为CDH 5集群添加Kerberos支持

太过爱你忘了你带给我的痛 2022-08-22 11:23 218阅读 0赞

[GitHub][]      Kerberos

--------------------

参考链接：   
\+ [Configuring Authentication in Clouera Manager][]   
\+ [Understanding Kerberos][]   
\+ [Instlling Kerberos][]   
\+ [Troubleshooting Authentication Issues][]   
\+ [Configuring YARN for Long-running Applications][]

# 前提 #

Hadoop的集群上已安装好了CDH 5.3.2 以及 Cloudera Manager 5.3.2。   
Kerberos v5 在Hadoop集群上也已经安装好了，并且Kerberos中存在一个名为『GUIZHOU.COM』的realm，里面包含 hadoop1.com - hadoop5.com 共5台主机，hadoop1.com上运行cloudera manager server，5台主机都运行着cloudera manager agent。

我们再看一下我们KDC的配置。

*  hadopo\[1-5\].com主机上 */etc/krb5.conf* 文件的内容

[logging]
       default = FILE:/var/log/krb5libs.log
       kdc = FILE:/var/log/krb5kdc.log
       admin_server = FILE:/var/log/kadmind.log
       
       [libdefaults]
       default_realm = GUIZHOU.COM
       dns_lookup_realm = false
       dns_lookup_kdc = false
       ticket_lifetime = 24h
       renew_lifetime = 7d
       forwardable = true
       renewable = true
       
       [realms]
       GUIZHOU.COM = { 
       kdc = hadoop1.com
       admin_server = hadoop1.com
       }
       
       [domain_realm]
       hadoop1.com = GUIZHOU.COM
       hadoop2.com = GUIZHOU.COM
       hadoop3.com = GUIZHOU.COM
       hadoop4.com = GUIZHOU.COM
       hadoop5.com = GUIZHOU.COM

*  hadoop1.com主机上 */var/kerberos/krb5kdc/kdc.conf* 文件的内容

[kdcdefaults]
       kdc_ports = 88
       kdc_tcp_ports = 88
       [realms]
       GUIZHOU.COM = { 
       #master_key_type = aes256-cts
       acl_file = /var/kerberos/krb5kdc/kadm5.acl
       dict_file = /usr/share/dict/words
       admin_keytab = /var/kerberos/krb5kdc/kadm5.keytab
       supported_enctypes = aes256-cts:normal aes128-cts:normal des3-hmac-sha1:normal arcfour-hmac:normal des-hmac-sha1:normal des-cbc-md5:normal des-cbc-crc:normal
       max_life = 1d
       max_renewable_life = 7d
       }

# 配置过程 #

## 安装JCE Policy File ##

如果你的操作系统是CentOS/Red Hat 5.5或更高版本（这些OS默认使用AES-256来加密tickets），则你就必须在所有的集群节点以及Hadoop使用者的主机上安装 [Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy File][Java Cryptography Extension _JCE_ Unlimited Strength Jurisdiction Policy File] 。

为Cloudera Hadoop集群安装JCE Policy File的过程可以 [参考这里][Link 1] 。

## 创建Cloudera Manager Principal ##

为了能在集群中创建和部署host principals和keytabs，Cloudera Manager Server必须有一个Kerberos principal来创建其他的账户。如果一个principal的名字的第二部分是`admin`（例如， *username/admin@YOUR-LOCAL-REALM.COM* ），那么该principal就拥有administrative privileges。

在KDC server主机上，创建一个名为『cloudera-scm』的principal，并将其密码设为『cloudera-scm-1234』。执行命令：

[root@hadoop1 ~]# kadmin.local 
       Authenticating as principal root/admin@GUIZHOU.COM with password.
       kadmin.local: addprinc -pw cloudera-scm-1234 cloudera-scm/admin@GUIZHOU.COM
       WARNING: no policy specified for cloudera-scm/admin@GUIZHOU.COM; defaulting to no policy
       Principal "cloudera-scm/admin@GUIZHOU.COM" created.

通过执行`kadmin.local`中的`listprincs`命令可以看到创建了一个名为『cloudera-scm/admin@GUIZHOU.COM』的principal：

kadmin.local: listprincs
       K/M@GUIZHOU.COM
       admin/admin@GUIZHOU.COM
       cloudera-scm/admin@GUIZHOU.COM
       kadmin/admin@GUIZHOU.COM
       kadmin/changepw@GUIZHOU.COM
       kadmin/hadoop1.com@GUIZHOU.COM
       krbtgt/GUIZHOU.COM@GUIZHOU.COM
       xiaotao@GUIZHOU.COM

