前往小程序，Get更优阅读体验！
立即前往
文档建议反馈控制台
首页
学习
活动
专区
工具
TVP
最新优惠活动
文章/答案/技术大牛
发布
首页
学习
活动
专区
工具
TVP最新优惠活动
返回腾讯云官网
社区首页 >专栏 >一文讲透hdfs的delegation token

一文讲透hdfs的delegation token

作者头像
陈猿解码
发布于 2023-02-28 15:04:37
1.7K3
发布于 2023-02-28 15:04:37
举报
文章被收录于专栏：陈猿解码

【背景】

前一段时间总结了hadoop中的token认证、yarn任务运行中的token，其中也都提到了delegation token。而最近也遇到了一个问题，问题现象是：flink任务运行超过七天后，由于宿主机异常导致任务失败，继而触发任务的重试，但接连重试几次都是失败的，并且任务的日志也没有聚合，导致无法分析问题失败的原因。最后发现是和delegation token有关，本文就来总结下相关的原理。

【原理】

1. 什么是delegation token

先简单描述下为什么需要delegation token。在开启kerberos之后，服务之间交互前，都需要先向KDC认证获取对应的票据。而在一个yarn任务运行过程中可能会产生很多任务container，每个这样的任务container都可能会访问hdfs，由于访问前需要先获取票据来进行认证，那么这个时候KDC就很容易成为性能瓶颈。delegation token（委派token）就是为了减少不必要的认证工作而出现的。

2. delegation token在任务提交运行过程中的使用

任务提交运行过程中，delegation token相关的流程如下图所示：

1）首先，RM启动后，内部会创建一个服务线程专门用于处理token的更新

代码语言：javascript
复制
// ResourceManager.java
protected void serviceInit(Configuration configuration) throws Exception {
    ...
    if (UserGroupInformation.isSecurityEnabled()) {
        delegationTokenRenewer = createDelegationTokenRenewer();
        rmContext.setDelegationTokenRenewer(delegationTokenRenewer);
    }
    ....
}

protected DelegationTokenRenewer createDelegationTokenRenewer() {
    return new DelegationTokenRenewer();
}

2）客户端申请delegation token

客户端在提交任务前，通常需要先向hdfs上传资源文件（包括运行所需的jar包等），在此过程中会向nn申请一个delegation token，并放到任务启动上下文中，然后向rm发送提交任务请求（请求中包含任务的启动上下文）。

下面是flink on yarn提交任务时的代码片段：

代码语言：javascript
复制
// flink YarnClusterDescriptor.java
private ApplicationReport startAppMaster(...){
    // 开启kerberos的情况下，获取token
    if (UserGroupInformation.isSecurityEnabled()) {
      // set HDFS delegation tokens when security is enabled
      LOG.info("Adding delegation token to the AM container.");
      List<Path> yarnAccessList =
        ConfigUtils.decodeListFromConfig(
          configuration, YarnConfigOptions.YARN_ACCESS, Path::new);
      Utils.setTokensFor(
        amContainer,
        ListUtils.union(yarnAccessList, fileUploader.getRemotePaths()),
        yarnConfiguration);
    }
}

public static void setTokensFor(
    ContainerLaunchContext amContainer, List<Path> paths, Configuration conf)
    throws IOException {
    Credentials credentials = new Credentials();
    // for HDFS
    TokenCache.obtainTokensForNamenodes(credentials, paths.toArray(new Path[0]), conf);
    // for HBase
    obtainTokenForHBase(credentials, conf);
    // for user
    UserGroupInformation currUsr = UserGroupInformation.getCurrentUser();
    // 获取到的token 放到启动上下文中
    Collection<Token<? extends TokenIdentifier>> usrTok = currUsr.getTokens();
    for (Token<? extends TokenIdentifier> token : usrTok) {
        final Text id = new Text(token.getIdentifier());
        LOG.info("Adding user token " + id + " with " + token);
        credentials.addToken(id, token);
    }
    try (DataOutputBuffer dob = new DataOutputBuffer()) {
        credentials.writeTokenStorageToStream(dob);

        if (LOG.isDebugEnabled()) {
            LOG.debug("Wrote tokens. Credentials buffer length: " + dob.getLength());
        }

