Add TestRollingUpgradeDowngrade.java for HDFS-6024

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-5535@1572434 13f79535-47bb-0310-9956-ffa450edef68

Author: Jing9

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRollingUpgradeDowngrade.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.hdfs;
+
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.spy;
+
+import java.io.IOException;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
+import org.apache.hadoop.hdfs.qjournal.MiniQJMHACluster;
+import org.apache.hadoop.hdfs.server.common.IncorrectVersionException;
+import org.apache.hadoop.hdfs.server.namenode.NNStorage;
+import org.apache.hadoop.hdfs.server.namenode.NameNodeLayoutVersion;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestRollingUpgradeDowngrade {
+
+  @Test(timeout = 300000)
+  public void testDowngrade() throws IOException {
+    final Configuration conf = new HdfsConfiguration();
+    MiniQJMHACluster cluster = null;
+    final Path foo = new Path("/foo");
+    final Path bar = new Path("/bar");
+
+    try {
+      cluster = new MiniQJMHACluster.Builder(conf).build();
+      MiniDFSCluster dfsCluster = cluster.getDfsCluster();
+      dfsCluster.waitActive();
+
+      dfsCluster.transitionToActive(0);
+      DistributedFileSystem dfs = dfsCluster.getFileSystem(0);
+      dfs.mkdirs(foo);
+
+      // start rolling upgrade
+      RollingUpgradeInfo info = dfs
+          .rollingUpgrade(RollingUpgradeAction.PREPARE);
+      Assert.assertTrue(info.isStarted());
+      dfs.mkdirs(bar);
+      dfs.close();
+
+      dfsCluster.restartNameNode(0, true, "-rollingUpgrade", "downgrade");
+      // shutdown NN1
+      dfsCluster.shutdownNameNode(1);
+      dfsCluster.transitionToActive(0);
+
+      dfs = dfsCluster.getFileSystem(0);
+      Assert.assertTrue(dfs.exists(foo));
+      Assert.assertTrue(dfs.exists(bar));
+    } finally {
+      if (cluster != null) {
+        cluster.shutdown();
+      }
+    }
+  }
+
+  /**
+   * Ensure that during downgrade the NN fails to load a fsimage with newer
+   * format.
+   */
+  @Test(expected = IncorrectVersionException.class)
+  public void testRejectNewFsImage() throws IOException {
+    final Configuration conf = new Configuration();
+    MiniDFSCluster cluster = null;
+    try {
+      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0).build();
+      cluster.waitActive();
+      DistributedFileSystem fs = cluster.getFileSystem();
+      fs.setSafeMode(SafeModeAction.SAFEMODE_ENTER);
+      fs.saveNamespace();
+      fs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE);
+      NNStorage storage = spy(cluster.getNameNode().getFSImage().getStorage());
+      int futureVersion = NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION - 1;
+      doReturn(futureVersion).when(storage).getServiceLayoutVersion();
+      storage.writeAll();
+      cluster.restartNameNode(0, true, "-rollingUpgrade", "downgrade");
+    } finally {
+      if (cluster != null) {
+        cluster.shutdown();
+      }
+    }
+  }
+}