zoukankan      html  css  js  c++  java
  • 大数据学习之路之Hadoop

    Hadoop介绍

    一、简介

    Hadoop是一个开源的分布式计算平台,用于存储大数据,并使用MapReduce来处理。Hadoop擅长于存储各种格式的庞大的数据,任意的格式甚至非结构化的处理。两个核心:

    • HDFS:Hadoop分布式文件系统(Hadoop Distributed File System),具有高容错性和伸缩性,使用java开发
    • MapReduce:Google MapReduce的开源实现,分布式编程模型使用户更方便的开发并行应用

    使用Hadoop可以轻松的组织计算机资源,从而搭建自己的分布式计算平台,并且可以充分利用集群的计算 和存储能力,完成海量数据的处理。

    二、Hadoop的优势

    1. 高可靠性:Hadoop按位存储和处理数据的能力具有很高的可靠性
    2. 高拓展性:Hadoop是在可用的计算机集簇间分配数据完成计算任务的,这些集簇可以拓展到数以千计的节点中
    3. 高效性:Hadoop能够在节点之间动态地移动数据,以保证各个节点的动态平衡,因此其处理速度非常快
    4. 高容错性:Hadoop能够自动保存数据的多份副本,并且能够自动将失败的任务重新分配

    三、关联项目

    • Common:为Hadoop及其子项目提供支持的常用工具,主要包括FileSystem,RPC和串行化库。
    • Avro:Avro用于数据序列化的系统。提供了丰富的数据结构类型、快速可压缩的二进制格式、存储持久性数据的文件集、远程调用RPC的功能和简单的动态语言集成功能。
    • MapReduce:是一种编程模型,用于大规模数据集(大于1TB)的并行运算。
    • HDFS:分布式文件系统。
    • YRAN:分布式资源管理。
    • Chukwa:开源的数据收集系统,用于监控和分析大型分布式系统的数据。
    • Hive:一个建立在Hadoop基础之上的数据仓库,它提供了一些用于对Hadoop文件中的数据集进行数据整理、特殊查询和分析存储的工具。Hive提供一种结构化数据的机制,支持类似传统RDBMS的SQL语言的查询语言来帮助那些熟悉SQL的用户查询Hadoop中的数据,该查询语言成为Hive SQL。
    • Hbase:一个分布式的、面向列的开源数据库,适合非结构化的数据存储。主要用于需要随机访问、实时读写的大数据。
    • Pig:是一个对大型数据集进行分析、评估的平台。Pig最突出的优势是它的结构能够经受住高度并行化的检验。
    • Zookeeper:为分布式应用设计的协调服务,主要为用户提供同步、配置管理、分组和命令等服务。

    四、编译安装Hadoop

    因为我是用的是32位系统,官方预编译版本只有64位的,无法使用,所以得编译源代码。

    根据编译文件BUILDING.txt内容,安装hadoop之前需要保证有以下工具:

    Hadoop编译说明书
    
    需要:
    Unix 系统
    JDK1.8
    maven 3.3或更高
    ProtoBuffer 2.5.0
    CMake 3.1或更新(如果需要编译本地代码)
    Zlib develop(如果需要编译本地代码)
    openssl devel(如果编译原生hadoop-pipe,并获得最佳的HDFS加密性能)
    Linux FUSE(用户空间的文件系统) 2.6或更高(如果编译fuse_dfs)
    第一次编译需要网络保持连接(获取所有的maven和Hadoop需要的依赖)
    Python(发布文档需要)
    bats(用于shell代码测试)
    Node.js / bower / Ember-cli(用于编译前端UI界面)
    ---------------------------------------------------------------------
    获得具有所有工具的环境的最简单方法是通过Docker提供的配置。
    这就需要一本最近的docker版本1.4.1或者更高的可以正常工作的版本
    
    在Linux上,你可以运行下面的命名安装Docker
    $ ./start-build-env.sh
    接下来显示的提示是位于源树的已安装版本,并且已安装和配置了所有必需的测试和构建工具。
    请注意,在此docker环境中,您只能从您开始的位置访问Hadoop源树。因此如果你想运行
    dev-support/bin/test-patch /path/to/my.patch
    那么这个patch文件必须放在hadoop源树中。
    