        ByteBuffer securityTokens = ByteBuffer.wrap(dob.getData(), 0, dob.getLength());
        amContainer.setTokens(securityTokens);
    }
}

// TokenCache.java
// 调用hadoop的接口 向nn请求token
public static void obtainTokensForNamenodes(
    Credentials credentials,
    Path[] ps, Configuration conf) 
    throws IOException {
    if (!UserGroupInformation.isSecurityEnabled()) {
        return;
    }
    obtainTokensForNamenodesInternal(credentials, ps, conf);
}

static void obtainTokensForNamenodesInternal(
    Credentials credentials,
    Path[] ps, 
    Configuration conf) 
    throws IOException {
    Set<FileSystem> fsSet = new HashSet<FileSystem>();
    for (Path p : ps) {
        fsSet.add(p.getFileSystem(conf));
    }
    String masterPrincipal = Master.getMasterPrincipal(conf);
    for (FileSystem fs : fsSet) {
        obtainTokensForNamenodesInternal(fs, credentials, conf, masterPrincipal);
    }
}

static void obtainTokensForNamenodesInternal(
    FileSystem fs,
    Credentials credentials, 
    Configuration conf, 
    String renewer)
    throws IOException {
    ...
    final Token<?> tokens[] = fs.addDelegationTokens(delegTokenRenewer, credentials);
    ...
}

// FileSystem.java
public Token<?>[] addDelegationTokens(
    final String renewer, Credentials credentials) 
    throws IOException {
    if (credentials == null) {
        credentials = new Credentials();
    }
    final List<Token<?>> tokens = new ArrayList<>();
    collectDelegationTokens(renewer, credentials, tokens);
    return tokens.toArray(new Token<?>[tokens.size()]);
}

private void collectDelegationTokens(
    final String renewer,
    final Credentials credentials,
    final List<Token<?>> tokens)
    throws IOException {
    final String serviceName = getCanonicalServiceName();
    // Collect token of the this filesystem and then of its embedded children
    if (serviceName != null) { // fs has token, grab it
        final Text service = new Text(serviceName);
        Token<?> token = credentials.getToken(service);
        if (token == null) {
            // 向NN 请求delegation token
            token = getDelegationToken(renewer);
            if (token != null) {
                tokens.add(token);
                credentials.addToken(service, token);
            }
        }
    }
    ...
}

3）RM将token添加到delegation token更新服务中

RM在处理客户端提交任务请求时，判断是否启用kerberos认证，如果启用则从任务启动上下文中解析出delegation token，并添加到delegation token更新服务中。在该服务中，会启动线程定时对delegation token进行更新。此后，继续向NM发送启动container的请求，delegation token则随启动上下文被带到NM中。

代码语言：javascript
复制
// RMAppManager.java
protected void submitApplication(
    ApplicationSubmissionContext submissionContext, 
    long submitTime,
    String user)
    throws YarnException {
    ...
    if (UserGroupInformation.isSecurityEnabled()) {
        this.rmContext.getDelegationTokenRenewer().addApplicationAsync(
            applicationId,
            BuilderUtils.parseCredentials(submissionContext),
            submissionContext.getCancelTokensWhenComplete(),
            application.getUser(),
            BuilderUtils.parseTokensConf(submissionContext));
    }
    ...
}

4）NM使用delegation token

NM收到启动container的请求后，从请求（任务启动上下文）中解析出delegation token，并为该container构造一个对应的实例对象，同时将delegation token保存在该实例对象中，然后为该container进行资源本地化，即从hdfs中下载必须的资源文件，这里就会用到传递过来的delegation token。同时在任务结束时，如果需要进行任务日志聚合，仍旧会使用该delegation token将任务的日志上传到hdfs的指定路径。

