is just the
+      // same as restarting cblock server.
+      IStorageClient storageClient1 = new MockStorageClient();
+      CBlockConfiguration conf1 = new CBlockConfiguration();
+      conf1.set(DFS_CBLOCK_SERVICE_LEVELDB_PATH_KEY, dbPath);
+      cBlockManager1 = new CBlockManager(conf1, storageClient1);
+      List<VolumeDescriptor> allVolumes1 = cBlockManager1.getAllVolumes();
+      assertEquals(2, allVolumes1.size());
+      VolumeDescriptor newvolumeDescriptor1 = allVolumes1.get(0);
+      VolumeDescriptor newvolumeDescriptor2 = allVolumes1.get(1);
+
+      // It seems levelDB iterator gets keys in the same order as keys
+      // are inserted, in which case the else clause should never happen.
+      // But still kept the second clause if it is possible to get different
+      // key ordering from leveldb. And we do not rely on the ordering of keys
+      // here.
+      if (volumeDescriptor1.getVolumeName().equals(
+          newvolumeDescriptor1.getVolumeName())) {
+        assertEquals(volumeDescriptor1, newvolumeDescriptor1);
+        assertEquals(volumeDescriptor2, newvolumeDescriptor2);
+      } else {
+        assertEquals(volumeDescriptor1, newvolumeDescriptor2);
+        assertEquals(volumeDescriptor2, newvolumeDescriptor1);
+      }
+    } finally {
+      if (cBlockManager != null) {
+        cBlockManager.clean();
+      }
+      if (cBlockManager1 != null) {
+        cBlockManager1.clean();
+      }
+    }
+  }
+}

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

@@ -29,7 +29,7 @@ import org.apache.hadoop.ozone.container.common.helpers.ChunkInfo;
 import org.apache.hadoop.ozone.container.common.helpers.ContainerData;
 import org.apache.hadoop.ozone.container.common.helpers.ContainerUtils;
 import org.apache.hadoop.ozone.container.common.helpers.KeyData;
-import org.apache.hadoop.ozone.container.common.utils.LevelDBStore;
+import org.apache.hadoop.utils.LevelDBStore;
 import org.apache.hadoop.ozone.web.utils.OzoneUtils;
 import org.apache.hadoop.scm.container.common.helpers.Pipeline;
 import org.junit.After;