    在ubuntu中清楚并安装所需的软件包:
    Oracle JDK 1.8 (首选)
      $ sudo apt-get purge openjdk*
      $ sudo apt-get install software-properties-common
      $ sudo add-apt-repository ppa:webupd8team/java
      $ sudo apt-get update
      $ sudo apt-get install oracle-java8-installer
    Maven
      $ sudo apt-get -y install maven
    本地依赖包
      $ sudo apt-get -y install build-essential autoconf automake libtool cmake zlib1g-dev pkg-config libssl-dev
    ProtocolBuffer 2.5.0 (必须)
      $ sudo apt-get -y install protobuf-compiler
      
    
    # 1.下载源码
    wget https://www.apache.org/dyn/closer.cgi/hadoop/common/hadoop-3.1.2/hadoop-3.1.2-src.tar.gz
    # 2.解压
    tar -zxcf hadoop-3.1.2-src.tar.gz
    cd hadoop-3.1.2-src
    # 3.mvn编译
    mvn package -Pdist,native -DskipTests -Dtar
    

    编译这个玩意儿断断续续用了3天时间,下面是遇到的问题总结记录一下。

    问题1:

    mvn package -Pdist,native -DskipTests -Dtar的时候编译失败:

    [ERROR] Failed to execute goal org.codehaus.mojo:native-maven-plugin:1.0-alpha-8:javah (default) on project hadoop-common: Error running javah command: Error executing command line. Exit code:2 -> [Help 1]
    

    解决:

    vim hadoop-common-project/hadoop-common/pom.xml将javah的执行路径改为绝对路径

    <javahPath>${env.JAVA_HOME}/bin/javah</javahPath>
    改为
    <javahPath>/usr/bin/javah</javahPath>
    # 具体的路径需要对应你机器上的真实路径
    

    问题2:

    mvn package -Pdist,native -DskipTests -Dtar的时候编译失败:

    [ERROR] Failed to execute goal org.apache.hadoop:hadoop-maven-plugins:3.1.2:cmake-compile (cmake-compile) on project hadoop-common: CMake failed with error code 1 -> [Help 1]
    org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.hadoop:hadoop-maven-plugins:3.1.2:cmake-compile (cmake-compile) on project hadoop-common: CMake failed with error code 1
    

    解决:

    cmake版本不对,安装cmake3.0版本:

    # download
    wget https://cmake.org/files/v3.0/cmake-3.0.0.tar.gz
    tar -zxvf cmake-3.0.0.tar.gz
    cd cmake-3.0.0
    ./configure
    make
    sudo apt-get install checkinstall
    sudo checkinstall
    sudo make install
    # 建立软链接
    sudo ln -s bin/* /usr/bin/ 
    

    还是不行。使用mvn package -Pdist,native -DskipTests -Dtar -e -X打印所有日志,可以找到:

    [INFO] Running cmake /home/wangjun/software/hadoop-3.1.2-src/hadoop-common-project/hadoop-common/src -DGENERATED_JAVAH=/home/wangjun/software/hadoop-3.1.2-src/hadoop-common-project/hadoop-common/target/native/javah -DJVM_ARCH_DATA_MODEL=32 -DREQUIRE_BZIP2=false -DREQUIRE_ISAL=false -DREQUIRE_OPENSSL=false -DREQUIRE_SNAPPY=false -DREQUIRE_ZSTD=false -G Unix Makefiles
    [INFO] with extra environment variables {}
    [WARNING] Soft-float JVM detected
    [WARNING] CMake Error at /home/wangjun/software/hadoop-3.1.2-src/hadoop-common-project/hadoop-common/HadoopCommon.cmake:182 (message):
    [WARNING]   Soft-float dev libraries required (e.g.  'apt-get install libc6-dev-armel'
    [WARNING]   on Debian/Ubuntu)
    [WARNING] Call Stack (most recent call first):
    [WARNING]   CMakeLists.txt:26 (include)
    [WARNING] 
    [WARNING] 
    [WARNING] -- Configuring incomplete, errors occurred!
    [WARNING] See also "/home/wangjun/software/hadoop-3.1.2-src/hadoop-common-project/hadoop-common/target/native/CMakeFiles/CMakeOutput.log".
    [WARNING] See also "/home/wangjun/software/hadoop-3.1.2-src/hadoop-common-project/hadoop-common/target/native/CMakeFiles/CMakeError.log".
    

