@Test
  public void testGetTokensForNamenodes() throws IOException {

    Credentials credentials = new Credentials();
    TokenCache.obtainTokensForNamenodesInternal(credentials, new Path[] {p1, p2}, jConf);

    // this token is keyed by hostname:port key.
    String fs_addr = SecurityUtil.buildDTServiceName(p1.toUri(), NameNode.DEFAULT_PORT);
    Token<DelegationTokenIdentifier> nnt = TokenCache.getDelegationToken(credentials, fs_addr);
    System.out.println("dt for " + p1 + "(" + fs_addr + ")" + " = " + nnt);
    assertNotNull("Token for nn is null", nnt);

    // verify the size
    Collection<Token<? extends TokenIdentifier>> tns = credentials.getAllTokens();
    assertEquals("number of tokens is not 1", 1, tns.size());

    boolean found = false;
    for (Token<? extends TokenIdentifier> t : tns) {
      if (t.getKind().equals(DelegationTokenIdentifier.HDFS_DELEGATION_KIND)
          && t.getService().equals(new Text(fs_addr))) {
        found = true;
      }
      assertTrue("didn't find token for " + p1, found);
    }
  }
  @Test
  public void testGetTokensForViewFS() throws IOException, URISyntaxException {
    Configuration conf = new Configuration(jConf);
    FileSystem dfs = dfsCluster.getFileSystem();
    String serviceName = dfs.getCanonicalServiceName();

    Path p1 = new Path("/mount1");
    Path p2 = new Path("/mount2");
    p1 = dfs.makeQualified(p1);
    p2 = dfs.makeQualified(p2);

    conf.set("fs.viewfs.mounttable.default.link./dir1", p1.toString());
    conf.set("fs.viewfs.mounttable.default.link./dir2", p2.toString());
    Credentials credentials = new Credentials();
    Path lp1 = new Path("viewfs:///dir1");
    Path lp2 = new Path("viewfs:///dir2");
    Path[] paths = new Path[2];
    paths[0] = lp1;
    paths[1] = lp2;
    TokenCache.obtainTokensForNamenodesInternal(credentials, paths, conf);

    Collection<Token<? extends TokenIdentifier>> tns = credentials.getAllTokens();
    assertEquals("number of tokens is not 1", 1, tns.size());