另外，delegation token还会写入到持久化文件中，一方面用于NM的异常恢复，另一方面是将token传递给任务container进程以供使用。

3. delegation token的更新与生命周期

1）申请token时已经指定了token的最大生命周期

代码语言：javascript
复制
// FSNamesystem.java
Token<DelegationTokenIdentifier> getDelegationToken(Text renewer) throws IOException {
    ...
    DelegationTokenIdentifier dtId = new DelegationTokenIdentifier(owner, renewer, realUser);
    token = new Token<DelegationTokenIdentifier>(dtId, dtSecretManager);
    ...
    return token;
}

// Token.java
public Token(T id, SecretManager<T> mgr) {
    password = mgr.createPassword(id);
    identifier = id.getBytes();
    kind = id.getKind();
    service = new Text();
}

// AbstractDelegationTokenSecretManager
protected synchronized byte[] createPassword(TokenIdent identifier) {
    long now = Time.now();
    identifier.setMaxDate(now + tokenMaxLifetime);
    ...
}

2）RM接收到任务提交请求后，先进行一次更新得到token的下次超时时间，然后再根据超时时间设置定时器时间触发进行更新。

代码语言：javascript
复制
public void addApplicationSync(
    ApplicationId applicationId, 
    Credentials ts,
    boolean shouldCancelAtEnd, 
    String user) 
    throws IOException, InterruptedException {
    handleAppSubmitEvent(
        new DelegationTokenRenewerAppSubmitEvent(
            applicationId, ts, shouldCancelAtEnd, user, new Configuration()));
}

private void handleAppSubmitEvent(AbstractDelegationTokenRenewerAppEvent evt)
    throws IOException, InterruptedException {
    ...
    Credentials ts = evt.getCredentials();
    Collection<Token<?>> tokens = ts.getAllTokens();
    for (Token<?> token : tokens) {
        DelegationTokenToRenew dttr = allTokens.get(token);
        if (dttr == null) {
            dttr = new DelegationTokenToRenew(
                Arrays.asList(applicationId), 
                token, tokenConf, now, shouldCancelAtEnd, 
                evt.getUser());
            try {
                // 先进行一次更新
                renewToken(dttr)
            } catch (IOException ioe) {
                ...
            }
        }
        tokenList.add(dttr);
    }
    
    if (!tokenList.isEmpty()) {
        for (DelegationTokenToRenew dtr : tokenList) {
            DelegationTokenToRenew currentDtr = allTokens.putIfAbsent(dtr.token, dtr);
            if (currentDtr != null) {
                // another job beat us
                currentDtr.referringAppIds.add(applicationId);
                appTokens.get(applicationId).add(currentDtr);
            } else {
                appTokens.get(applicationId).add(dtr);
                setTimerForTokenRenewal(dtr);
            }
        }
    }
}

protected void renewToken(final DelegationTokenToRenew dttr)
    throws IOException {
    // need to use doAs so that http can find the kerberos tgt
    // NOTE: token renewers should be responsible for the correct UGI!
    try {
        // 更新delegation token 并得到下次超时时间
        dttr.expirationDate =
            UserGroupInformation.getLoginUser().doAs(
                new PrivilegedExceptionAction<Long>() {
                    @Override
                    public Long run() throws Exception {
                        return dttr.token.renew(dttr.conf);
                    }
                });
    } catch (InterruptedException e) {
        throw new IOException(e);
    }
    LOG.info("Renewed delegation-token= [" + dttr + "]");
}

protected void setTimerForTokenRenewal(DelegationTokenToRenew token)
    throws IOException {
    // calculate timer time
    long expiresIn = token.expirationDate - System.currentTimeMillis();
    if (expiresIn <= 0) {
        LOG.info("Will not renew token " + token);
        return;
    }
    long renewIn = token.expirationDate - expiresIn / 10; // little bit before the expiration
    // need to create new task every time
    RenewalTimerTask tTask = new RenewalTimerTask(token);
    token.setTimerTask(tTask); // keep reference to the timer

    renewalTimer.schedule(token.timerTask, new Date(renewIn));
    LOG.info(
        "Renew " + token + " in " + expiresIn + " ms, appId = " +
        token.referringAppIds);
}