## 通过CDH Wizard来启用Kerberos ##

在Cloudera Manager界面上点击Cluster名称右边的『Enable Kerberos』选项。点击之后，会要求你确认以下的事项：

> 1.  KDC已经安装好并且正在运行；   
>       
>     
> 2.  将KDC配置为允许renewable tickets with non-zerolifetime;   
>     方法：在kdc.conf文件中如下配置   
>     
>     
>         [kdcdefaults]
>               kdc_ports = 88
>               kdc_tcp_ports = 88
>               
>               [realms]
>               GUIZHOU.COM = { 
>               acl_file = /var/kerberos/krb5kdc/kadm5.acl
>               dict_file = /usr/share/dict/words
>               admin_keytab = /var/kerberos/krb5kdc/kadm5.keytab
>               supported_enctypes = aes256-cts:normal aes128-cts:normal des3-hmac-sha1:normal arcfour-hmac:normal des-hmac-sha1:normal des-cbc-md5:normal des-cbc-crc:normal
>               max_life = 1d
>               max_renewable_life = 7d
>               }
> 
> 其中必要的选项是`kdc_tcp_ports`、`max_life`和`max_renewable_life`。   
>   
>   
> 3. 在Cloudera Manager Server上安装`openldap-clients`   
>   
>   
> 4. 为Cloudera Manager创建一个principal，使其能够有权限在KDC中创建其他的principals，这一步在上一节中已经完成了。

点击continue，进入[下一页][Link 2]进行配置，要注意的是：这里的『Kerberos Encryption Types』必须跟KDC实际支持的加密类型匹配（即kdc.conf中的值）。

点击continue，进入下一页，这一页中可以不勾选『Manage krb5.conf through Cloudera Manager』。

点击continue，进入下一页，输入Cloudera Manager Principal（就我们之前创建的*cloudera-scm/admin@GUIZHOU.COM* ）的username和password。

点击continue，进入下一页，导入KDC Account Manager Credentials。

点击continue，进入下一页，restart cluster并且enable Kerberos。

大功告成！现在，Cloudera Manager Server/Hosts可以重启，但是CDH cluster还不能启动。

## 创建HDFS超级用户 ##

当我们为HDFS服务开启Kerberos之后，就无法直接通过`sudo -u hdfs`来访问HDFS了，因为此时还不存在一个名为`hdfs`的principal，无法通过Kerberos的authenticatin。因此必须首先创建一个Kerberos principal（其第一部分是*hdfs*）。

[root@hadoop1 ~]# kadmin.local 
       Authenticating as principal root/admin@GUIZHOU.COM with password.
       kadmin.local: addprinc hdfs@GUIZHOU.COM
       WARNING: no policy specified for hdfs@GUIZHOU.COM; defaulting to no policy
       Enter password for principal "hdfs@GUIZHOU.COM": 
       Re-enter password for principal "hdfs@GUIZHOU.COM": 
       Principal "hdfs@GUIZHOU.COM" created.

这里我们为principal『hdfs@GUIZHOU.com』设置了密码『hdfs-1234』。

为了能够以hdfs的身份来运行命令，必须为 *hdfs* principal 获取Kerberos credentials。因此，运行命令：

[root@hadoop1 ~]# kinit hdfs@GUIZHOU.COM

## 看看现在KDC database中有哪些principals ##

通过CDH Wizard成功地为Hadoop集群添加了Kerberos支持之后，可以看一下现在KDC database 中存在哪些principals。在KDC主机上运行`kadmin.localo`，在其中用`listprincs`命令来查看。

> \[root@hadoop1 ~\]\# kadmin.local   
> Authenticating as principal hdfs/admin@GUIZHOU.COM with password.   
> kadmin.local: listprincs   
> HTTP/hadoop1.com@GUIZHOU.COM   
> HTTP/hadoop2.com@GUIZHOU.COM   
> HTTP/hadoop3.com@GUIZHOU.COM   
> HTTP/hadoop4.com@GUIZHOU.COM   
> HTTP/hadoop5.com@GUIZHOU.COM   
> K/M@GUIZHOU.COM   
> admin/admin@GUIZHOU.COM   
> cloudera-scm/admin@GUIZHOU.COM   
> hbase/hadoop1.com@GUIZHOU.COM   
> hbase/hadoop2.com@GUIZHOU.COM   
> hbase/hadoop3.com@GUIZHOU.COM   
> hbase/hadoop4.com@GUIZHOU.COM   
> hbase/hadoop5.com@GUIZHOU.COM   
> hdfs/hadoop1.com@GUIZHOU.COM   
> hdfs/hadoop2.com@GUIZHOU.COM   
> hdfs/hadoop3.com@GUIZHOU.COM   
> hdfs/hadoop4.com@GUIZHOU.COM   
> hdfs/hadoop5.com@GUIZHOU.COM   
> hdfs@GUIZHOU.COM   
> hive/hadoop1.com@GUIZHOU.COM   
> hive/hadoop2.com@GUIZHOU.COM   
> hive/hadoop3.com@GUIZHOU.COM   
> hive/hadoop4.com@GUIZHOU.COM   
> hive/hadoop5.com@GUIZHOU.COM   
> httpfs/hadoop2.com@GUIZHOU.COM   
> hue/hadoop1.com@GUIZHOU.COM   
> hue/hadoop2.com@GUIZHOU.COM   
> hue/hadoop3.com@GUIZHOU.COM   
> kadmin/admin@GUIZHOU.COM   
> kadmin/changepw@GUIZHOU.COM   
> kadmin/hadoop1.com@GUIZHOU.COM   
> krbtgt/GUIZHOU.COM@GUIZHOU.COM   
> mapred/hadoop4.com@GUIZHOU.COM   
> oozie/hadoop4.com@GUIZHOU.COM   
> spark/hadoop1.com@GUIZHOU.COM   
> test@GUIZHOU.COM   
> xiaotao@GUIZHOU.COM   
> yarn/hadoop1.com@GUIZHOU.COM   
> yarn/hadoop2.com@GUIZHOU.COM   
> yarn/hadoop3.com@GUIZHOU.COM   
> yarn/hadoop4.com@GUIZHOU.COM   
> yarn/hadoop5.com@GUIZHOU.COM   
> zookeeper/hadoop1.com@GUIZHOU.COM   
> zookeeper/hadoop4.com@GUIZHOU.COM   
> zookeeper/hadoop5.com@GUIZHOU.COM