    boolean found = false;
    for (Token<? extends TokenIdentifier> tt : tns) {
      System.out.println("token=" + tt);
      if (tt.getKind().equals(DelegationTokenIdentifier.HDFS_DELEGATION_KIND)
          && tt.getService().equals(new Text(serviceName))) {
        found = true;
      }
      assertTrue("didn't find token for [" + lp1 + ", " + lp2 + "]", found);
    }
  }
Esempio n. 3
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 /**
  * Obtain the tokens needed by the job and put them in the UGI
  *
  * @param conf
  */
 protected void downloadTokensAndSetupUGI(Configuration conf) {
   try {
     this.currentUser = UserGroupInformation.getCurrentUser();
     if (UserGroupInformation.isSecurityEnabled()) {
       // Read the file-system tokens from the localized tokens-file.
       Path jobSubmitDir =
           FileContext.getLocalFSFileContext()
               .makeQualified(
                   new Path(new File(DragonJobConfig.JOB_SUBMIT_DIR).getAbsolutePath()));
       Path jobTokenFile = new Path(jobSubmitDir, DragonJobConfig.APPLICATION_TOKENS_FILE);
       fsTokens.addAll(Credentials.readTokenStorageFile(jobTokenFile, conf));
       LOG.info("jobSubmitDir=" + jobSubmitDir + " jobTokenFile=" + jobTokenFile);
       for (Token<? extends TokenIdentifier> tk : fsTokens.getAllTokens()) {
         if (LOG.isDebugEnabled()) {
           LOG.debug(
               "Token of kind "
                   + tk.getKind()
                   + "in current ugi in the AppMaster for service "
                   + tk.getService());
         }
         currentUser.addToken(tk); // For use by AppMaster itself.
       }
     }
   } catch (IOException e) {
     throw new YarnException(e);
   }
 }
Esempio n. 4
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 private void addTimelineDelegationToken(ContainerLaunchContext clc)
     throws YarnException, IOException {
   Credentials credentials = new Credentials();
   DataInputByteBuffer dibb = new DataInputByteBuffer();
   ByteBuffer tokens = clc.getTokens();
   if (tokens != null) {
     dibb.reset(tokens);
     credentials.readTokenStorageStream(dibb);
     tokens.rewind();
   }
   // If the timeline delegation token is already in the CLC, no need to add
   // one more
   for (org.apache.hadoop.security.token.Token<? extends TokenIdentifier> token :
       credentials.getAllTokens()) {
     if (token.getKind().equals(TimelineDelegationTokenIdentifier.KIND_NAME)) {
       return;
     }
   }
   org.apache.hadoop.security.token.Token<TimelineDelegationTokenIdentifier>
       timelineDelegationToken = getTimelineDelegationToken();
   if (timelineDelegationToken == null) {
     return;
   }
   credentials.addToken(timelineService, timelineDelegationToken);
   if (LOG.isDebugEnabled()) {
     LOG.debug("Add timline delegation token into credentials: " + timelineDelegationToken);
   }
   DataOutputBuffer dob = new DataOutputBuffer();
   credentials.writeTokenStorageToStream(dob);
   tokens = ByteBuffer.wrap(dob.getData(), 0, dob.getLength());
   clc.setTokens(tokens);
 }
  /**
   * Load Hadoop Job Token into secret manager.
   *
   * @param conf Configuration
   * @throws IOException
   */
  private void setupSecretManager(Configuration conf) throws IOException {
    secretManager = new JobTokenSecretManager();
    String localJobTokenFile = System.getenv().get(UserGroupInformation.HADOOP_TOKEN_FILE_LOCATION);
    if (localJobTokenFile == null) {
      throw new IOException(
          "Could not find job credentials: environment "
              + "variable: "
              + UserGroupInformation.HADOOP_TOKEN_FILE_LOCATION
              + " was not defined.");
    }
    JobConf jobConf = new JobConf(conf);

    // Find the JobTokenIdentifiers among all the tokens available in the
    // jobTokenFile and store them in the secretManager.
    Credentials credentials = TokenCache.loadTokens(localJobTokenFile, jobConf);
    Collection<Token<? extends TokenIdentifier>> collection = credentials.getAllTokens();
    for (Token<? extends TokenIdentifier> token : collection) {
      TokenIdentifier tokenIdentifier = decodeIdentifier(token, JobTokenIdentifier.class);
      if (tokenIdentifier instanceof JobTokenIdentifier) {
        Token<JobTokenIdentifier> theToken = (Token<JobTokenIdentifier>) token;
        JobTokenIdentifier jobTokenIdentifier = (JobTokenIdentifier) tokenIdentifier;
        secretManager.addTokenForJob(jobTokenIdentifier.getJobId().toString(), theToken);
      }
    }
    if (LOG.isDebugEnabled()) {
      LOG.debug(
          "loaded JobToken credentials: "
              + credentials
              + " from "
              + "localJobTokenFile: "
              + localJobTokenFile);
    }
  }
  @SuppressWarnings("unchecked")
  public static synchronized void registerDelegationTokensForRenewal(
      JobID jobId, Credentials ts, Configuration conf) {
    if (ts == null) return; // nothing to add

    Collection<Token<? extends TokenIdentifier>> tokens = ts.getAllTokens();
    long now = System.currentTimeMillis();

    for (Token<? extends TokenIdentifier> t : tokens) {
      // currently we only check for HDFS delegation tokens
      // later we can add more different types.
      if (!t.getKind().equals(kindHdfs)) {
        continue;
      }
      Token<DelegationTokenIdentifier> dt = (Token<DelegationTokenIdentifier>) t;