再来看更新token的请求与处理细节：

代码语言：javascript
复制
// 客户端发送更新请求
public long renew(Token<?> token, Configuration conf) throws IOException {
    Token<DelegationTokenIdentifier> delToken = (Token<DelegationTokenIdentifier>) token;
    ClientProtocol nn = getNNProxy(delToken, conf);
    try {
        return nn.renewDelegationToken(delToken);
    } catch (RemoteException re) {
        throw re.unwrapRemoteException(InvalidToken.class,
                AccessControlException.class);
    }
}

// 服务端的响应处理
long renewDelegationToken(Token<DelegationTokenIdentifier> token)
    throws InvalidToken, IOException {
    try {
        ...
        expiryTime = dtSecretManager.renewToken(token, renewer);
    } catch (AccessControlException ace) {
        ...
    }
    return expiryTime;
}

public synchronized long renewToken(
    Token<TokenIdent> token,
    String renewer) 
    throws InvalidToken, IOException {
    ByteArrayInputStream buf = new ByteArrayInputStream(token.getIdentifier());
    DataInputStream in = new DataInputStream(buf);
    TokenIdent id = createIdentifier();
    id.readFields(in);
    LOG.info(
        "Token renewal for identifier: " + formatTokenId(id) +
        "; total currentTokens " + currentTokens.size());

    long now = Time.now();
    if (id.getMaxDate() < now) {
        throw new InvalidToken(
            renewer + " tried to renew an expired token " +
            formatTokenId(id) + " max expiration date: " +
            Time.formatTime(id.getMaxDate()) +
            " currentTime: " + Time.formatTime(now));
    }
    if ((id.getRenewer() == null) || (id.getRenewer().toString().isEmpty())) {
        throw new AccessControlException(
            renewer +
            " tried to renew a token " + formatTokenId(id) +
            " without a renewer");
    }
    if (!id.getRenewer().toString().equals(renewer)) {
        throw new AccessControlException(
            renewer +
            " tries to renew a token " + formatTokenId(id) +
            " with non-matching renewer " + id.getRenewer());
    }
    DelegationKey key = getDelegationKey(id.getMasterKeyId());
    if (key == null) {
        throw new InvalidToken(
            "Unable to find master key for keyId=" +
            id.getMasterKeyId() +
            " from cache. Failed to renew an unexpired token " +
            formatTokenId(id) + " with sequenceNumber=" +
            id.getSequenceNumber());
    }
    byte[] password = createPassword(token.getIdentifier(), key.getKey());
    if (!MessageDigest.isEqual(password, token.getPassword())) {
        throw new AccessControlException(
            renewer +
            " is trying to renew a token " +
            formatTokenId(id) + " with wrong password");
    }
    long renewTime = Math.min(id.getMaxDate(), now + tokenRenewInterval);
    String trackingId = getTrackingIdIfEnabled(id);
    DelegationTokenInformation info = 
        new DelegationTokenInformation(renewTime, password, trackingId);

    if (getTokenInfo(id) == null) {
        throw new InvalidToken(
            "Renewal request for unknown token " + formatTokenId(id));
    }
    updateToken(id, info);
    return renewTime;
}

3）token达到最大生命周期的处理

在定时器中，会捕获更新抛出的异常，并直接移除失效的token。

但是注意：在每次更新之前，会按需重新申请新的delegation token（后面再展开讲解）

代码语言：javascript
复制
public void run() {
    if (cancelled.get()) {
        return;
    }

    Token<?> token = dttr.token;

    try {
        // 先判断是否需要申请新的token
        requestNewHdfsDelegationTokenIfNeeded(dttr);
        // if the token is not replaced by a new token, renew the token
        if (!dttr.isTimerCancelled()) {
            renewToken(dttr);
            setTimerForTokenRenewal(dttr);// set the next one
        } else {
            LOG.info("The token was removed already. Token = [" + dttr + "]");
        }
    } catch (Exception e) {
        LOG.error("Exception renewing token" + token + ". Not rescheduled", e);
        removeFailedDelegationToken(dttr);
    }
}

