HDFS-12875. RBF: Complete logic for -readonly option of dfsrouteradmin add command. Contributed by Inigo Goiri.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcServer.java

@@ -103,8 +103,10 @@ import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifie
 import org.apache.hadoop.hdfs.server.federation.resolver.ActiveNamenodeResolver;
 import org.apache.hadoop.hdfs.server.federation.resolver.FederationNamespaceInfo;
 import org.apache.hadoop.hdfs.server.federation.resolver.FileSubclusterResolver;
+import org.apache.hadoop.hdfs.server.federation.resolver.MountTableResolver;
 import org.apache.hadoop.hdfs.server.federation.resolver.PathLocation;
 import org.apache.hadoop.hdfs.server.federation.resolver.RemoteLocation;
+import org.apache.hadoop.hdfs.server.federation.store.records.MountTable;
 import org.apache.hadoop.hdfs.server.namenode.LeaseExpiredException;
 import org.apache.hadoop.hdfs.server.namenode.NameNode.OperationCategory;
 import org.apache.hadoop.hdfs.server.namenode.NotReplicatedYetException;
@@ -1982,6 +1984,17 @@ public class RouterRpcServer extends AbstractService implements ClientProtocol {
             this.subclusterResolver);
       }
 
+      // We may block some write operations
+      if (opCategory.get() == OperationCategory.WRITE) {
+        // Check if the path is in a read only mount point
+        if (isPathReadOnly(path)) {
+          if (this.rpcMonitor != null) {
+            this.rpcMonitor.routerFailureReadOnly();
+          }
+          throw new IOException(path + " is in a read only mount point");
+        }
+      }
+
       return location.getDestinations();
     } catch (IOException ioe) {
       if (this.rpcMonitor != null) {
@@ -1991,6 +2004,27 @@ public class RouterRpcServer extends AbstractService implements ClientProtocol {
     }
   }
 
+  /**
+   * Check if a path is in a read only mount point.
+   *
+   * @param path Path to check.
+   * @return If the path is in a read only mount point.
+   */
+  private boolean isPathReadOnly(final String path) {
+    if (subclusterResolver instanceof MountTableResolver) {
+      try {
+        MountTableResolver mountTable = (MountTableResolver)subclusterResolver;
+        MountTable entry = mountTable.getMountPoint(path);
+        if (entry != null && entry.isReadOnly()) {
+          return true;
+        }
+      } catch (IOException e) {
+        LOG.error("Cannot get mount point: {}", e.getMessage());
+      }
+    }
+    return false;
+  }
+
   /**
    * Get the modification dates for mount points.
    *

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/federation/RouterAdmin.java

@@ -77,7 +77,7 @@ public class RouterAdmin extends Configured implements Tool {
   public void printUsage() {
     String usage = "Federation Admin Tools:\n"
         + "\t[-add <source> <nameservice> <destination> "
-        + "[-readonly] [-order HASH|LOCAL|RANDOM|HASH_ALL]]\n"
+        + "[-readonly]\n"
         + "\t[-rm <source>]\n"
         + "\t[-ls <path>]\n";
     System.out.println(usage);

hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSCommands.md

@@ -425,7 +425,7 @@ Runs the DFS router. See [Router](./HDFSRouterFederation.html#Router) for more i
 Usage:
 
       hdfs dfsrouteradmin
-          [-add <source> <nameservice> <destination>]
+          [-add <source> <nameservice> <destination> [-readonly]]
           [-rm <source>]
           [-ls <path>]
 

hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSRouterFederation.md

@@ -184,6 +184,10 @@ For example, to create three mount points and list them:
     [hdfs]$ $HADOOP_HOME/bin/hdfs dfsrouteradmin -add /data/app2 ns3 /data/app2
     [hdfs]$ $HADOOP_HOME/bin/hdfs dfsrouteradmin -ls
 
+It also supports mount points that disallow writes:
+
+    [hdfs]$ $HADOOP_HOME/bin/hdfs dfsrouteradmin -add /readonly ns1 / -readonly
+
 If a mount point is not set, the Router will map it to the default namespace `dfs.federation.router.default.nameserviceId`.
 