      // first renew happens immediately
      DelegationTokenToRenew dtr = new DelegationTokenToRenew(jobId, dt, conf, now);

      addTokenToList(dtr);

      setTimerForTokenRenewal(dtr, true);
      LOG.info(
          "registering token for renewal for service ="
              + dt.getService()
              + " and jobID = "
              + jobId);
    }
  }
  private void handleAppSubmitEvent(DelegationTokenRenewerAppSubmitEvent evt)
      throws IOException, InterruptedException {
    ApplicationId applicationId = evt.getApplicationId();
    Credentials ts = evt.getCredentials();
    boolean shouldCancelAtEnd = evt.shouldCancelAtEnd();
    if (ts == null) {
      return; // nothing to add
    }

    if (LOG.isDebugEnabled()) {
      LOG.debug("Registering tokens for renewal for:" + " appId = " + applicationId);
    }

    Collection<Token<?>> tokens = ts.getAllTokens();
    long now = System.currentTimeMillis();

    // find tokens for renewal, but don't add timers until we know
    // all renewable tokens are valid
    // At RM restart it is safe to assume that all the previously added tokens
    // are valid
    appTokens.put(
        applicationId, Collections.synchronizedSet(new HashSet<DelegationTokenToRenew>()));
    Set<DelegationTokenToRenew> tokenList = new HashSet<DelegationTokenToRenew>();
    boolean hasHdfsToken = false;
    for (Token<?> token : tokens) {
      if (token.isManaged()) {
        tokenList.add(
            new DelegationTokenToRenew(
                applicationId, token, getConfig(), now, shouldCancelAtEnd, evt.getUser()));
        if (token.getKind().equals(new Text("HDFS_DELEGATION_TOKEN"))) {
          LOG.info(applicationId + " found existing hdfs token " + token);
          hasHdfsToken = true;
        }
      }
    }

    if (!tokenList.isEmpty()) {
      // Renewing token and adding it to timer calls are separated purposefully
      // If user provides incorrect token then it should not be added for
      // renewal.
      for (DelegationTokenToRenew dtr : tokenList) {
        try {
          renewToken(dtr);
        } catch (IOException ioe) {
          throw new IOException("Failed to renew token: " + dtr.token, ioe);
        }
      }
      for (DelegationTokenToRenew dtr : tokenList) {
        appTokens.get(applicationId).add(dtr);
        setTimerForTokenRenewal(dtr);
      }
    }

    if (!hasHdfsToken) {
      requestNewHdfsDelegationToken(applicationId, evt.getUser(), shouldCancelAtEnd);
    }
  }
 private Token<? extends TokenIdentifier> generateDelegationToken(
     final NameNode namenode, final UserGroupInformation ugi, final String renewer)
     throws IOException {
   final Credentials c =
       DelegationTokenSecretManager.createCredentials(
           namenode, ugi, renewer != null ? renewer : ugi.getShortUserName());
   final Token<? extends TokenIdentifier> t = c.getAllTokens().iterator().next();
   t.setKind(WebHdfsFileSystem.TOKEN_KIND);
   SecurityUtil.setTokenService(t, namenode.getHttpAddress());
   return t;
 }
Esempio n. 9
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 private void printTokens(JobID jobId, Credentials credentials) throws IOException {
   if (LOG.isDebugEnabled()) {
     LOG.debug("Printing tokens for job: " + jobId);
     for (Token<?> token : credentials.getAllTokens()) {
       if (token.getKind().toString().equals("HDFS_DELEGATION_TOKEN")) {
         LOG.debug(
             "Submitting with "
                 + org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier
                     .stringifyToken(token));
       }
     }
   }
 }
 private void populateTokens(Job job) {
   // Credentials in the job will not have delegation tokens
   // because security is disabled. Fetch delegation tokens
   // and populate the credential in the job.
   try {
     Credentials ts = job.getCredentials();
     Path p1 = new Path("file1");
     p1 = p1.getFileSystem(job.getConfiguration()).makeQualified(p1);
     Credentials cred = new Credentials();
     TokenCache.obtainTokensForNamenodesInternal(cred, new Path[] {p1}, job.getConfiguration());
     for (Token<? extends TokenIdentifier> t : cred.getAllTokens()) {
       ts.addToken(new Text("Hdfs"), t);
     }
   } catch (IOException e) {
     Assert.fail("Exception " + e);
   }
 }
    /** attempts to access tokenCache as from client */
    @Override
    public void map(IntWritable key, IntWritable value, Context context)
        throws IOException, InterruptedException {
      // get token storage and a key
      Credentials ts = context.getCredentials();
      byte[] key1 = ts.getSecretKey(new Text("alias1"));
      Collection<Token<? extends TokenIdentifier>> dts = ts.getAllTokens();
      int dts_size = 0;
      if (dts != null) dts_size = dts.size();