【问题分析】

来看看前面问题失败的相关日志，复盘分析下。

首先从NM的日志中发现任务在重试时，因为无法下载资源（到本地）导致无法启动任务，而下载资源失败的原因则是因为无效的token。

代码语言：javascript
复制
2022-07-18 13:44:18,665 WARN org.apache.hadoop.ipc.Client: Exception encountered while connecting to the server : org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.token.SecretManager$InvalidToken): token (HDFS_DELEGATION_TOKEN token 4361 for hncscwc) can't be found in cache
2022-07-18 13:44:18,669 WARN org.apache.hadoop.yarn.server.nodemanager.containermanager.localizer.ResourceLocalizationService: { hdfs://hdfsHACluster/user/hncscwc/.flink/application_1637733238080_3800/application_1637733238080_38002636034628721129021.tmp, 1656925873322, FILE, null } failed: token (HDFS_DELEGATION_TOKEN token 4361 for hncscwc) can't be found in cache
org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.token.SecretManager$InvalidToken): token (HDFS_DELEGATION_TOKEN token 4361 for hncscwc) can't be found in cache
  at org.apache.hadoop.ipc.Client.getRpcResponse(Client.java:1486)
  at org.apache.hadoop.ipc.Client.call(Client.java:1432)
  at org.apache.hadoop.ipc.Client.call(Client.java:1342)
  at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:227)
  at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:116)
  at com.sun.proxy.$Proxy15.getFileInfo(Unknown Source)
  at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:796)
  at sun.reflect.GeneratedMethodAccessor172.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:411)
  at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeMethod(RetryInvocationHandler.java:165)
  at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invoke(RetryInvocationHandler.java:157)
  at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeOnce(RetryInvocationHandler.java:95)
  at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:348)
  at com.sun.proxy.$Proxy16.getFileInfo(Unknown Source)
  at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1649)
  at org.apache.hadoop.hdfs.DistributedFileSystem$27.doCall(DistributedFileSystem.java:1440)
  at org.apache.hadoop.hdfs.DistributedFileSystem$27.doCall(DistributedFileSystem.java:1437)
  at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
  at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1452)
  at org.apache.hadoop.yarn.util.FSDownload.copy(FSDownload.java:253)
  at org.apache.hadoop.yarn.util.FSDownload.access$000(FSDownload.java:63)
  at org.apache.hadoop.yarn.util.FSDownload$2.run(FSDownload.java:361)
  at org.apache.hadoop.yarn.util.FSDownload$2.run(FSDownload.java:359)
  at java.security.AccessController.doPrivileged(Native Method)
  at javax.security.auth.Subject.doAs(Subject.java:422)
  at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1922)
  at org.apache.hadoop.yarn.util.FSDownload.call(FSDownload.java:359)
  at org.apache.hadoop.yarn.util.FSDownload.call(FSDownload.java:62)
  at java.util.concurrent.FutureTask.run(FutureTask.java:266)
  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
  at java.util.concurrent.FutureTask.run(FutureTask.java:266)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
  at java.lang.Thread.run(Thread.java:748)