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/federation/FederationTestUtils.java

@@ -20,7 +20,6 @@ package org.apache.hadoop.hdfs.server.federation;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
-import static org.junit.Assert.fail;
 
 import java.io.BufferedReader;
 import java.io.FileNotFoundException;
@@ -52,6 +51,9 @@ import org.apache.hadoop.hdfs.server.federation.resolver.FederationNamenodeServi
 import org.apache.hadoop.hdfs.server.federation.resolver.NamenodeStatusReport;
 import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
 import org.apache.hadoop.security.AccessControlException;
+import org.apache.hadoop.test.GenericTestUtils;
+
+import com.google.common.base.Supplier;
 
 /**
  * Helper utilities for testing HDFS Federation.
@@ -108,33 +110,41 @@ public final class FederationTestUtils {
     return report;
   }
 
-  public static void waitNamenodeRegistered(ActiveNamenodeResolver resolver,
+  /**
-      String nsId, String nnId, FederationNamenodeServiceState finalState)
+   * Wait for a namenode to be registered with a particular state.
-          throws InterruptedException, IllegalStateException, IOException {
+   * @param resolver Active namenode resolver.
-
+   * @param nsId Nameservice identifier.
-    for (int loopCount = 0; loopCount < 20; loopCount++) {
+   * @param nnId Namenode identifier.
-      if (loopCount > 0) {
+   * @param finalState State to check for.
-        Thread.sleep(1000);
+   * @throws Exception Failed to verify State Store registration of namenode
-      }
+   *                   nsId:nnId for state.
+   */
+  public static void waitNamenodeRegistered(
+      final ActiveNamenodeResolver resolver,
+      final String nsId, final String nnId,
+      final FederationNamenodeServiceState state) throws Exception {
 
+    GenericTestUtils.waitFor(new Supplier<Boolean>() {
+      @Override
+      public Boolean get() {
+        try {
           List<? extends FederationNamenodeContext> namenodes =
               resolver.getNamenodesForNameserviceId(nsId);
+          if (namenodes != null) {
             for (FederationNamenodeContext namenode : namenodes) {
               // Check if this is the Namenode we are checking
               if (namenode.getNamenodeId() == nnId  ||
                   namenode.getNamenodeId().equals(nnId)) {
-          if (finalState != null && !namenode.getState().equals(finalState)) {
+                return state == null || namenode.getState().equals(state);
-            // Wrong state, wait a bit more
-            break;
-          } else {
-            // Found and verified
-            return;
               }
             }
           }
+        } catch (IOException e) {
+          // Ignore
         }
-    fail("Failed to verify State Store registration of " + nsId + " " + nnId +
+        return false;
-        " for state " + finalState);
+      }
+    }, 1000, 20 * 1000);
   }
 
   public static boolean verifyDate(Date d1, Date d2, long precision) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/federation/RouterDFSCluster.java

@@ -747,8 +747,7 @@ public class RouterDFSCluster {
     }
   }
 
-  public void waitNamenodeRegistration()
+  public void waitNamenodeRegistration() throws Exception {
-      throws InterruptedException, IllegalStateException, IOException {
     for (RouterContext r : this.routers) {
       Router router = r.router;
       for (NamenodeContext nn : this.namenodes) {
@@ -761,7 +760,7 @@ public class RouterDFSCluster {
 
   public void waitRouterRegistrationQuorum(RouterContext router,
       FederationNamenodeServiceState state, String nsId, String nnId)
-          throws InterruptedException, IOException {
+          throws Exception {
     LOG.info("Waiting for NN {} {} to transition to {}", nsId, nnId, state);
     ActiveNamenodeResolver nnResolver = router.router.getNamenodeResolver();
     waitNamenodeRegistered(nnResolver, nsId, nnId, state);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/federation/resolver/TestMountTableResolver.java

@@ -69,6 +69,7 @@ public class TestMountTableResolver {
    * ______file1.txt -> 4:/user/file1.txt
    * __usr
    * ____bin -> 2:/bin
+   * __readonly -> 2:/tmp
    *
    * @throws IOException If it cannot set the mount table.
    */
@@ -107,6 +108,12 @@ public class TestMountTableResolver {
     // /user/a/demo/test/b
     map = getMountTableEntry("3", "/user/test");
     mountTable.addEntry(MountTable.newInstance("/user/a/demo/test/b", map));
+
+    // /readonly
+    map = getMountTableEntry("2", "/tmp");
+    MountTable readOnlyEntry = MountTable.newInstance("/readonly", map);
+    readOnlyEntry.setReadOnly(true);
+    mountTable.addEntry(readOnlyEntry);
   }
 
   @Before
@@ -152,6 +159,9 @@ public class TestMountTableResolver {
     assertEquals("3->/user/test/a",
         mountTable.getDestinationForPath("/user/test/a").toString());
 
+    assertEquals("2->/tmp/tesfile1.txt",
+        mountTable.getDestinationForPath("/readonly/tesfile1.txt").toString());
+
   }
 
   private void compareLists(List<String> list1, String[] list2) {
@@ -166,8 +176,8 @@ public class TestMountTableResolver {
 