      if (dts_size != 2) { // one job token and one delegation token
        throw new RuntimeException("tokens are not available"); // fail the test
      }

      if (key1 == null || ts == null || ts.numberOfSecretKeys() != NUM_OF_KEYS) {
        throw new RuntimeException("secret keys are not available"); // fail the test
      }
      super.map(key, value, context);
    }
  public static Credentials getDTfromRemote(String nnAddr, String renewer) throws IOException {
    DataInputStream dis = null;

    try {
      StringBuffer url = new StringBuffer();
      if (renewer != null) {
        url.append(nnAddr)
            .append(GetDelegationTokenServlet.PATH_SPEC)
            .append("?")
            .append(GetDelegationTokenServlet.RENEWER)
            .append("=")
            .append(renewer);
      } else {
        url.append(nnAddr).append(GetDelegationTokenServlet.PATH_SPEC);
      }

      if (LOG.isDebugEnabled()) {
        LOG.debug("Retrieving token from: " + url);
      }

      URL remoteURL = new URL(url.toString());
      SecurityUtil.fetchServiceTicket(remoteURL);
      URLConnection connection = remoteURL.openConnection();

      InputStream in = connection.getInputStream();
      Credentials ts = new Credentials();
      dis = new DataInputStream(in);
      ts.readFields(dis);
      for (Token<?> token : ts.getAllTokens()) {
        token.setKind(HftpFileSystem.TOKEN_KIND);
        token.setService(
            new Text(
                SecurityUtil.buildDTServiceName(
                    remoteURL.toURI(), DFSConfigKeys.DFS_HTTPS_PORT_DEFAULT)));
      }
      return ts;
    } catch (Exception e) {
      throw new IOException("Unable to obtain remote token", e);
    } finally {
      if (dis != null) dis.close();
    }
  }
Esempio n. 13
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  private ByteBuffer getSecurityTokens() throws IOException {
    Credentials credentials = UserGroupInformation.getCurrentUser().getCredentials();
    Closer closer = Closer.create();
    try {
      DataOutputBuffer dataOutputBuffer = closer.register(new DataOutputBuffer());
      credentials.writeTokenStorageToStream(dataOutputBuffer);

      // Remove the AM->RM token so that containers cannot access it
      Iterator<Token<?>> tokenIterator = credentials.getAllTokens().iterator();
      while (tokenIterator.hasNext()) {
        Token<?> token = tokenIterator.next();
        if (token.getKind().equals(AMRMTokenIdentifier.KIND_NAME)) {
          tokenIterator.remove();
        }
      }