为什么会出现无效的token，接着再看RM的日志。

代码语言：javascript
复制
2022-07-04 17:11:13,400 INFO org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler: Application 'application_1637733238080_3800' is submitted without priority hence considering default queue/cluster priority: 0
2022-07-04 17:11:13,424 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657012273422; apps=[application_1637733238080_3800]]
2022-07-05 14:47:13,462 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657090033446; apps=[application_1637733238080_3800]]
2022-07-06 12:23:13,467 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657167793465; apps=[application_1637733238080_3800]]
2022-07-07 09:59:13,487 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657245553484; apps=[application_1637733238080_3800]]
2022-07-08 07:35:13,532 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657323313511; apps=[application_1637733238080_3800]]
2022-07-09 05:11:13,551 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657401073532; apps=[application_1637733238080_3800]]
2022-07-10 02:47:13,564 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657478833547; apps=[application_1637733238080_3800]]
2022-07-11 00:23:13,591 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800]]
2022-07-11 17:11:07,361 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800]]
2022-07-11 17:11:07,361 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renew Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800] in 6032 ms, appId = [application_1637733238080_3800]
2022-07-11 17:11:12,793 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800]]
2022-07-11 17:11:12,793 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renew Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800] in 600 ms, appId = [application_1637733238080_3800]
2022-07-11 17:11:13,337 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800]]
2022-07-11 17:11:13,337 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renew Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800] in 56 ms, appId = [application_1637733238080_3800]
2022-07-11 17:11:13,391 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renewed delegation-token= [Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800]]
2022-07-11 17:11:13,391 INFO org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Renew Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc);exp=1657530673393; apps=[application_1637733238080_3800] in 2 ms, appId = [application_1637733238080_3800]
2022-07-11 17:11:13,398 ERROR org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: Exception renewing tokenKind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:hdfsHACluster, Ident: (HDFS_DELEGATION_TOKEN token 4361 for hncscwc). Not rescheduled
org.apache.hadoop.security.token.SecretManager$InvalidToken: hadoop tried to renew an expired token (HDFS_DELEGATION_TOKEN token 4361 for hncscwc) max expiration date: 2022-07-11 17:11:13,393+0800 currentTime: 2022-07-11 17:11:13,394+0800
  at org.apache.hadoop.security.token.delegation.AbstractDelegationTokenSecretManager.renewToken(AbstractDelegationTokenSecretManager.java:499)
  at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.renewDelegationToken(FSNamesystem.java:5952)
  at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.renewDelegationToken(NameNodeRpcServer.java:675)
  at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.renewDelegationToken(ClientNamenodeProtocolServerSideTranslatorPB.java:1035)
  at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
  at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:447)
  at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:989)
  at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:850)
  at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:793)
  at java.security.AccessController.doPrivileged(Native Method)
  at javax.security.auth.Subject.doAs(Subject.java:422)
  at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1922)
  at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2489)

  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
  at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
  at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
  at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteException.java:121)
  at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteException.java:88)
  at org.apache.hadoop.hdfs.DFSClient$Renewer.renew(DFSClient.java:761)
  at org.apache.hadoop.security.token.Token.renew(Token.java:458)
  at org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer$1.run(DelegationTokenRenewer.java:601)
  at org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer$1.run(DelegationTokenRenewer.java:598)
  at java.security.AccessController.doPrivileged(Native Method)
  at javax.security.auth.Subject.doAs(Subject.java:422)
  at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1922)
  at org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer.renewToken(DelegationTokenRenewer.java:597)
  at org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer$RenewalTimerTask.run(DelegationTokenRenewer.java:531)
  at java.util.TimerThread.mainLoop(Timer.java:555)
  at java.util.TimerThread.run(Timer.java:505)
Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.token.SecretManager$InvalidToken): hadoop tried to renew an expired token (HDFS_DELEGATION_TOKEN token 4361 for hncscwc) max expiration date: 2022-07-11 17:11:13,393+0800 currentTime: 2022-07-11 17:11:13,394+0800
  at org.apache.hadoop.security.token.delegation.AbstractDelegationTokenSecretManager.renewToken(AbstractDelegationTokenSecretManager.java:499)
  at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.renewDelegationToken(FSNamesystem.java:5952)
  at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.renewDelegationToken(NameNodeRpcServer.java:675)
  at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.renewDelegationToken(ClientNamenodeProtocolServerSideTranslatorPB.java:1035)
  at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
  at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:447)
  at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:989)
  at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:850)
  at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:793)
  at java.security.AccessController.doPrivileged(Native Method)
  at javax.security.auth.Subject.doAs(Subject.java:422)
  at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1922)
  at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2489)