    查看hadoop-common-project/hadoop-common/target/native/CMakeFiles/CMakeError.log日志,看到报错:

    gnu/stubs-soft.h: No such file or directory
    

    解决方案:更改hadoop-common-project/hadoop-common/HadoopCommon.cmake,将两处-mfloat-abi=softfp改为-mfloat-abi=hard,参考:https://blog.csdn.net/wuyusheng314/article/details/79428996https://stackoverflow.com/questions/49139125/fatal-error-gnu-stubs-soft-h-no-such-file-or-directory。(最好是重新解压原始包更改完重新编译,要不然可能会出错)

    这个改完又有了新问题,编译Apache Hadoop MapReduce NativeTask是报错

    [WARNING] /usr/bin/ranlib libgtest.a
    [WARNING] make[2]: Leaving directory '/home/wangjun/software/hadoop-3.1.2-src/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-nativetask/target/native'
    [WARNING] /usr/local/bin/cmake -E cmake_progress_report /home/wangjun/software/hadoop-3.1.2-src/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-nativetask/target/native/CMakeFiles  1
    [WARNING] [  7%] Built target gtest
    [WARNING] make[1]: Leaving directory '/home/wangjun/software/hadoop-3.1.2-src/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-nativetask/target/native'
    [WARNING] /tmp/ccpXG9td.s: Assembler messages:
    [WARNING] /tmp/ccpXG9td.s:2040: Error: bad instruction `bswap r5'
    [WARNING] /tmp/ccpXG9td.s:2063: Error: bad instruction `bswap r1'
    [WARNING] make[2]: *** [CMakeFiles/nativetask.dir/build.make:79: CMakeFiles/nativetask.dir/main/native/src/codec/BlockCodec.cc.o] Error 1
    [WARNING] make[2]: *** Waiting for unfinished jobs....
    [WARNING] make[1]: *** [CMakeFiles/Makefile2:96: CMakeFiles/nativetask.dir/all] Error 2
    [WARNING] make[1]: *** Waiting for unfinished jobs....
    [WARNING] /tmp/ccBbS5rL.s: Assembler messages:
    [WARNING] /tmp/ccBbS5rL.s:1959: Error: bad instruction `bswap r5'
    [WARNING] /tmp/ccBbS5rL.s:1982: Error: bad instruction `bswap r1'
    [WARNING] make[2]: *** [CMakeFiles/nativetask_static.dir/build.make:79: CMakeFiles/nativetask_static.dir/main/native/src/codec/BlockCodec.cc.o] Error 1
    [WARNING] make[2]: *** Waiting for unfinished jobs....
    [WARNING] /tmp/cc6DHbGO.s: Assembler messages:
    [WARNING] /tmp/cc6DHbGO.s:979: Error: bad instruction `bswap r2'
    [WARNING] /tmp/cc6DHbGO.s:1003: Error: bad instruction `bswap r3'
    [WARNING] make[2]: *** [CMakeFiles/nativetask_static.dir/build.make:125: CMakeFiles/nativetask_static.dir/main/native/src/codec/Lz4Codec.cc.o] Error 1
    [WARNING] make[1]: *** [CMakeFiles/Makefile2:131: CMakeFiles/nativetask_static.dir/all] Error 2
    [WARNING] make: *** [Makefile:77: all] Error 2
    
    

    看错误应该是指令问题,google一番后,找到解决方案:https://issues.apache.org/jira/browse/HADOOP-14922https://issues.apache.org/jira/browse/HADOOP-11505

    编辑primitives.h文件,根据https://issues.apache.org/jira/secure/attachment/12693989/HADOOP-11505.001.patch里面的git log修改后重新编译。