      return ByteBuffer.wrap(dataOutputBuffer.getData(), 0, dataOutputBuffer.getLength());
    } catch (Throwable t) {
      throw closer.rethrow(t);
    } finally {
      closer.close();
    }
  }
 private static Collection<Token<?>> readTokens(Path file, Configuration conf) throws IOException {
   Credentials creds = Credentials.readTokenStorageFile(file, conf);
   return creds.getAllTokens();
 }
Esempio n. 15
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  @Test
  public void testAutomaticTimelineDelegationTokenLoading() throws Exception {
    Configuration conf = new YarnConfiguration();
    conf.setBoolean(YarnConfiguration.TIMELINE_SERVICE_ENABLED, true);
    SecurityUtil.setAuthenticationMethod(AuthenticationMethod.KERBEROS, conf);
    TimelineDelegationTokenIdentifier timelineDT = new TimelineDelegationTokenIdentifier();
    final Token<TimelineDelegationTokenIdentifier> dToken =
        new Token<TimelineDelegationTokenIdentifier>(
            timelineDT.getBytes(), new byte[0], timelineDT.getKind(), new Text());
    // crate a mock client
    YarnClientImpl client =
        spy(
            new YarnClientImpl() {
              @Override
              protected void serviceInit(Configuration conf) throws Exception {
                if (getConfig()
                    .getBoolean(
                        YarnConfiguration.TIMELINE_SERVICE_ENABLED,
                        YarnConfiguration.DEFAULT_TIMELINE_SERVICE_ENABLED)) {
                  timelineServiceEnabled = true;
                  timelineClient = mock(TimelineClient.class);
                  when(timelineClient.getDelegationToken(any(String.class))).thenReturn(dToken);
                  timelineClient.init(getConfig());
                  timelineService = TimelineUtils.buildTimelineTokenService(getConfig());
                }
                this.setConfig(conf);
              }

              @Override
              protected void serviceStart() throws Exception {
                rmClient = mock(ApplicationClientProtocol.class);
              }

              @Override
              protected void serviceStop() throws Exception {}

              @Override
              public ApplicationReport getApplicationReport(ApplicationId appId) {
                ApplicationReport report = mock(ApplicationReport.class);
                when(report.getYarnApplicationState()).thenReturn(YarnApplicationState.SUBMITTED);
                return report;
              }

              @Override
              public boolean isSecurityEnabled() {
                return true;
              }
            });
    client.init(conf);
    client.start();
    try {
      // when i == 0, timeline DT already exists, no need to get one more
      // when i == 1, timeline DT doesn't exist, need to get one more
      for (int i = 0; i < 2; ++i) {
        ApplicationSubmissionContext context = mock(ApplicationSubmissionContext.class);
        ApplicationId applicationId = ApplicationId.newInstance(0, i + 1);
        when(context.getApplicationId()).thenReturn(applicationId);
        DataOutputBuffer dob = new DataOutputBuffer();
        Credentials credentials = new Credentials();
        if (i == 0) {
          credentials.addToken(client.timelineService, dToken);
        }
        credentials.writeTokenStorageToStream(dob);
        ByteBuffer tokens = ByteBuffer.wrap(dob.getData(), 0, dob.getLength());
        ContainerLaunchContext clc =
            ContainerLaunchContext.newInstance(null, null, null, null, tokens, null);
        when(context.getAMContainerSpec()).thenReturn(clc);
        client.submitApplication(context);
        if (i == 0) {
          // GetTimelineDelegationToken shouldn't be called
          verify(client, never()).getTimelineDelegationToken();
        }
        // In either way, token should be there
        credentials = new Credentials();
        DataInputByteBuffer dibb = new DataInputByteBuffer();
        tokens = clc.getTokens();
        if (tokens != null) {
          dibb.reset(tokens);
          credentials.readTokenStorageStream(dibb);
          tokens.rewind();
        }
        Collection<Token<? extends TokenIdentifier>> dTokens = credentials.getAllTokens();
        Assert.assertEquals(1, dTokens.size());
        Assert.assertEquals(dToken, dTokens.iterator().next());
      }
    } finally {
      client.stop();
    }
  }
  /**
   * Main run function for the application master
   *
   * @throws YarnException
   * @throws IOException
   */
  @SuppressWarnings({"unchecked"})
  public void run() throws YarnException, IOException {
    LOG.info("Starting ApplicationMaster");
    try {
      publishApplicationAttemptEvent(
          timelineClient, appAttemptID.toString(), DSEvent.DS_APP_ATTEMPT_START);
    } catch (Exception e) {
      LOG.error("App Attempt start event coud not be pulished for " + appAttemptID.toString(), e);
    }