可以看到，很多的pincipals都是CDH帮我们添加进去的。

## 为每一个User Account创建Kerberos Principal ##

当集群运行Kerberos后，每一个Hadoop user都必须有一个principal或者keytab来获取Kerberos credentials，这样才能访问集群并使用Hadoop的服务。也就是说，如果Hadoop集群存在一个名为`tom@GUIZHOU.COM`的principal，那么在集群的每一个节点上应该存在一个名为`tom`的Linux用户。同时，在HDFS中的目录`/user`要存在相应的用户目录（即`/user/tom`），且该目录的owner和group都要是`tom`。

> Linux user 的 user id 要大于等于1000，否则会无法提交Job。例如，如果以hdfs（id为496）的身份提交一个job，就会看到以下的错误信息：
> 
> > INFO mapreduce.Job: Job job\_1442654915965\_0002 failed with state FAILED due to: Application application\_1442654915965\_0002 failed 2 times due to AM Container for appattempt\_1442654915965\_0002\_000002 exited with exitCode: -1000 due to: Application application\_1442654915965\_0002 initialization failed (exitCode=255) with output: Requested user hdfs is not whitelisted and has id 496,which is below the minimum allowed 1000   
> > 
> 
>   
>   
> 解决方法：   
> 1. 修改一个用户的user id?   
>     用命令 `usermod -u <new-user-id> <user>`   
> 2. 修改Clouder关于这个该项的设置   
>     在 Cloudera中修改配置项   
>     `YARN -> Node Manager Group -> Security -> Minimum User ID`   
>     可见该配置项的默认值是1000，把它改为0即可。

## 确认Kerberized Hadoop Cluster可以正常使用 ##

1.  确认HDFS可以正常使用
    
    登录到某一个节点后，切换到`hdfs`用户，然后用`kinit`来获取credentials。   
    现在用'hadoop dfs -ls /'应该能正常输出结果。
    
    用`kdestroy`销毁credentials后，再使用`hadoop dfs -ls /`会发现报错。
    
      
    
2.  确认可以正常提交MapReduce job
    
    获取了hdfs的证书后，提交一个PI程序，如果能正常提交并成功运行，则说明Kerberized Hadoop cluster在正常工作。
    
    如果能提交Job，但是运行时出错，如下：
    
    > \[hdfs@hadoop2 ~\]$ hadoop jar /opt/cloudera/parcels/CDH-5.3.2-1.cdh5.3.2.p0.10/jars/hadoop-examples.jar pi 4 4   
    > Number of Maps = 4   
    > Samples per Map = 4   
    > Wrote input for Map \#0   
    > Wrote input for Map \#1   
    > Wrote input for Map \#2   
    > Wrote input for Map \#3   
    > Starting Job   
    > 15/09/19 17:30:40 INFO client.RMProxy: Connecting to ResourceManager at hadoop5.com/59.215.222.76:8032   
    > 15/09/19 17:30:40 INFO hdfs.DFSClient: Created HDFS\_DELEGATION\_TOKEN token 1 for hdfs on 59.215.222.76:8020   
    > 15/09/19 17:30:40 ERROR hdfs.KeyProviderCache: Could not find uri with key \[dfs.encryption.key.provider.uri\] to create a keyProvider !!   
    > 15/09/19 17:30:40 INFO security.TokenCache: Got dt for hdfs://hadoop5.com:8020; Kind: HDFS\_DELEGATION\_TOKEN, Service: 59.215.222.76:8020, Ident: (HDFS\_DELEGATION\_TOKEN token 1 for hdfs)   
    > 15/09/19 17:30:40 ERROR hdfs.KeyProviderCache: Could not find uri with key \[dfs.encryption.key.provider.uri\] to create a keyProvider !!   
    > 15/09/19 17:30:40 ERROR hdfs.KeyProviderCache: Could not find uri with key \[dfs.encryption.key.provider.uri\] to create a keyProvider !!   
    > 15/09/19 17:30:40 ERROR hdfs.KeyProviderCache: Could not find uri with key \[dfs.encryption.key.provider.uri\] to create a keyProvider !!
    
