今天尝试在Hadoop 2.x开发集群上配置Kerberos，遇到一些问题，记录一下

设置hadoop security

core-site.xml

        
           hadoop.security.authentication
           kerberos
        
        
           hadoop.security.authorization
           true

hadoop.security.authentication默认是simple方式，也就是基于linux操作系统的验证方式，用户端调用whoami命令，然后RPC call给服务端，恶意用户很容易在其他host伪造一个相同的用户。这里我们改为kerberos。

设置hdfs security

hdfs-site.xml

        
                dfs.block.access.token.enable
                true
        
        
                dfs.https.enable
                false
        
        
                dfs.namenode.https-address
                dev80.hadoop:50470
        
        
                dfs.https.port
                50470
        
        
                dfs.namenode.keytab.file
                /etc/hadoop.keytab
        
        
                dfs.namenode.kerberos.principal
                hadoop/_HOST@DIANPING.COM
        
        
                dfs.namenode.kerberos.https.principal
                host/_HOST@DIANPING.COM
        
        
                dfs.namenode.secondary.http-address
                dev80.hadoop:50090
        
        
                dfs.namenode.secondary.https-port
                50470
        
        
                dfs.namenode.secondary.keytab.file
                /etc/hadoop.keytab
        
        
                dfs.namenode.secondary.kerberos.principal
                hadoop/_HOST@DIANPING.COM
        
        
                dfs.namenode.secondary.kerberos.https.principal
                host/_HOST@DIANPING.COM
        
        
                dfs.datanode.data.dir.perm
                700
        
        
                dfs.datanode.address
                0.0.0.0:1003
        
        
                dfs.datanode.http.address
                0.0.0.0:1007
        
        
                dfs.datanode.https.address
                0.0.0.0:1005
        
        
                dfs.datanode.keytab.file
                /etc/hadoop.keytab
        
        
                dfs.datanode.kerberos.principal
                hadoop/_HOST@DIANPING.COM
        
        
                dfs.datanode.kerberos.https.principal
                host/_HOST@DIANPING.COM
        
        
                dfs.datanode.data.dir.perm
                700
        
        
                dfs.datanode.address
                0.0.0.0:1003
        
        
                dfs.datanode.http.address
                0.0.0.0:1007
        
        
                dfs.datanode.https.address
                0.0.0.0:1005
        
        
                dfs.datanode.keytab.file
                /etc/hadoop.keytab
        
        
                dfs.datanode.kerberos.principal
                hadoop/_HOST@DIANPING.COM
        
        
                dfs.datanode.kerberos.https.principal
                host/_HOST@DIANPING.COM
        
        
                dfs.web.authentication.kerberos.principal
                HTTP/_HOST@DIANPING.COM
        
        
              dfs.web.authentication.kerberos.keytab
              /etc/hadoop.keytab
              
                            The Kerberos keytab file with the credentials for the
                                  HTTP Kerberos principal used by Hadoop-Auth in the HTTP endpoint.

配置中有几点要注意的

1. dfs.datanode.address表示data transceiver RPC server所绑定的hostname或IP地址，如果开启security，端口号必须小于1024(privileged port)，否则的话启动datanode时候会报“Cannot start secure cluster without privileged resources”错误

2. principal中的instance部分可以使用'_HOST'标记，系统会自动替换它为全称域名

3. 如果开启了security, hadoop会对hdfs block data(由dfs.data.dir指定)做permission check，方式用户的代码不是调用hdfs api而是直接本地读block data，这样就绕过了kerberos和文件权限验证，管理员可以通过设置dfs.datanode.data.dir.perm来修改datanode文件权限，这里我们设置为700

namenode和secondary namenode都是以hadoop用户身份启动

datanode需要以root用户身份用jsvc来启动，而Hadoop 2.x自身带的jsvc是32位版本的，需要去jsvc官网上重新下载编译

wget http://mirror.esocc.com/apache//commons/daemon/binaries/commons-daemon-1.0.15-bin.tar.gz
cd src/native/unix; configure; make

生成jsvc 64位executable，把它拷贝到$HADOOP_HOME/libexec，然后需要在hadoop-env.sh中指定JSVC_HOME到此路径，否则会报错"It looks like you're trying to start a secure DN, but $JSVC_HOME isn't set. Falling back to starting insecure DN."