    Credentials credentials = UserGroupInformation.getCurrentUser().getCredentials();
    DataOutputBuffer dob = new DataOutputBuffer();
    credentials.writeTokenStorageToStream(dob);
    // Now remove the AM->RM token so that containers cannot access it.
    Iterator<Token<?>> iter = credentials.getAllTokens().iterator();
    LOG.info("Executing with tokens:");
    while (iter.hasNext()) {
      Token<?> token = iter.next();
      LOG.info(token);
      if (token.getKind().equals(AMRMTokenIdentifier.KIND_NAME)) {
        iter.remove();
      }
    }
    allTokens = ByteBuffer.wrap(dob.getData(), 0, dob.getLength());

    // Create appSubmitterUgi and add original tokens to it
    String appSubmitterUserName = System.getenv(ApplicationConstants.Environment.USER.name());
    appSubmitterUgi = UserGroupInformation.createRemoteUser(appSubmitterUserName);
    appSubmitterUgi.addCredentials(credentials);

    AMRMClientAsync.CallbackHandler allocListener = new RMCallbackHandler();
    amRMClient = AMRMClientAsync.createAMRMClientAsync(1000, allocListener);
    amRMClient.init(conf);
    amRMClient.start();

    containerListener = createNMCallbackHandler();
    nmClientAsync = new NMClientAsyncImpl(containerListener);
    nmClientAsync.init(conf);
    nmClientAsync.start();

    // Setup local RPC Server to accept status requests directly from clients
    // TODO need to setup a protocol for client to be able to communicate to
    // the RPC server
    // TODO use the rpc port info to register with the RM for the client to
    // send requests to this app master

    // Register self with ResourceManager
    // This will start heartbeating to the RM
    appMasterHostname = NetUtils.getHostname();
    RegisterApplicationMasterResponse response =
        amRMClient.registerApplicationMaster(
            appMasterHostname, appMasterRpcPort, appMasterTrackingUrl);
    // Dump out information about cluster capability as seen by the
    // resource manager
    int maxMem = response.getMaximumResourceCapability().getMemory();
    LOG.info("Max mem capabililty of resources in this cluster " + maxMem);

    int maxVCores = response.getMaximumResourceCapability().getVirtualCores();
    LOG.info("Max vcores capabililty of resources in this cluster " + maxVCores);

    // A resource ask cannot exceed the max.
    if (containerMemory > maxMem) {
      LOG.info(
          "Container memory specified above max threshold of cluster."
              + " Using max value."
              + ", specified="
              + containerMemory
              + ", max="
              + maxMem);
      containerMemory = maxMem;
    }

    if (containerVirtualCores > maxVCores) {
      LOG.info(
          "Container virtual cores specified above max threshold of cluster."
              + " Using max value."
              + ", specified="
              + containerVirtualCores
              + ", max="
              + maxVCores);
      containerVirtualCores = maxVCores;
    }