    实际上这是一个bug，可以忽略它，不影响Job的运行。

## 确保其他组件（ZooKeeper / HBase等）正常运行 ##

现在虽然HDFS可以正常运行，YARN job也可以正常运行，但是如果启动HBase，那么会发现HBase不能正常启动。

所以，在安装了Kerberized CDH 后，我们还要针对HBase（以及ZooKeeper）进行配置，具体步骤参考 [HBase Authentication][]

# 常见问题 #

参考 [Troubleshooting Authentication Issues][]

## 1. 运行任何hadoop命令都会失败 ##

例如，以 *hdfs* 的身份运行`hadoop dfs -ls /`，出现以下异常：

> \[hdfs@hadoop2 ~\]$ hadoop dfs -ls /   
> DEPRECATED: Use of this script to execute hdfs command is deprecated.   
> Instead use the hdfs command for it.
> 
>   
> 15/09/19 14:24:38 WARN security.UserGroupInformation: PriviledgedActionException as:hdfs (auth:KERBEROS) cause:javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]   
>   
> 15/09/19 14:24:38 WARN ipc.Client: Exception encountered while connecting to the server : javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]   
>   
> 15/09/19 14:24:38 WARN security.UserGroupInformation: PriviledgedActionException as:hdfs (auth:KERBEROS) cause:java.io.IOException: javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]
> 
> ls: Failed on local exception: java.io.IOException: javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]; Host Details : local host is: "hadoop2.com/59.215.222.72"; destination host is: "hadoop5.com":8020;

如果出现这种情况，逐项检查：

> 1.  检查操作时的身份，例如是否是用hdfs身份操作的；
> 2.  检查是否已经获得了credentials：`kinit hdfs@GUIZHOU.COM`;
> 3.  尝试删除credentials并重新获取：`destroy` => `kinit`
> 4.  tickets是否是renewable，检查 *kdc.conf* 的配置；
> 5.  检查是否安装了JCE Policy File，这可以通过Cloudera的Kerberos Inspector来检查；

## 2. hdfs用户无法提交一个Job ##

1.  『user id』的值不够大
    
    Linux user 的 user id要大于等于1000，否则会无法提交Job。例如，如果以hdfs（id为496）的身份提交一个job，就会看到以下的错误信息：
    
    > INFO mapreduce.Job: Job job\_1442654915965\_0002 failed with state FAILED due to: Application application\_1442654915965\_0002 failed 2 times due to AM Container for appattempt\_1442654915965\_0002\_000002 exited with exitCode: -1000 due to: Application application\_1442654915965\_0002 initialization failed (exitCode=255) with output: Requested user hdfs is not whitelisted and has id 496,which is below the minimum allowed 1000   
    > 
    
    解决方法：   
    a). 修改一个用户的user id?   
        用命令 `usermod -u <new-user-id> <user>`   
        不推荐采取这种解决方式，否则`hdfs`用户的非家目录中的文件的owner都要手动去一一修改。   
    b). 修改Clouder关于这个该项的设置   
        在 Cloudera中修改配置项   
        `YARN -> Node Manager Group -> Security -> Minimum User ID`   
        可见该配置项的默认值是1000，把它改为一个较小的值即可。
    
      
    
2.  hdfs用户被禁止运行 YARN container
    
    配置了Kerberos之后，有几个用户被禁止运行YARN runner，默认的被禁用户包括『hdfs, yarn, mapred, bin』，如果用hdfs提交一个YARN job，则会遇到以下的异常：
    
    > 15/09/20 12:18:25 INFO mapreduce.Job: Job job\_1442722429197\_0001 failed with state FAILED due to: Application application\_1442722429197\_0001 failed 2 times due to AM Container for appattempt\_1442722429197\_0001\_000002 exited with exitCode: -1000 due to: Application application\_1442722429197\_0001 initialization failed (exitCode=255) with output: Requested user hdfs is banned
    
