HDFS-13008. Ozone: Add DN container open/close state to container report. Contributed by Xiaoyu Yao.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/proto/DatanodeContainerProtocol.proto

@@ -201,10 +201,13 @@ message ContainerData {
   repeated KeyValue metadata = 2;
   optional string dbPath = 3;
   optional string containerPath = 4;
-  optional bool open = 5 [default = true];
   optional string hash = 6;
   optional int64 bytesUsed = 7;
   optional int64 size = 8;
+  optional int64 keyCount = 9;
+  //TODO: change required after we switch container ID from string to long
+  optional int64 containerID = 10;
+  optional LifeCycleState state = 11 [default = OPEN];
 }
 
 message ContainerMeta {

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

@@ -45,24 +45,26 @@ public class ContainerData {
   private String dbPath;  // Path to Level DB Store.
   // Path to Physical file system where container and checksum are stored.
   private String containerFilePath;
-  private boolean open;
   private String hash;
   private AtomicLong bytesUsed;
   private long maxSize;
+  private Long containerID;
+  private OzoneProtos.LifeCycleState state;
 
   /**
    * Constructs a  ContainerData Object.
    *
    * @param containerName - Name
    */
-  public ContainerData(String containerName, Configuration conf) {
+  public ContainerData(String containerName, Long containerID,
+      Configuration conf) {
     this.metadata = new TreeMap<>();
     this.containerName = containerName;
-    this.open = true;
     this.maxSize = conf.getLong(ScmConfigKeys.SCM_CONTAINER_CLIENT_MAX_SIZE_KEY,
         ScmConfigKeys.SCM_CONTAINER_CLIENT_MAX_SIZE_DEFAULT) * OzoneConsts.GB;
     this.bytesUsed =  new AtomicLong(0L);
-
+    this.containerID = containerID;
+    this.state = OzoneProtos.LifeCycleState.OPEN;
   }
 
   /**
@@ -74,7 +76,8 @@ public ContainerData(String containerName, Configuration conf) {
   public static ContainerData getFromProtBuf(
       ContainerProtos.ContainerData protoData, Configuration conf)
       throws IOException {
-    ContainerData data = new ContainerData(protoData.getName(), conf);
+    ContainerData data = new ContainerData(protoData.getName(),
+        protoData.getContainerID(), conf);
     for (int x = 0; x < protoData.getMetadataCount(); x++) {
       data.addMetadata(protoData.getMetadata(x).getKey(),
           protoData.getMetadata(x).getValue());
@@ -88,10 +91,8 @@ public static ContainerData getFromProtBuf(
       data.setDBPath(protoData.getDbPath());
     }
 
-    if (protoData.hasOpen()) {
+    if (protoData.hasState()) {
-      data.setOpen(protoData.getOpen());
+      data.setState(protoData.getState());
-    } else {
-      data.setOpen(true);
     }
 
     if(protoData.hasHash()) {
@@ -117,6 +118,7 @@ public ContainerProtos.ContainerData getProtoBufMessage() {
     ContainerProtos.ContainerData.Builder builder = ContainerProtos
         .ContainerData.newBuilder();
     builder.setName(this.getContainerName());
+    builder.setContainerID(this.getContainerID());
 
     if (this.getDBPath() != null) {
       builder.setDbPath(this.getDBPath());
@@ -130,7 +132,7 @@ public ContainerProtos.ContainerData getProtoBufMessage() {
       builder.setContainerPath(this.getContainerPath());
     }
 
-    builder.setOpen(this.isOpen());
+    builder.setState(this.getState());
 
     for (Map.Entry<String, String> entry : metadata.entrySet()) {
       OzoneProtos.KeyValue.Builder keyValBuilder =
@@ -143,6 +145,10 @@ public ContainerProtos.ContainerData getProtoBufMessage() {
       builder.setBytesUsed(this.getBytesUsed());
     }
 