  at org.apache.hadoop.ipc.Client.getRpcResponse(Client.java:1486)
  at org.apache.hadoop.ipc.Client.call(Client.java:1432)
  at org.apache.hadoop.ipc.Client.call(Client.java:1342)
  at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:227)
  at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:116)
  at com.sun.proxy.$Proxy94.renewDelegationToken(Unknown Source)
  at 
org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.renewDelegationToken(ClientNamenodeProtocolTranslatorPB.java:964)
  at sun.reflect.GeneratedMethodAccessor277.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:411)
  at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeMethod(RetryInvocationHandler.java:165)
  at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invoke(RetryInvocationHandler.java:157)
  at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeOnce(RetryInvocationHandler.java:95)
  at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:348)
  at com.sun.proxy.$Proxy95.renewDelegationToken(Unknown Source)
  at org.apache.hadoop.hdfs.DFSClient$Renewer.renew(DFSClient.java:759)
  ... 10 more
2022-07-11 17:11:13,399 ERROR org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRenewer: removing failed delegation token for appid=[application_1637733238080_3800];t=ha-hdfs:hdfsHACluster

从上面的日志可以看到，任务从提交后，delegation token每天都有在更新，然而运行到第7天后，更新失败而失效。失效后，NN内部会删除无效的token，此时如果任务失败需要重试，或者任务结束需要进行日志聚合，都会继续使用该无效的token来操作hdfs，最终结果就是在NN中找不到对应的token而抛异常导致失败。

【问题解决】

要解决该问题，一种最简单直接的办法就是加大delegation token的最大生命周期时间。

但一开始觉得该办法略有些low，尤其对于flink长周期运行的实时任务的场景，是无法确定任务的运行时长的，因此也就无法确定设置token的最大生命周期。

因此，再次分析了源码，发现RM中对于将要过期（超过最大生命周期）的delegation token，会按需重新申请一个新的token，也就是定时器线程中token更新之前的requestNewHdfsDelegationTokenIfNeeded方法。

来看看具体的实现逻辑：

代码语言：javascript
复制
private void requestNewHdfsDelegationTokenIfNeeded(
    final DelegationTokenToRenew dttr) 
    throws IOException, InterruptedException {

    // 拥有特权 并且 token类型为委派token 并且 快到最大生命周期
    if (hasProxyUserPrivileges &&
        dttr.maxDate - dttr.expirationDate < credentialsValidTimeRemaining &&
        dttr.token.getKind().equals(HDFS_DELEGATION_KIND)) {

        final Collection<ApplicationId> applicationIds;
        synchronized (dttr.referringAppIds) {
            applicationIds = new HashSet<>(dttr.referringAppIds);
            dttr.referringAppIds.clear();
        }
        // remove all old expiring hdfs tokens for this application.
        for (ApplicationId appId : applicationIds) {
            Set<DelegationTokenToRenew> tokenSet = appTokens.get(appId);
            if (tokenSet == null || tokenSet.isEmpty()) {
                continue;
            }
            Iterator<DelegationTokenToRenew> iter = tokenSet.iterator();
            synchronized (tokenSet) {
                while (iter.hasNext()) {
                    DelegationTokenToRenew t = iter.next();
                    if (t.token.getKind().equals(HDFS_DELEGATION_KIND)) {
                        iter.remove();
                        allTokens.remove(t.token);
                        t.cancelTimer();
                        LOG.info("Removed expiring token " + t);
                    }
                }
            }
        }
        LOG.info("Token= (" + dttr + ") is expiring, request new token.");
        requestNewHdfsDelegationTokenAsProxyUser(
            applicationIds, dttr.user,
            dttr.shouldCancelAtEnd);
    }
}