    解决方法，将hdfs用户从banned.users名单中去掉，参考 [这里][Link 3]。

## 3. YARN job运行时无法创建缓存目录 ##

> \[hdfs@hadoop2 ~\]$ hadoop jar /opt/cloudera/parcels/CDH-5.3.2-1.cdh5.3.2.p0.10/jars/hadoop-examples.jar pi 2 5   
> Number of Maps = 2   
> Samples per Map = 5   
> Wrote input for Map \#0   
> Wrote input for Map \#1   
> Starting Job   
> 15/09/20 13:08:36 INFO mapreduce.Job: map 0% reduce 0%   
> 15/09/20 13:08:36 INFO mapreduce.Job: Job job\_1442724165689\_0005 failed with state FAILED due to: Application application\_1442724165689\_0005 failed 2 times due to AM Container for appattempt\_1442724165689\_0005\_000002 exited with exitCode: -1000 due to: Application application\_1442724165689\_0005 initialization failed (exitCode=255) with output: main : command provided 0   
> main : user is hdfs   
> main : requested yarn user is hdfs   
> Can't create directory /data/data/yarn/nm/usercache/hdfs/appcache/application\_1442724165689\_0005 - Permission denied   
> Did not create any app directories   
> . Failing this attempt.. Failing the application.   
> 15/09/20 13:08:36 INFO mapreduce.Job: Counters: 0   
> Job Finished in 15.144 seconds   
> java.io.FileNotFoundException: File does not exist: hdfs://hadoop5.com:8020/user/hdfs/QuasiMonteCarlo\_1442725699335\_673190642/out/reduce-out

解决方法：   
在每一个NodeManager节点上删除该用户的缓存目录，对于用户`hdfs`，是`/data/data/yarn/nm/usercache/hdfs`。

原因：   
该缓存目录在集群进入Kerberos状态前就已经存在了。例如当我们还没为集群Kerberos支持的时候，就用该用户跑过YARN应用。也许这是一个[bug][]

## 4. 个别节点无法通过Kerberos验证 ##

在为CDH配置好了Kerberos后，在某些节点上，可以通过`kinit hdfs`来获取`hdfs@GUIZHOU`这个credentials，然后可以操作HDFS文件系统。但是在某些节点上，即使在获取了`hdfs`的ticket之后，也无法操作HDFS文件系统，如下：

> \[hdfs@hadoop1 ~\]$ kinit hdfs   
> Password for hdfs@GUIZHOU.COM:   <这里输入密码 hdfs-1234>
> 
> \[hdfs@hadoop1 ~\]$ klist        该principal已经获得了ticket   
> Ticket cache: FILE:/tmp/krb5cc\_1100   
> Default principal: hdfs@GUIZHOU.COM
> 
> Valid starting             Expires                     Service principal   
> 09/21/15 10:10:21    09/22/15 10:10:21    krbtgt/GUIZHOU.COM@GUIZHOU.COM   
>                renew until 09/21/15 10:10:21
> 
> \[hdfs@hadoop1 ~\]$ hadoop dfs -ls /   
> DEPRECATED: Use of this script to execute hdfs command is deprecated.   
> Instead use the hdfs command for it.     该principal还是无法操作HDFS
> 
> 15/09/21 10:10:36 WARN security.UserGroupInformation: PriviledgedActionException as:hdfs (auth:KERBEROS) cause:javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]
> 
> 15/09/21 10:10:36 WARN ipc.Client: Exception encountered while connecting to the server : javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]
> 
> 15/09/21 10:10:36 WARN security.UserGroupInformation: PriviledgedActionException as:hdfs (auth:KERBEROS) cause:java.io.IOException: javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]
> 
> ls: Failed on local exception: java.io.IOException: javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]; Host Details : local host is: "hadoop1.com/59.215.222.3"; destination host is: "hadoop5.com":8020;

在集群的每一个节点上尝试，发现只有hadoop1.com这个节点上存在这个问题，其他4个节点（hadoop2.com - hadoop5.com）上都没有这个问题。所以，应该是这个节点的某些配置有问题。

检查集群每个节点的Kerberos配置   
Cloudera Manager => Administration => Kerberos => Security Inspector => (等待检测结果···) => Show Inspector Results，可以发现hadoop1.com节点上的JCE文件没有安装好，见 [截图][Link 4]。

所以，下面我们就要为该节点安装JCE Policy File即可，具体方法上面部分有提到。   
经检验，hadoop1.com节点安装了JCE Policy文件后，hdfs的命令可以正常使用了。

## 5. 怎样让hdfs之外的账户（hbase、mapred等）通过验证？ ##

1.    
    
2.  以`hbase@GUIZHOU.COM`来访问HDFS
    
    经过上面的配置，我们可以通过命令`kinit hdfs`来以`hdfs`的身份访问HDFS，那么如果我想以`hbase`的身份来访问HDFS呢？
    
    尝试一下：
    
    > \[root@hadoop1 ~\]\# kinit hbase   
    > kinit: Client not found in Kerberos database while getting initial credentials
    
    报错: 不存在`hbase`这个principal。
    
    在`kadmin.local`中通过命令`listprincs`可以看出，不存在`hbase@GUIZHOU.COM`这个principal，但是存在以下5个相关的principal：
    