    List<Container> previousAMRunningContainers = response.getContainersFromPreviousAttempts();
    LOG.info(
        "Received "
            + previousAMRunningContainers.size()
            + " previous AM's running containers on AM registration.");
    numAllocatedContainers.addAndGet(previousAMRunningContainers.size());

    int numTotalContainersToRequest = numTotalContainers - previousAMRunningContainers.size();
    // Setup ask for containers from RM
    // Send request for containers to RM
    // Until we get our fully allocated quota, we keep on polling RM for
    // containers
    // Keep looping until all the containers are launched and shell script
    // executed on them ( regardless of success/failure).
    for (int i = 0; i < numTotalContainersToRequest; ++i) {
      ContainerRequest containerAsk = setupContainerAskForRM();
      amRMClient.addContainerRequest(containerAsk);
    }
    numRequestedContainers.set(numTotalContainersToRequest);
    try {
      publishApplicationAttemptEvent(
          timelineClient, appAttemptID.toString(), DSEvent.DS_APP_ATTEMPT_END);
    } catch (Exception e) {
      LOG.error("App Attempt start event coud not be pulished for " + appAttemptID.toString(), e);
    }
  }
  @Test
  public void testGetTokensForHftpFS() throws IOException, URISyntaxException {
    HftpFileSystem hfs = mock(HftpFileSystem.class);

    DelegationTokenSecretManager dtSecretManager =
        NameNodeAdapter.getDtSecretManager(dfsCluster.getNamesystem());
    String renewer = "renewer";
    jConf.set(JTConfig.JT_USER_NAME, renewer);
    DelegationTokenIdentifier dtId =
        new DelegationTokenIdentifier(new Text("user"), new Text(renewer), null);
    final Token<DelegationTokenIdentifier> t =
        new Token<DelegationTokenIdentifier>(dtId, dtSecretManager);

    final URI uri = new URI("hftp://host:2222/file1");
    final String fs_addr = SecurityUtil.buildDTServiceName(uri, NameNode.DEFAULT_PORT);
    t.setService(new Text(fs_addr));

    // when(hfs.getUri()).thenReturn(uri);
    Mockito.doAnswer(
            new Answer<URI>() {
              @Override
              public URI answer(InvocationOnMock invocation) throws Throwable {
                return uri;
              }
            })
        .when(hfs)
        .getUri();

    // when(hfs.getDelegationToken()).thenReturn((Token<? extends TokenIdentifier>) t);
    Mockito.doAnswer(
            new Answer<Token<DelegationTokenIdentifier>>() {
              @Override
              public Token<DelegationTokenIdentifier> answer(InvocationOnMock invocation)
                  throws Throwable {
                return t;
              }
            })
        .when(hfs)
        .getDelegationToken(renewer);

    // when(hfs.getDelegationTokens()).thenReturn((Token<? extends TokenIdentifier>) t);
    Mockito.doAnswer(
            new Answer<List<Token<DelegationTokenIdentifier>>>() {
              @Override
              public List<Token<DelegationTokenIdentifier>> answer(InvocationOnMock invocation)
                  throws Throwable {
                return Collections.singletonList(t);
              }
            })
        .when(hfs)
        .getDelegationTokens(renewer);

    // when(hfs.getCanonicalServiceName).thenReturn(fs_addr);
    Mockito.doAnswer(
            new Answer<String>() {
              @Override
              public String answer(InvocationOnMock invocation) throws Throwable {
                return fs_addr;
              }
            })
        .when(hfs)
        .getCanonicalServiceName();

    Credentials credentials = new Credentials();
    Path p = new Path(uri.toString());
    System.out.println("Path for hftp=" + p + "; fs_addr=" + fs_addr + "; rn=" + renewer);
    TokenCache.obtainTokensForNamenodesInternal(hfs, credentials, jConf);

    Collection<Token<? extends TokenIdentifier>> tns = credentials.getAllTokens();
    assertEquals("number of tokens is not 1", 1, tns.size());

    boolean found = false;
    for (Token<? extends TokenIdentifier> tt : tns) {
      System.out.println("token=" + tt);
      if (tt.getKind().equals(DelegationTokenIdentifier.HDFS_DELEGATION_KIND)
          && tt.getService().equals(new Text(fs_addr))) {
        found = true;
        assertEquals("different token", tt, t);
      }
      assertTrue("didn't find token for " + p, found);
    }
  }