申请到新的token之后，会在RM内部进行更新，然后通过NM的心跳响应同步给NM。

代码语言：javascript
复制
private void requestNewHdfsDelegationTokenAsProxyUser(
    ...
    // Get new hdfs tokens for this user
    Credentials credentials = new Credentials();
    Token<?>[] newTokens = obtainSystemTokensForUser(user, credentials);
    DataOutputBuffer dob = new DataOutputBuffer();
    credentials.writeTokenStorageToStream(dob);
    ByteBuffer byteBuffer = ByteBuffer.wrap(dob.getData(), 0, dob.getLength());
    for (ApplicationId applicationId : referringAppIds) {
        // 更新app的delegation token
        // 在NM心跳时进行同步
        rmContext.getSystemCredentialsForApps().put(applicationId, byteBuffer);
    }
} 

public NodeHeartbeatResponse nodeHeartbeat(NodeHeartbeatRequest request)
    throws YarnException, IOException {
    ...
    ConcurrentMap<ApplicationId, ByteBuffer> systemCredentials =
        rmContext.getSystemCredentialsForApps();
    if (!systemCredentials.isEmpty()) {
        nodeHeartBeatResponse.setSystemCredentialsForApps(systemCredentials);
    }
    ...
}

NM在心跳响应中解析出token并在内存中更新保存，后续任务重试启动资源本地化和任务结束触发日志聚合时会使用到。

注意：这里只提到了资源本地化和日志聚合时会使用到更新后的token，那么正在运行的任务会用到更新后的token吗？

答案是不会（至少是2.X版本不会）。主要是因为：token已经写入到持久化文件中，任务启动时读取该文件获取token并使用；delegation token在更新后没有写入到持久化文件中，即使可以写入（更新）到该文件，也需要有机制通知任务进程更新读取该文件才行。因此正在运行中的任务在token过期后继续操作hdfs仍旧会抛出异常。

另外，在3.X的最新版本中，注意到有相关代码的改动，应该是通知正在运行的container，但具体细节还未深入研究，后面有时间再调研。

【相关配置】

与delegation token相关的配置包括：

配置项名称

默认值

说明

dfs.namenode.delegation.key.update-interval

1天

token更新密钥的时间间隔

dfs.namenode.delegation.token.renew-interval

1天

token更新的时间间隔

dfs.namenode.delegation.token.max-lifetime

7天

token的最大生命周期

yarn.resourcemanager.delegation-token.alwys-cancel

false

RM结束时是否需要移除token

yarn.resourcemanager.proxy-user-privileges.enabled

false

是否开启特权在delegation token快过期时重新申请新的token

yarn.resourcemanager.system-credentials.valid-time-remaining

10800000

距离最大生命周期之前多长时间进行重新申请token的操作，单位毫秒

yarn.resourcemanager.delegation-token-renewer.thread-count

50

RM中delegation token更新线程的线程数

【总结】

本文通过一个实际的问题，并结合源码讲解了hadoop的delegation token的相关原理。

文中如有不对的地方，欢迎拍砖指正。

本文参与 腾讯云自媒体同步曝光计划，分享自微信公众号。
原始发表：2022-07-25，如有侵权请联系 cloudcommunity@tencent.com 删除
yarn
node.js
flink
大数据

本文分享自 陈猿解码 微信公众号，前往查看

如有侵权，请联系 cloudcommunity@tencent.com 删除。

本文参与 腾讯云自媒体同步曝光计划  ，欢迎热爱写作的你一起参与！

yarn
node.js
flink
大数据
评论
登录后参与评论
0 条评论
热度
最新
登录 后参与评论
推荐阅读
LV.
文章
0
获赞
0
相关产品与服务
大数据
全栈大数据产品，面向海量数据场景，帮助您 “智理无数，心中有数”！
产品介绍
11.11 上云拼团GO
领券

腾讯云开发者

扫码关注腾讯云开发者

扫码关注腾讯云开发者

领取腾讯云代金券

热门产品

热门推荐

更多推荐

Copyright © 2013 - 2024 Tencent Cloud. All Rights Reserved. 腾讯云 版权所有 

深圳市腾讯计算机系统有限公司 ICP备案/许可证号：粤B2-20090059 深公网安备号 44030502008569

腾讯云计算（北京）有限责任公司 京ICP证150476号 |  京ICP备11018762号 | 京公网安备号11010802020287

问题归档专栏文章快讯文章归档关键词归档开发者手册归档开发者手册 Section 归档

Copyright © 2013 - 2024 Tencent Cloud.

All Rights Reserved. 腾讯云 版权所有

登录 后参与评论
3