+    if (this.getKeyCount() >= 0) {
+      builder.setKeyCount(this.getKeyCount());
+    }
+
     if (this.getMaxSize() >= 0) {
       builder.setSize(this.getMaxSize());
     }
@@ -245,19 +251,36 @@ public void setContainerPath(String containerPath) {
     this.containerFilePath = containerPath;
   }
 
+  /**
+   * Get container ID.
+   * @return - container ID.
+   */
+  public synchronized Long getContainerID() {
+    return containerID;
+  }
+
+  public synchronized  void setState(OzoneProtos.LifeCycleState state) {
+    this.state = state;
+  }
+
+  public synchronized OzoneProtos.LifeCycleState getState() {
+    return this.state;
+  }
+
   /**
    * checks if the container is open.
    * @return - boolean
    */
   public synchronized  boolean isOpen() {
-    return open;
+    return OzoneProtos.LifeCycleState.OPEN == state;
   }
 
   /**
    * Marks this container as closed.
    */
   public synchronized void closeContainer() {
-    setOpen(false);
+    // TODO: closed or closing here
+    setState(OzoneProtos.LifeCycleState.CLOSED);
 
     // Some thing brain dead for now. name + Time stamp of when we get the close
     // container message.
@@ -277,14 +300,6 @@ public void setHash(String hash) {
     this.hash = hash;
   }
 
-  /**
-   * Sets the open or closed values.
-   * @param open
-   */
-  public synchronized void setOpen(boolean open) {
-    this.open = open;
-  }
-
   public void setMaxSize(long maxSize) {
     this.maxSize = maxSize;
   }

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

@@ -618,7 +618,8 @@ public Pipeline getContainer(String containerName) throws IOException {
   }
 
   @VisibleForTesting
-  ContainerInfo getContainerInfo(String containerName) throws IOException {
+  public ContainerInfo getContainerInfo(String containerName)
+      throws IOException {
     return scmContainerManager.getContainer(containerName);
   }
 

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

@@ -25,6 +25,7 @@
 
 import org.apache.hadoop.hdfs.ozone.protocol.proto.ContainerProtos.ContainerData;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
+import org.apache.hadoop.ozone.protocol.proto.OzoneProtos;
 import org.apache.hadoop.ozone.scm.cli.OzoneCommandHandler;
 import org.apache.hadoop.scm.client.ScmClient;
 import org.apache.hadoop.scm.container.common.helpers.Pipeline;
@@ -75,7 +76,9 @@ public void execute(CommandLine cmd) throws IOException {
     // Print container report info.
     logOut("Container Name: %s",
         containerData.getName());
-    String openStatus = containerData.getOpen() ? "OPEN" : "CLOSED";
+    String openStatus =
+        containerData.getState() == OzoneProtos.LifeCycleState.OPEN ? "OPEN" :
+            "CLOSED";
     logOut("Container State: %s", openStatus);
     if (!containerData.getHash().isEmpty()) {
       logOut("Container Hash: %s", containerData.getHash());

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/StorageContainerDatanodeProtocol.proto

@@ -104,6 +104,7 @@ message ContainerInfo {
   optional int64 readBytes = 8;
   optional int64 writeBytes = 9;
   required int64 containerID = 10;
+  optional hadoop.hdfs.ozone.LifeCycleState state = 11;
 }
 
 // The deleted blocks which are stored in deletedBlock.db of scm.

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

@@ -128,7 +128,7 @@ private void createToDeleteBlocks(ContainerManager mgr,
       int numOfChunksPerBlock, File chunkDir) throws IOException {
     for (int x = 0; x < numOfContainers; x++) {
       String containerName = OzoneUtils.getRequestID();
-      ContainerData data = new ContainerData(containerName, conf);
+      ContainerData data = new ContainerData(containerName, new Long(x), conf);
       mgr.createContainer(createSingleNodePipeline(containerName), data);
       data = mgr.readContainer(containerName);
       MetadataStore metadata = KeyUtils.getDB(data, conf);
@@ -216,6 +216,7 @@ public void testBlockDeletion() throws Exception {
     Assert.assertEquals(0, getUnderDeletionBlocksCount(meta));
 
     svc.shutdown();
+    shutdownContainerMangaer(containerManager);
   }
 
   @Test
@@ -244,6 +245,7 @@ public void testShutdownService() throws Exception {
     // Shutdown service and verify all threads are stopped
     service.shutdown();
     GenericTestUtils.waitFor(() -> service.getThreadCount() == 0, 100, 1000);
+    shutdownContainerMangaer(containerManager);
   }
 