    > \[root@hadoop1 ~\]\# kadmin.local   
    > Authenticating as principal hdfs/admin@GUIZHOU.COM with password.   
    > kadmin.local: listprincs   
    > hbase/hadoop1.com@GUIZHOU.COM   
    > hbase/hadoop2.com@GUIZHOU.COM   
    > hbase/hadoop3.com@GUIZHOU.COM   
    > hbase/hadoop4.com@GUIZHOU.COM   
    > hbase/hadoop5.com@GUIZHOU.COM
    
      
      
    再来试一下：
    
    > \[root@hadoop1 ~\]\# kinit hbase/hadoop1.com@GUIZHOU.COM   
    > Password for hbase/hadoop1.com@GUIZHOU.COM:
    
    哎呀，它让我输入`hbase/hadoop1.com@GUIZHOU.COM`这个principal的密码，但是这个principal不是我们创建的，是Cloudera Manager自己创建的，我们哪里知道它的密码呢！咋办？
    
    回想一下，`hdfs`这个principal是我们自己创建的，因此我们也如法炮制地创建一个`hbase`的principal，如下：
    
    > \[root@hadoop1 ~\]\# kadmin.local   
    > Authenticating as principal root/admin@GUIZHOU.COM with password.   
    > kadmin.local: addprinc hbase@GUIZHOU.COM   
    > WARNING: no policy specified for hbase@GUIZHOU.COM; defaulting to no policy   
    > Enter password for principal "hbase@GUIZHOU.COM":     密码设为『hbase-1234』   
    > Re-enter password for principal "hbase@GUIZHOU.COM":   
    > Principal "hbase@GUIZHOU.COM" created.
    
      
      
    现在，我们再试一下：
    
    > \[root@hadoop1 ~\]\# kinit hbase   
    > Password for hbase@GUIZHOU.COM:   
    > \[root@hadoop1 ~\]\# hdfs dfs -put UnlimitedJCEPolicyJDK7.zip /hbase   
    > \[root@hadoop1 ~\]\# hdfs dfs -ls /hbase   
    > Found 9 items   
    > drwxr-xr-x - hbase hbase 0 2015-09-07 15:05 /hbase/.tmp   
    > \-rw-r--r-- 3 hbase hbase 7426 2015-09-21 16:47 /hbase/UnlimitedJCEPolicyJDK7.zip   
    > drwxr-xr-x - hbase hbase 0 2015-09-18 15:51 /hbase/WALs   
    > drwxr-xr-x - hbase hbase 0 2015-09-17 21:59 /hbase/archive   
    > drwxr-xr-x - hbase hbase 0 2015-06-24 17:36 /hbase/corrupt   
    > drwxr-xr-x - hbase hbase 0 2015-09-07 15:05 /hbase/data   
    > \-rw-r--r-- 3 hbase hbase 42 2015-04-02 16:01 /hbase/hbase.id   
    > \-rw-r--r-- 3 hbase hbase 7 2015-04-02 16:01 /hbase/hbase.version   
    > drwxr-xr-x - hbase hbase 0 2015-09-18 15:51 /hbase/oldWALs
    
    可见，在获取了`hdfs@GUIZHOU`的credentials之后，我们可以直接以`hbase@GUIZHOU.COM`这个principal来访问HDFS，即使此时的Linux账户不是`hbase`。
    
    注意：不要试图使用`sudo -u hbase xxx`来以`hbase`的身份操作HDFS，那样反而不行。
    
    > \[root@hadoop1 ~\]\# sudo -u hbase hdfs dfs -ls /hbase   
    > 15/09/21 16:51:24 WARN security.UserGroupInformation: PriviledgedActionException as:hbase (auth:KERBEROS) cause:javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]   
    > 15/09/21 16:51:24 WARN ipc.Client: Exception encountered while connecting to the server : javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]   
    > 15/09/21 16:51:24 WARN security.UserGroupInformation: PriviledgedActionException as:hbase (auth:KERBEROS) cause:java.io.IOException: javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]   
    > ls: Failed on local exception: java.io.IOException: javax.security.sasl.SaslException: GSS initiate failed \[Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)\]; Host Details : local host is: "hadoop1.com/59.215.222.3"; destination host is: "hadoop5.com":8020;
    
      
    
3.  以`hbase@GUIZHOU.COM`来提交YARN Job   
    接着上面的第1点（在`root`Linux账户下，且已经取得了`hbase@GUIZHOU.COM`的credentials），我们继续:   
    
    
    > \[root@hadoop1 spark\]\# ./submit.sh   
    > 15/09/21 17:03:19 INFO SecurityManager: Changing view acls to: root   
    > 15/09/21 17:03:19 INFO SecurityManager: Changing modify acls to: root   
    > 15/09/21 17:03:19 INFO SecurityManager: SecurityManager: authentication disabled; ui acls disabled; users with view permissions: Set(root); users with modify permissions: Set(root)

## 6. 长时间运行的Job怎样应对ticket expire的问题 ##

参考 [Configuring YARN for Long-running Applications][]