[hadoop@dev80 unix]$ file jsvc
jsvc: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped

mvn package

编译commons-daemon-1.0.15.jar，拷贝到$HADOOP_HOME/share/hadoop/hdfs/lib下，同时删除自带版本的commons-daemon jar包

hadoop-env.sh中修改

# The jsvc implementation to use. Jsvc is required to run secure datanodes.
export JSVC_HOME=/usr/local/hadoop/hadoop-2.1.0-beta/libexec
# On secure datanodes, user to run the datanode as after dropping privileges
export HADOOP_SECURE_DN_USER=hadoop
# The directory where pid files are stored. /tmp by default
export HADOOP_SECURE_DN_PID_DIR=/usr/local/hadoop
# Where log files are stored in the secure data environment.
export HADOOP_SECURE_DN_LOG_DIR=/data/logs

分发配置和jar到整个集群

用hadoop帐号启动namenode，然后切换到root，再启动datanode，发现namenode web页面上有显示"

Security is ON

"

启动secure datanode命令

  exec "$JSVC" \
           -Dproc_$COMMAND -outfile "$JSVC_OUTFILE" \
           -errfile "$JSVC_ERRFILE" \
           -pidfile "$HADOOP_SECURE_DN_PID" \
           -nodetach \
           -user "$HADOOP_SECURE_DN_USER" \
            -cp "$CLASSPATH" \
           $JAVA_HEAP_MAX $HADOOP_OPTS \
           org.apache.hadoop.hdfs.server.datanode.SecureDataNodeStarter "$@"

如果启动过程中有什么问题可以查看$JSVC_OUTFILE(默认是$HADOOP_LOG_DIR/jsvc.out) 和 $JSVC_ERRFILE（默认是$HADOOP_LOG_DIR/jsvc.err）信息来排错

设置yarn security

yarn-site.xml

        
                yarn.resourcemanager.keytab
                /etc/hadoop.keytab
        
        
                yarn.resourcemanager.principal
                hadoop/_HOST@DIANPING.COM
        
        
                yarn.nodemanager.keytab
                /etc/hadoop.keytab
        
        
                yarn.nodemanager.principal
                hadoop/_HOST@DIANPING.COM
        
        
                yarn.nodemanager.container-executor.class
                org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor
        
        
                yarn.nodemanager.linux-container-executor.group
                hadoop

container-executor默认是DefaultContainerExecutor，是以起Nodemanager的用户身份启动container的，切换为LinuxContainerExecutor会以提交application的用户身份来启动，它使用一个setuid可执行文件来启动和销毁container

这个可执行文件在bin/container-executor，不过Hadoop默认带的还是32位版本，所以需要重新编译

下载Hadoop 2.x source code

mvn package -Pdist,native -DskipTests -Dtar -Dcontainer-executor.conf.dir=/etc

注：container-executor.conf.dir必须显示注明，它表示setuid可执行文件依赖的配置文件(container-executor.cfg)路径，默认会在$HADOOP_HOME/etc/hadoop下，不过由于该文件需要父目录和以上的目录的owner都为root，要不然会有以下报错，所以为了方便我们设置为/etc

Caused by: org.apache.hadoop.util.Shell$ExitCodeException: File /usr/local/hadoop/hadoop-2.1.0-beta/etc/hadoop must be owned by root, but is owned by 500
        at org.apache.hadoop.util.Shell.runCommand(Shell.java:458)
        at org.apache.hadoop.util.Shell.run(Shell.java:373)
        at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:578)
        at org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor.init(LinuxContainerExecutor.java:147)

默认的寻找configuration路径

[root@dev80 bin]# strings container-executor  | grep etc
../etc/hadoop/container-executor.cfg