   @Test
@@ -302,6 +304,7 @@ public void testBlockDeletionTimeout() throws Exception {
     Assert.assertTrue(!newLog.getOutput().contains(
         "Background task executes timed out, retrying in next interval"));
     svc.shutdown();
+    shutdownContainerMangaer(containerManager);
   }
 
   @Test(timeout = 30000)
@@ -333,6 +336,7 @@ public void testContainerThrottle() throws Exception {
       Assert.assertEquals(10, chunksDir.listFiles().length);
     } finally {
       service.shutdown();
+      shutdownContainerMangaer(containerManager);
     }
   }
 
@@ -376,6 +380,17 @@ public void testBlockThrottle() throws Exception {
       Assert.assertEquals(0, chunksDir.listFiles().length);
     } finally {
       service.shutdown();
+      shutdownContainerMangaer(containerManager);
+    }
+  }
+
+  private void shutdownContainerMangaer(ContainerManager mgr)
+      throws IOException {
+    mgr.writeLock();
+    try {
+      mgr.shutdown();
+    } finally {
+      mgr.writeUnlock();
     }
   }
 }

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

@@ -94,7 +94,7 @@ public void testRandomChoosingPolicy() throws IOException {
     int numContainers = 10;
     for (int i = 0; i < numContainers; i++) {
       String containerName = OzoneUtils.getRequestID();
-      ContainerData data = new ContainerData(containerName, conf);
+      ContainerData data = new ContainerData(containerName, new Long(i), conf);
       containerManager.createContainer(createSingleNodePipeline(containerName),
           data);
       Assert.assertTrue(
@@ -144,7 +144,7 @@ public void testTopNOrderedChoosingPolicy() throws IOException {
     // create [numContainers + 1] containers
     for (int i = 0; i <= numContainers; i++) {
       String containerName = OzoneUtils.getRequestID();
-      ContainerData data = new ContainerData(containerName, conf);
+      ContainerData data = new ContainerData(containerName, new Long(i), conf);
       containerManager.createContainer(createSingleNodePipeline(containerName),
           data);
       Assert.assertTrue(

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

@@ -101,6 +101,7 @@ public class TestContainerPersistence {
   private static KeyManagerImpl keyManager;
   private static OzoneConfiguration conf;
   private static List<StorageLocation> pathLists = new LinkedList<>();
+  private Long  containerID = 8888L;;
 
   @BeforeClass
   public static void init() throws Throwable {
@@ -180,7 +181,7 @@ public void cleanupDir() throws IOException {
   public void testCreateContainer() throws Exception {
 
     String containerName = OzoneUtils.getRequestID();
-    ContainerData data = new ContainerData(containerName, conf);
+    ContainerData data = new ContainerData(containerName, containerID++, conf);
     data.addMetadata("VOLUME", "shire");
     data.addMetadata("owner)", "bilbo");
     containerManager.createContainer(createSingleNodePipeline(containerName),
@@ -216,7 +217,7 @@ public void testCreateContainer() throws Exception {
   public void testCreateDuplicateContainer() throws Exception {
     String containerName = OzoneUtils.getRequestID();
 