[给我写信][Link 5]   
[GitHub][]

![此处输入图片的描述][mini.png]

`Kerberos`

--------------------

# 前提 #

我们再看一下我们KDC的配置。

*  hadopo\[1-5\].com主机上 */etc/krb5.conf* 文件的内容

[logging]
        default = FILE:/var/log/krb5libs.log
        kdc = FILE:/var/log/krb5kdc.log
        admin_server = FILE:/var/log/kadmind.log
        
        [libdefaults]
        default_realm = GUIZHOU.COM
        dns_lookup_realm = false
        dns_lookup_kdc = false
        ticket_lifetime = 24h
        renew_lifetime = 7d
        forwardable = true
        renewable = true
        
        [realms]
        GUIZHOU.COM = { 
        kdc = hadoop1.com
        admin_server = hadoop1.com
        }
        
        [domain_realm]
        hadoop1.com = GUIZHOU.COM
        hadoop2.com = GUIZHOU.COM
        hadoop3.com = GUIZHOU.COM
        hadoop4.com = GUIZHOU.COM
        hadoop5.com = GUIZHOU.COM

*  hadoop1.com主机上 */var/kerberos/krb5kdc/kdc.conf* 文件的内容

[kdcdefaults]
        kdc_ports = 88
        kdc_tcp_ports = 88
        [realms]
        GUIZHOU.COM = { 
        #master_key_type = aes256-cts
        acl_file = /var/kerberos/krb5kdc/kadm5.acl
        dict_file = /usr/share/dict/words
        admin_keytab = /var/kerberos/krb5kdc/kadm5.keytab
        supported_enctypes = aes256-cts:normal aes128-cts:normal des3-hmac-sha1:normal arcfour-hmac:normal des-hmac-sha1:normal des-cbc-md5:normal des-cbc-crc:normal
        max_life = 1d
        max_renewable_life = 7d
        }

# 配置过程 #

## 安装JCE Policy File ##

为Cloudera Hadoop集群安装JCE Policy File的过程可以 [参考这里][Link 1] 。

## 创建Cloudera Manager Principal ##

在KDC server主机上，创建一个名为『cloudera-scm』的principal，并将其密码设为『cloudera-scm-1234』。执行命令：

[root@hadoop1 ~]# kadmin.local 
        Authenticating as principal root/admin@GUIZHOU.COM with password.
        kadmin.local: addprinc -pw cloudera-scm-1234 cloudera-scm/admin@GUIZHOU.COM
        WARNING: no policy specified for cloudera-scm/admin@GUIZHOU.COM; defaulting to no policy
        Principal "cloudera-scm/admin@GUIZHOU.COM" created.

通过执行`kadmin.local`中的`listprincs`命令可以看到创建了一个名为『cloudera-scm/admin@GUIZHOU.COM』的principal：

kadmin.local: listprincs
        K/M@GUIZHOU.COM
        admin/admin@GUIZHOU.COM
        cloudera-scm/admin@GUIZHOU.COM
        kadmin/admin@GUIZHOU.COM
        kadmin/changepw@GUIZHOU.COM
        kadmin/hadoop1.com@GUIZHOU.COM
        krbtgt/GUIZHOU.COM@GUIZHOU.COM
        xiaotao@GUIZHOU.COM

## 通过CDH Wizard来启用Kerberos ##

在Cloudera Manager界面上点击Cluster名称右边的『Enable Kerberos』选项。点击之后，会要求你确认以下的事项：

> 1.  KDC已经安装好并且正在运行；   
>       
>     
> 2.  将KDC配置为允许renewable tickets with non-zerolifetime;   
>     方法：在kdc.conf文件中如下配置   
>     
>     
>         [kdcdefaults]
>                kdc_ports = 88
>                kdc_tcp_ports = 88
>                
>                [realms]
>                GUIZHOU.COM = { 
>                acl_file = /var/kerberos/krb5kdc/kadm5.acl
>                dict_file = /usr/share/dict/words
>                admin_keytab = /var/kerberos/krb5kdc/kadm5.keytab
>                supported_enctypes = aes256-cts:normal aes128-cts:normal des3-hmac-sha1:normal arcfour-hmac:normal des-hmac-sha1:normal des-cbc-md5:normal des-cbc-crc:normal
>                max_life = 1d
>                max_renewable_life = 7d
>                }
> 
> 其中必要的选项是`kdc_tcp_ports`、`max_life`和`max_renewable_life`。   
>   
>   
> 3. 在Cloudera Manager Server上安装`openldap-clients`   
>   
>   
> 4. 为Cloudera Manager创建一个principal，使其能够有权限在KDC中创建其他的principals，这一步在上一节中已经完成了。

点击continue，进入[下一页][Link 2]进行配置，要注意的是：这里的『Kerberos Encryption Types』必须跟KDC实际支持的加密类型匹配（即kdc.conf中的值）。