     // Check getting all mount points (virtual and real) beneath a path
     List<String> mounts = mountTable.getMountPoints("/");
-    assertEquals(3, mounts.size());
+    assertEquals(4, mounts.size());
-    compareLists(mounts, new String[] {"tmp", "user", "usr"});
+    compareLists(mounts, new String[] {"tmp", "user", "usr", "readonly"});
 
     mounts = mountTable.getMountPoints("/user");
     assertEquals(2, mounts.size());
@@ -212,9 +222,10 @@ public class TestMountTableResolver {
 
     // Check listing the mount table records at or beneath a path
     List<MountTable> records = mountTable.getMounts("/");
-    assertEquals(8, records.size());
+    assertEquals(9, records.size());
     compareRecords(records, new String[] {"/", "/tmp", "/user", "/usr/bin",
-        "user/a", "/user/a/demo/a", "/user/a/demo/b", "/user/b/file1.txt"});
+        "user/a", "/user/a/demo/a", "/user/a/demo/b", "/user/b/file1.txt",
+        "readonly"});
 
     records = mountTable.getMounts("/user");
     assertEquals(5, records.size());
@@ -229,6 +240,11 @@ public class TestMountTableResolver {
     records = mountTable.getMounts("/tmp");
     assertEquals(1, records.size());
     compareRecords(records, new String[] {"/tmp"});
+
+    records = mountTable.getMounts("/readonly");
+    assertEquals(1, records.size());
+    compareRecords(records, new String[] {"/readonly"});
+    assertTrue(records.get(0).isReadOnly());
   }
 
   @Test
@@ -237,7 +253,7 @@ public class TestMountTableResolver {
 
     // 3 mount points are present /tmp, /user, /usr
     compareLists(mountTable.getMountPoints("/"),
-        new String[] {"user", "usr", "tmp"});
+        new String[] {"user", "usr", "tmp", "readonly"});
 
     // /tmp currently points to namespace 2
     assertEquals("2", mountTable.getDestinationForPath("/tmp/testfile.txt")
@@ -248,7 +264,7 @@ public class TestMountTableResolver {
 
     // Now 2 mount points are present /user, /usr
     compareLists(mountTable.getMountPoints("/"),
-        new String[] {"user", "usr"});
+        new String[] {"user", "usr", "readonly"});
 
     // /tmp no longer exists, uses default namespace for mapping /
     assertEquals("1", mountTable.getDestinationForPath("/tmp/testfile.txt")
@@ -261,7 +277,7 @@ public class TestMountTableResolver {
 
     // 3 mount points are present /tmp, /user, /usr
     compareLists(mountTable.getMountPoints("/"),
-        new String[] {"user", "usr", "tmp"});
+        new String[] {"user", "usr", "tmp", "readonly"});
 
     // /usr is virtual, uses namespace 1->/
     assertEquals("1", mountTable.getDestinationForPath("/usr/testfile.txt")
@@ -272,7 +288,7 @@ public class TestMountTableResolver {
 
     // Verify the remove failed
     compareLists(mountTable.getMountPoints("/"),
-        new String[] {"user", "usr", "tmp"});
+        new String[] {"user", "usr", "tmp", "readonly"});
   }
 
   @Test
@@ -304,7 +320,7 @@ public class TestMountTableResolver {
 
     // Initial table loaded
     testDestination();
-    assertEquals(8, mountTable.getMounts("/").size());
+    assertEquals(9, mountTable.getMounts("/").size());
 
     // Replace table with /1 and /2
     List<MountTable> records = new ArrayList<>();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterAdmin.java

@@ -143,6 +143,37 @@ public class TestRouterAdmin {
     assertFalse(addResponse2.getStatus());
   }
 
+  @Test
+  public void testAddReadOnlyMountTable() throws IOException {
+    MountTable newEntry = MountTable.newInstance(
+        "/readonly", Collections.singletonMap("ns0", "/testdir"),
+        Time.now(), Time.now());
+    newEntry.setReadOnly(true);
+
+    RouterClient client = routerContext.getAdminClient();
+    MountTableManager mountTable = client.getMountTableManager();
+
+    // Existing mount table size
+    List<MountTable> records = getMountTableEntries(mountTable);
+    assertEquals(records.size(), mockMountTable.size());
+
+    // Add
+    AddMountTableEntryRequest addRequest =
+        AddMountTableEntryRequest.newInstance(newEntry);
+    AddMountTableEntryResponse addResponse =
+        mountTable.addMountTableEntry(addRequest);
+    assertTrue(addResponse.getStatus());
+
+    // New mount table size
+    List<MountTable> records2 = getMountTableEntries(mountTable);
+    assertEquals(records2.size(), mockMountTable.size() + 1);
+
+    // Check that we have the read only entry
+    MountTable record = getMountTableEntry("/readonly");
+    assertEquals("/readonly", record.getSourcePath());
+    assertTrue(record.isReadOnly());
+  }
+
   @Test
   public void testRemoveMountTable() throws IOException {
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterMountTable.java