看出来是默认加载$HADOOP_HOME/etc/hadoop/container-executor.cfg

加上container-executor.conf.dir=/etc 再编译后

[hadoop@dev80 bin]$ strings container-executor | grep etc
/etc/container-executor.cfg

container-executor.cfg中设置

yarn.nodemanager.linux-container-executor.group=hadoop
min.user.id=499

其中min.user.id表示启动container的最小uid，如果有低于这个值的uid启动task，就会fail掉。一般Centos，RHEL用户帐号uid是从500开始

将container-executor拷贝到$HADOOP_HOME/bin

chown root:hadoop container-executor /etc/container-executor.cfg
chmod 4750 container-executor
chmod 400 /etc/container-executor.cfg

同步配置文件到整个集群，用hadoop帐号启动ResourceManager和Nodemanager

注意：为了方便测试，先不要将配置分发到所有集群，而是分到一台，然后起RM和一台NM，一切都okay后，再同步到所有host

设置jobhistory server security

mapred-site.xml

        
                mapreduce.jobhistory.keytab
                /etc/hadoop.keytab
        
        
                mapreduce.jobhistory.principal
                hadoop/_HOST@DIANPING.COM

启动JobHistoryServer

sbin/mr-jobhistory-daemon.sh start historyserver

执行命令kinit,获得一张tgt(ticket granting ticket)

[hadoop@dev80 hadoop]$ kinit -r 24l -k -t /home/hadoop/.keytab hadoop
[hadoop@dev80 hadoop]$ klist
Ticket cache: FILE:/tmp/krb5cc_500
Default principal: hadoop@DIANPING.COM
Valid starting     Expires            Service principal
09/11/13 15:25:34  09/12/13 15:25:34  krbtgt/DIANPING.COM@DIANPING.COM
 renew until 09/12/13 15:25:34

其中/tmp/krb5cc_500就是kerberos ticket cache, 默认会在/tmp下创建名字为“krb5cc_”加上uid的文件，此处500表示hadoop帐号的uid

[hadoop@dev80 hadoop]$ getent passwd
hadoop:x:500:500::/home/hadoop:/bin/bash

用户也可以通过设置export KRB5CCNAME=/tmp/krb5cc_500到环境变量来指定ticket cache路径

用完之后可以使用kdestroy命令来销毁掉该ticket cache

[hadoop@dev80 hadoop]$ kdestroy 
[hadoop@dev80 hadoop]$ klist
klist: No credentials cache found (ticket cache FILE:/tmp/krb5cc_500)

如果本地没有ticket cache，会报如下错误

13/09/11 16:21:35 ERROR security.UserGroupInformation: PriviledgedActionException as:hadoop (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)]

附上/etc/hadoop.keytab中的principal，都是service principal

[hadoop@dev80 hadoop]$ klist -k -t /etc/hadoop.keytab
Keytab name: WRFILE:/etc/hadoop.keytab
KVNO Timestamp         Principal
---- ----------------- --------------------------------------------------------
   1 06/17/12 22:01:24 hadoop/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 hadoop/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 hadoop/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 hadoop/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 hadoop/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 hadoop/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 host/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 host/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 host/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 host/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 host/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 host/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 HTTP/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 HTTP/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 HTTP/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 HTTP/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 HTTP/dev80.hadoop@DIANPING.COM
   1 06/17/12 22:01:24 HTTP/dev80.hadoop@DIANPING.COM

/home/hadoop/.keytab下放user principal

[hadoop@dev80 hadoop]$ klist -k -t /home/hadoop/.keytab
Keytab name: WRFILE:/home/hadoop/.keytab
KVNO Timestamp         Principal
---- ----------------- --------------------------------------------------------
   1 04/11/12 13:56:29 hadoop@DIANPING.COM

由于keytab相当于有了永久凭证，不需要提供密码(如果修改kdc中的principal的密码，则该keytab就会失效)，所以其他用户如果对该文件有读权限，就可以冒充keytab中指定的用户身份访问hadoop，所以keytab文件需要确保只对owner有读权限(0400)

本文链接http://blog.csdn.net/lalaguozhe/article/details/11570009，转载请注明

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