点击continue，进入下一页，这一页中可以不勾选『Manage krb5.conf through Cloudera Manager』。

点击continue，进入下一页，输入Cloudera Manager Principal（就我们之前创建的*cloudera-scm/admin@GUIZHOU.COM* ）的username和password。

点击continue，进入下一页，导入KDC Account Manager Credentials。

点击continue，进入下一页，restart cluster并且enable Kerberos。

大功告成！现在，Cloudera Manager Server/Hosts可以重启，但是CDH cluster还不能启动。

## 创建HDFS超级用户 ##

[root@hadoop1 ~]# kadmin.local 
        Authenticating as principal root/admin@GUIZHOU.COM with password.
        kadmin.local: addprinc hdfs@GUIZHOU.COM
        WARNING: no policy specified for hdfs@GUIZHOU.COM; defaulting to no policy
        Enter password for principal "hdfs@GUIZHOU.COM": 
        Re-enter password for principal "hdfs@GUIZHOU.COM": 
        Principal "hdfs@GUIZHOU.COM" created.

这里我们为principal『hdfs@GUIZHOU.com』设置了密码『hdfs-1234』。

为了能够以hdfs的身份来运行命令，必须为 *hdfs* principal 获取Kerberos credentials。因此，运行命令：

[root@hadoop1 ~]# kinit hdfs@GUIZHOU.COM

## 看看现在KDC database中有哪些principals ##

可以看到，很多的pincipals都是CDH帮我们添加进去的。

## 为每一个User Account创建Kerberos Principal ##

## 确认Kerberized Hadoop Cluster可以正常使用 ##

## 确保其他组件（ZooKeeper / HBase等）正常运行 ##

现在虽然HDFS可以正常运行，YARN job也可以正常运行，但是如果启动HBase，那么会发现HBase不能正常启动。

所以，在安装了Kerberized CDH 后，我们还要针对HBase（以及ZooKeeper）进行配置，具体步骤参考 [HBase Authentication][]

# 常见问题 #

参考 [Troubleshooting Authentication Issues][]

## 1. 运行任何hadoop命令都会失败 ##

例如，以 *hdfs* 的身份运行`hadoop dfs -ls /`，出现以下异常：

如果出现这种情况，逐项检查：

## 2. hdfs用户无法提交一个Job ##

## 3. YARN job运行时无法创建缓存目录 ##

解决方法：   
在每一个NodeManager节点上删除该用户的缓存目录，对于用户`hdfs`，是`/data/data/yarn/nm/usercache/hdfs`。

原因：   
该缓存目录在集群进入Kerberos状态前就已经存在了。例如当我们还没为集群Kerberos支持的时候，就用该用户跑过YARN应用。也许这是一个[bug][]

## 4. 个别节点无法通过Kerberos验证 ##

## 5. 怎样让hdfs之外的账户（hbase、mapred等）通过验证？ ##

## 6. 长时间运行的Job怎样应对ticket expire的问题 ##

参考 [Configuring YARN for Long-running Applications][]

[GitHub]: https://github.com/TaoXiao
[Configuring Authentication in Clouera Manager]: http://www.cloudera.com/content/cloudera/en/documentation/core/v5-3-x/topics/cm_sg_authentication.html
[Understanding Kerberos]: https://www.zybuluo.com/xtccc/note/176028
[Instlling Kerberos]: https://www.zybuluo.com/xtccc/note/175999
[Troubleshooting Authentication Issues]: http://www.cloudera.com/content/cloudera/en/documentation/core/v5-3-x/topics/cm_sg_sec_troubleshooting.html
[Configuring YARN for Long-running Applications]: http://www.cloudera.com/content/cloudera/en/documentation/core/v5-3-x/topics/cm_sg_yarn_long_jobs.html
[Java Cryptography Extension _JCE_ Unlimited Strength Jurisdiction Policy File]: http://www.oracle.com/technetwork/java/javase/downloads/index.html
[Link 1]: http://www.cloudera.com/content/cloudera/en/documentation/core/v5-3-x/topics/cm_sg_s2_jce_policy.html
[Link 2]: http://7xjcu2.com1.z0.glb.clouddn.com/QQ20150918-1@2x.png
[HBase Authentication]: https://www.zybuluo.com/xtccc/note/179666
[Link 3]: http://7xjcu2.com1.z0.glb.clouddn.com/QQ20150920-2@2x.png
[bug]: https://community.cloudera.com/t5/Batch-Processing-and-Workflow/Can-t-create-directory-yarn-nm-usercache-urika-appcache/td-p/24891
[Link 4]: http://7xjcu2.com1.z0.glb.clouddn.com/QQ20150921-1@2x.png
[Link 5]: http://mail.qq.com/cgi-bin/qm_share?t=qm_mailme&email=Xys_MB84LTY7J3E8MQ
[mini.png]: http://7xjcu2.com1.z0.glb.clouddn.com/mini.png