-    ContainerData data = new ContainerData(containerName, conf);
+    ContainerData data = new ContainerData(containerName, containerID++, conf);
     data.addMetadata("VOLUME", "shire");
     data.addMetadata("owner)", "bilbo");
     containerManager.createContainer(createSingleNodePipeline(containerName),
@@ -236,14 +237,14 @@ public void testDeleteContainer() throws Exception {
     String containerName2 = OzoneUtils.getRequestID();
 
 
-    ContainerData data = new ContainerData(containerName1, conf);
+    ContainerData data = new ContainerData(containerName1, containerID++, conf);
     data.addMetadata("VOLUME", "shire");
     data.addMetadata("owner)", "bilbo");
     containerManager.createContainer(createSingleNodePipeline(containerName1),
         data);
     containerManager.closeContainer(containerName1);
 
-    data = new ContainerData(containerName2, conf);
+    data = new ContainerData(containerName2, containerID++, conf);
     data.addMetadata("VOLUME", "shire");
     data.addMetadata("owner)", "bilbo");
     containerManager.createContainer(createSingleNodePipeline(containerName2),
@@ -263,7 +264,7 @@ public void testDeleteContainer() throws Exception {
     // Let us make sure that we are able to re-use a container name after
     // delete.
 
-    data = new ContainerData(containerName1, conf);
+    data = new ContainerData(containerName1, containerID++, conf);
     data.addMetadata("VOLUME", "shire");
     data.addMetadata("owner)", "bilbo");
     containerManager.createContainer(createSingleNodePipeline(containerName1),
@@ -301,7 +302,8 @@ public void testGetContainerReports() throws Exception{
 
     for (int i = 0; i < count; i++) {
       String containerName = OzoneUtils.getRequestID();
-      ContainerData data = new ContainerData(containerName, conf);
+      ContainerData data = new ContainerData(containerName, containerID++,
+          conf);
       containerManager.createContainer(createSingleNodePipeline(containerName),
           data);
 
@@ -337,8 +339,8 @@ public void testListContainer() throws IOException {
     Map<String, ContainerData> testMap = new HashMap<>();
     for (int x = 0; x < count; x++) {
       String containerName = OzoneUtils.getRequestID();
-
+      ContainerData data = new ContainerData(containerName, containerID++,
-      ContainerData data = new ContainerData(containerName, conf);
+          conf);
       data.addMetadata("VOLUME", "shire");
       data.addMetadata("owner)", "bilbo");
       containerManager.createContainer(createSingleNodePipeline(containerName),
@@ -373,7 +375,7 @@ private ChunkInfo writeChunkHelper(String containerName, String keyName,
     final int datalen = 1024;
     Pipeline newPipeline =
         new Pipeline(containerName, pipeline.getPipelineChannel());
-    ContainerData cData = new ContainerData(containerName, conf);
+    ContainerData cData = new ContainerData(containerName, containerID++, conf);
     cData.addMetadata("VOLUME", "shire");
     cData.addMetadata("owner", "bilbo");
     if(!containerManager.getContainerMap()
@@ -421,7 +423,7 @@ public void testWritReadManyChunks() throws IOException,
     Pipeline pipeline = createSingleNodePipeline(containerName);
     Map<String, ChunkInfo> fileHashMap = new HashMap<>();
 
-    ContainerData cData = new ContainerData(containerName, conf);
+    ContainerData cData = new ContainerData(containerName, containerID++, conf);
     cData.addMetadata("VOLUME", "shire");
     cData.addMetadata("owner)", "bilbo");
     containerManager.createContainer(pipeline, cData);
@@ -484,7 +486,7 @@ public void testPartialRead() throws Exception {
     String keyName = OzoneUtils.getRequestID();
     Pipeline pipeline = createSingleNodePipeline(containerName);
 
-    ContainerData cData = new ContainerData(containerName, conf);
+    ContainerData cData = new ContainerData(containerName, containerID++, conf);
     cData.addMetadata("VOLUME", "shire");
     cData.addMetadata("owner)", "bilbo");
     containerManager.createContainer(pipeline, cData);
@@ -518,7 +520,7 @@ public void testOverWrite() throws IOException,
     String keyName = OzoneUtils.getRequestID();
     Pipeline pipeline = createSingleNodePipeline(containerName);
 
