HDFS-11714. Newly added NN storage directory won't get initialized and cause space exhaustion. Contributed by Kihwal Lee.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImage.java

@@ -97,6 +97,16 @@ public class FSImage implements Closeable {
 
   protected NNStorageRetentionManager archivalManager;
 
+  /**
+   * The collection of newly added storage directories. These are partially
+   * formatted then later fully populated along with a VERSION file.
+   * For HA, the second part is done when the next checkpoint is saved.
+   * This set will be cleared once a VERSION file is created.
+   * For non-HA, a new fsimage will be locally generated along with a new
+   * VERSION file. This set is not used for non-HA mode.
+   */
+  private Set<StorageDirectory> newDirs = null;
+
   /* Used to make sure there are no concurrent checkpoints for a given txid
    * The checkpoint here could be one of the following operations.
    * a. checkpoint when NN is in standby.
@@ -260,9 +270,26 @@ public class FSImage implements Closeable {
         throw new IOException(StorageState.NON_EXISTENT + 
                               " state cannot be here");
       case NOT_FORMATTED:
+        // Create a dir structure, but not the VERSION file. The presence of
+        // VERSION is checked in the inspector's needToSave() method and
+        // saveNamespace is triggered if it is absent. This will bring
+        // the storage state uptodate along with a new VERSION file.
+        // If HA is enabled, NNs start up as standby so saveNamespace is not
+        // triggered.
         LOG.info("Storage directory " + sd.getRoot() + " is not formatted.");
         LOG.info("Formatting ...");
         sd.clearDirectory(); // create empty currrent dir
+        // For non-HA, no further action is needed here, as saveNamespace will
+        // take care of the rest.
+        if (!target.isHaEnabled()) {
+          continue;
+        }
+        // If HA is enabled, save the dirs to create a version file later when
+        // a checkpoint image is saved.
+        if (newDirs == null) {
+          newDirs = new HashSet<StorageDirectory>();
+        }
+        newDirs.add(sd);
         break;
       default:
         break;
@@ -288,7 +315,27 @@ public class FSImage implements Closeable {
     
     return loadFSImage(target, startOpt, recovery);
   }
-  
+
+  /**
+   * Create a VERSION file in the newly added storage directories.
+   */
+  private void initNewDirs() {
+    if (newDirs == null) {
+      return;
+    }
+    for (StorageDirectory sd : newDirs) {
+      try {
+        storage.writeProperties(sd);
+        LOG.info("Wrote VERSION in the new storage, " + sd.getCurrentDir());
+      } catch (IOException e) {
+        // Failed to create a VERSION file. Report the error.
+        storage.reportErrorOnFile(sd.getVersionFile());
+      }
+    }
+    newDirs.clear();
+    newDirs = null;
+  }
+
   /**
    * For each storage directory, performs recovery of incomplete transitions
    * (eg. upgrade, rollback, checkpoint) and inserts the directory's storage
@@ -1329,6 +1376,9 @@ public class FSImage implements Closeable {
     if (txid > storage.getMostRecentCheckpointTxId()) {
       storage.setMostRecentCheckpointInfo(txid, Time.now());
     }
+
+    // Create a version file in any new storage directory.
+    initNewDirs();
   }
 
   @Override

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestStandbyCheckpoints.java

@@ -32,6 +32,7 @@ import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.MiniDFSNNTopology;
+import org.apache.hadoop.hdfs.server.common.Util;
 import org.apache.hadoop.hdfs.server.namenode.*;
 import org.apache.hadoop.hdfs.server.namenode.NNStorage.NameNodeFile;
 import org.apache.hadoop.hdfs.util.Canceler;
@@ -41,6 +42,7 @@ import org.apache.hadoop.io.compress.GzipCodec;
 import org.apache.hadoop.ipc.StandbyException;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.test.GenericTestUtils.DelayAnswer;
+import org.apache.hadoop.test.PathUtils;
 import org.apache.hadoop.util.ThreadUtil;
 import org.junit.After;
 import org.junit.Before;
@@ -168,6 +170,44 @@ public class TestStandbyCheckpoints {
       purgeLogsOlderThan(Mockito.anyLong());
   }
 
+  @Test
+  public void testNewDirInitAfterCheckpointing() throws Exception {
+    File hdfsDir = new File(PathUtils.getTestDir(TestStandbyCheckpoints.class),
+        "testNewDirInitAfterCheckpointing");
+    File nameDir = new File(hdfsDir, "name1");
+    assert nameDir.mkdirs();
+
+    // Restart nn0 with an additional name dir.
+    String existingDir = cluster.getConfiguration(0).
+        get(DFSConfigKeys.DFS_NAMENODE_NAME_DIR_KEY);
+    cluster.getConfiguration(0).set(DFSConfigKeys.DFS_NAMENODE_NAME_DIR_KEY,
+        existingDir + "," + Util.fileAsURI(nameDir).toString());
+    cluster.restartNameNode(0);
+    nn0 = cluster.getNameNode(0);
+    cluster.transitionToActive(0);
+
+    // "current" is created, but current/VERSION isn't.
+    File currDir = new File(nameDir, "current");
+    File versionFile = new File(currDir, "VERSION");
+    assert currDir.exists();
+    assert !versionFile.exists();
+
+    // Trigger a checkpointing and upload.
+    doEdits(0, 10);
+    HATestUtil.waitForStandbyToCatchUp(nn0, nn1);
+
+    // The version file will be created if a checkpoint is uploaded.
+    // Wait for it to happen up to 10 seconds.
+    for (int i = 0; i < 20; i++) {
+      if (versionFile.exists()) {
+        break;
+      }
+      Thread.sleep(500);
+    }
+    // VERSION must have been created.
+    assert versionFile.exists();
+  }
+
   /**
    * Test for the case when both of the NNs in the cluster are
    * in the standby state, and thus are both creating checkpoints