@@ -0,0 +1,143 @@
+/**
+ * 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.server.federation.router;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.IOException;
+import java.util.Collections;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.server.federation.RouterConfigBuilder;
+import org.apache.hadoop.hdfs.server.federation.RouterDFSCluster.NamenodeContext;
+import org.apache.hadoop.hdfs.server.federation.RouterDFSCluster.RouterContext;
+import org.apache.hadoop.hdfs.server.federation.StateStoreDFSCluster;
+import org.apache.hadoop.hdfs.server.federation.resolver.MountTableManager;
+import org.apache.hadoop.hdfs.server.federation.resolver.MountTableResolver;
+import org.apache.hadoop.hdfs.server.federation.store.protocol.AddMountTableEntryRequest;
+import org.apache.hadoop.hdfs.server.federation.store.protocol.AddMountTableEntryResponse;
+import org.apache.hadoop.hdfs.server.federation.store.records.MountTable;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * Test a router end-to-end including the MountTable.
+ */
+public class TestRouterMountTable {
+
+  private static StateStoreDFSCluster cluster;
+  private static NamenodeContext nnContext;
+  private static RouterContext routerContext;
+  private static MountTableResolver mountTable;
+
+  @BeforeClass
+  public static void globalSetUp() throws Exception {
+
+    // Build and start a federated cluster
+    cluster = new StateStoreDFSCluster(false, 1);
+    Configuration conf = new RouterConfigBuilder()
+        .stateStore()
+        .admin()
+        .rpc()
+        .build();
+    cluster.addRouterOverrides(conf);
+    cluster.startCluster();
+    cluster.startRouters();
+    cluster.waitClusterUp();
+
+    // Get the end points
+    nnContext = cluster.getRandomNamenode();
+    routerContext = cluster.getRandomRouter();
+    Router router = routerContext.getRouter();
+    mountTable = (MountTableResolver) router.getSubclusterResolver();
+  }
+
+  @AfterClass
+  public static void tearDown() {
+    if (cluster != null) {
+      cluster.stopRouter(routerContext);
+      cluster.shutdown();
+      cluster = null;
+    }
+  }
+
+  @Test
+  public void testReadOnly() throws Exception {
+
+    // Add a read only entry
+    MountTable readOnlyEntry = MountTable.newInstance(
+        "/readonly", Collections.singletonMap("ns0", "/testdir"));
+    readOnlyEntry.setReadOnly(true);
+    assertTrue(addMountTable(readOnlyEntry));
+
+    // Add a regular entry
+    MountTable regularEntry = MountTable.newInstance(
+        "/regular", Collections.singletonMap("ns0", "/testdir"));
+    assertTrue(addMountTable(regularEntry));
+
+    // Create a folder which should show in all locations
+    final FileSystem nnFs = nnContext.getFileSystem();
+    final FileSystem routerFs = routerContext.getFileSystem();
+    assertTrue(routerFs.mkdirs(new Path("/regular/newdir")));
+
+    FileStatus dirStatusNn =
+        nnFs.getFileStatus(new Path("/testdir/newdir"));
+    assertTrue(dirStatusNn.isDirectory());
+    FileStatus dirStatusRegular =
+        routerFs.getFileStatus(new Path("/regular/newdir"));
+    assertTrue(dirStatusRegular.isDirectory());
+    FileStatus dirStatusReadOnly =
+        routerFs.getFileStatus(new Path("/readonly/newdir"));
+    assertTrue(dirStatusReadOnly.isDirectory());
+
+    // It should fail writing into a read only path
+    try {
+      routerFs.mkdirs(new Path("/readonly/newdirfail"));
+      fail("We should not be able to write into a read only mount point");
+    } catch (IOException ioe) {
+      String msg = ioe.getMessage();
+      assertTrue(msg.startsWith(
+          "/readonly/newdirfail is in a read only mount point"));
+    }
+  }
+
+  /**
+   * Add a mount table entry to the mount table through the admin API.
+   * @param entry Mount table entry to add.
+   * @return If it was succesfully added.
+   * @throws IOException Problems adding entries.
+   */
+  private boolean addMountTable(final MountTable entry) throws IOException {
+    RouterClient client = routerContext.getAdminClient();
+    MountTableManager mountTableManager = client.getMountTableManager();
+    AddMountTableEntryRequest addRequest =
+        AddMountTableEntryRequest.newInstance(entry);
+    AddMountTableEntryResponse addResponse =
+        mountTableManager.addMountTableEntry(addRequest);
+
+    // Reload the Router cache
+    mountTable.loadCache(true);
+
+    return addResponse.getStatus();
+  }
+}