-    ContainerData cData = new ContainerData(containerName, conf);
+    ContainerData cData = new ContainerData(containerName, containerID++, conf);
     cData.addMetadata("VOLUME", "shire");
     cData.addMetadata("owner)", "bilbo");
     containerManager.createContainer(pipeline, cData);
@@ -560,7 +562,7 @@ public void testMultipleWriteSingleRead() throws IOException,
     String keyName = OzoneUtils.getRequestID();
     Pipeline pipeline = createSingleNodePipeline(containerName);
 
-    ContainerData cData = new ContainerData(containerName, conf);
+    ContainerData cData = new ContainerData(containerName, containerID++, conf);
     cData.addMetadata("VOLUME", "shire");
     cData.addMetadata("owner)", "bilbo");
     containerManager.createContainer(pipeline, cData);
@@ -598,7 +600,7 @@ public void testDeleteChunk() throws IOException,
     String keyName = OzoneUtils.getRequestID();
     Pipeline pipeline = createSingleNodePipeline(containerName);
 
-    ContainerData cData = new ContainerData(containerName, conf);
+    ContainerData cData = new ContainerData(containerName, containerID++, conf);
     cData.addMetadata("VOLUME", "shire");
     cData.addMetadata("owner)", "bilbo");
     containerManager.createContainer(pipeline, cData);
@@ -744,7 +746,7 @@ public void testDeleteKeyTwice() throws IOException,
   @Test
   public void testUpdateContainer() throws IOException {
     String containerName = OzoneUtils.getRequestID();
-    ContainerData data = new ContainerData(containerName, conf);
+    ContainerData data = new ContainerData(containerName, containerID++, conf);
     data.addMetadata("VOLUME", "shire");
     data.addMetadata("owner", "bilbo");
 
@@ -755,7 +757,8 @@ public void testUpdateContainer() throws IOException {
     File orgContainerFile = containerManager.getContainerFile(data);
     Assert.assertTrue(orgContainerFile.exists());
 
-    ContainerData newData = new ContainerData(containerName, conf);
+    ContainerData newData = new ContainerData(containerName, containerID++,
+        conf);
     newData.addMetadata("VOLUME", "shire_new");
     newData.addMetadata("owner", "bilbo_new");
 
@@ -807,7 +810,7 @@ public void testUpdateContainer() throws IOException {
     }
 
     // Update with force flag, it should be success.
-    newData = new ContainerData(containerName, conf);
+    newData = new ContainerData(containerName, containerID++, conf);
     newData.addMetadata("VOLUME", "shire_new_1");
     newData.addMetadata("owner", "bilbo_new_1");
     containerManager.updateContainer(createSingleNodePipeline(containerName),

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/ozone/ksm/TestContainerReportWithKeys.java

@@ -0,0 +1,138 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.ksm;
+
+import org.apache.commons.lang.RandomStringUtils;
+import org.apache.hadoop.conf.OzoneConfiguration;
+import org.apache.hadoop.ozone.MiniOzoneClassicCluster;
+import org.apache.hadoop.ozone.OzoneConfigKeys;
+import org.apache.hadoop.ozone.OzoneConsts;
+import org.apache.hadoop.ozone.client.*;
+import org.apache.hadoop.ozone.client.io.OzoneOutputStream;
+import org.apache.hadoop.ozone.container.common.helpers.ContainerData;
+import org.apache.hadoop.ozone.ksm.helpers.KsmKeyArgs;
+import org.apache.hadoop.ozone.ksm.helpers.KsmKeyLocationInfo;
+import org.apache.hadoop.ozone.protocol.proto.OzoneProtos;
+import org.apache.hadoop.ozone.scm.StorageContainerManager;
+import org.apache.hadoop.scm.container.common.helpers.ContainerInfo;
+import org.apache.hadoop.scm.container.common.helpers.StorageContainerException;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+/**
+ * This class tests container report with DN container state info.
+ */
+public class TestContainerReportWithKeys {
+  private static final Logger LOG = LoggerFactory.getLogger(
+      TestContainerReportWithKeys.class);
+  private static MiniOzoneClassicCluster cluster = null;
+  private static OzoneConfiguration conf;
+  private static StorageContainerManager scm;
+
+  @Rule
+  public ExpectedException exception = ExpectedException.none();
+
+  /**
+   * Create a MiniDFSCluster for testing.
+   * <p>
+   * Ozone is made active by setting OZONE_ENABLED = true and
+   * OZONE_HANDLER_TYPE_KEY = "distributed"
+   *
+   * @throws IOException
+   */
+  @BeforeClass
+  public static void init() throws Exception {
+    conf = new OzoneConfiguration();
+    conf.set(OzoneConfigKeys.OZONE_HANDLER_TYPE_KEY,
+        OzoneConsts.OZONE_HANDLER_DISTRIBUTED);
+    cluster = new MiniOzoneClassicCluster.Builder(conf)
+        .setHandlerType(OzoneConsts.OZONE_HANDLER_DISTRIBUTED).build();
+    scm = cluster.getStorageContainerManager();
+  }
+
+  /**
+   * Shutdown MiniDFSCluster.
+   */
+  @AfterClass
+  public static void shutdown() {
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  @Test
+  public void testContainerReportKeyWrite() throws Exception {
+    final String volumeName = "volume" + RandomStringUtils.randomNumeric(5);
+    final String bucketName = "bucket" + RandomStringUtils.randomNumeric(5);
+    final String keyName = "key" + RandomStringUtils.randomNumeric(5);
+    final int keySize = 100;
+
+    OzoneClient client = OzoneClientFactory.getClient(conf);
+    ObjectStore objectStore = client.getObjectStore();
+    objectStore.createVolume(volumeName);
+    objectStore.getVolume(volumeName).createBucket(bucketName);
+    OzoneOutputStream key = objectStore.getVolume(volumeName).getBucket(bucketName)
+        .createKey(keyName, keySize, ReplicationType.STAND_ALONE,
+            ReplicationFactor.ONE);
+    String dataString = RandomStringUtils.randomAlphabetic(keySize);
+    key.write(dataString.getBytes());
+    key.close();
+
+    KsmKeyArgs keyArgs = new KsmKeyArgs.Builder()
+        .setVolumeName(volumeName)
+        .setBucketName(bucketName)
+        .setKeyName(keyName)
+        .setType(OzoneProtos.ReplicationType.STAND_ALONE)
+        .setFactor(OzoneProtos.ReplicationFactor.ONE).setDataSize(keySize)
+        .build();
+
+
+    KsmKeyLocationInfo keyInfo =
+        cluster.getKeySpaceManager().lookupKey(keyArgs).getKeyLocationVersions()
+            .get(0).getBlocksLatestVersionOnly().get(0);
+
+    ContainerData cd = getContainerData(cluster, keyInfo.getContainerName());
+
+    LOG.info("DN Container Data:  keyCount: {} used: {} ",
+        cd.getKeyCount(), cd.getBytesUsed());
+
+    ContainerInfo cinfo = scm.getContainerInfo(keyInfo.getContainerName());
+
+    LOG.info("SCM Container Info keyCount: {} usedBytes: {}",
+        cinfo.getNumberOfKeys(), cinfo.getUsedBytes());
+  }
+
+
+  private static ContainerData getContainerData(MiniOzoneClassicCluster clus,
+      String containerName) {
+    ContainerData containerData = null;
+    try {
+      containerData = clus.getDataNodes().get(0).getOzoneContainerManager()
+          .getContainerManager().readContainer(containerName);
+    } catch (StorageContainerException e) {
+      throw new AssertionError(e);
+    }
+    return containerData;
+  }
+}