    经历了3天的折磨,终于成功了!来,看看成功后的显示:

    [INFO] No site descriptor found: nothing to attach.
    [INFO] ------------------------------------------------------------------------
    [INFO] Reactor Summary for Apache Hadoop Main 3.1.2:
    [INFO] 
    [INFO] Apache Hadoop Main ................................. SUCCESS [  3.532 s]
    [INFO] Apache Hadoop Build Tools .......................... SUCCESS [  6.274 s]
    [INFO] Apache Hadoop Project POM .......................... SUCCESS [  3.668 s]
    [INFO] Apache Hadoop Annotations .......................... SUCCESS [  5.743 s]
    [INFO] Apache Hadoop Assemblies ........................... SUCCESS [  1.739 s]
    [INFO] Apache Hadoop Project Dist POM ..................... SUCCESS [  4.782 s]
    [INFO] Apache Hadoop Maven Plugins ........................ SUCCESS [ 10.777 s]
    [INFO] Apache Hadoop MiniKDC .............................. SUCCESS [  5.156 s]
    [INFO] Apache Hadoop Auth ................................. SUCCESS [ 18.468 s]
    [INFO] Apache Hadoop Auth Examples ........................ SUCCESS [  8.293 s]
    [INFO] Apache Hadoop Common ............................... SUCCESS [03:15 min]
    [INFO] Apache Hadoop NFS .................................. SUCCESS [ 14.700 s]
    [INFO] Apache Hadoop KMS .................................. SUCCESS [ 15.340 s]
    [INFO] Apache Hadoop Common Project ....................... SUCCESS [  0.876 s]
    [INFO] Apache Hadoop HDFS Client .......................... SUCCESS [ 46.540 s]
    [INFO] Apache Hadoop HDFS ................................. SUCCESS [02:34 min]
    [INFO] Apache Hadoop HDFS Native Client ................... SUCCESS [ 12.125 s]
    [INFO] Apache Hadoop HttpFS ............................... SUCCESS [ 20.005 s]
    [INFO] Apache Hadoop HDFS-NFS ............................. SUCCESS [  8.934 s]
    [INFO] Apache Hadoop HDFS-RBF ............................. SUCCESS [01:08 min]
    [INFO] Apache Hadoop HDFS Project ......................... SUCCESS [  0.892 s]
    [INFO] Apache Hadoop YARN ................................. SUCCESS [  0.879 s]
    [INFO] Apache Hadoop YARN API ............................. SUCCESS [ 25.531 s]
    [INFO] Apache Hadoop YARN Common .......................... SUCCESS [01:57 min]
    [INFO] Apache Hadoop YARN Registry ........................ SUCCESS [ 14.521 s]
    [INFO] Apache Hadoop YARN Server .......................... SUCCESS [  0.920 s]
    [INFO] Apache Hadoop YARN Server Common ................... SUCCESS [ 23.432 s]
    [INFO] Apache Hadoop YARN NodeManager ..................... SUCCESS [ 28.782 s]
    [INFO] Apache Hadoop YARN Web Proxy ....................... SUCCESS [  9.515 s]
    [INFO] Apache Hadoop YARN ApplicationHistoryService ....... SUCCESS [ 14.077 s]
    [INFO] Apache Hadoop YARN Timeline Service ................ SUCCESS [ 12.728 s]
    [INFO] Apache Hadoop YARN ResourceManager ................. SUCCESS [ 51.338 s]
    [INFO] Apache Hadoop YARN Server Tests .................... SUCCESS [  8.675 s]
    [INFO] Apache Hadoop YARN Client .......................... SUCCESS [ 13.937 s]
    [INFO] Apache Hadoop YARN SharedCacheManager .............. SUCCESS [ 10.853 s]
    [INFO] Apache Hadoop YARN Timeline Plugin Storage ......... SUCCESS [ 12.546 s]
    [INFO] Apache Hadoop YARN TimelineService HBase Backend ... SUCCESS [  1.069 s]
    [INFO] Apache Hadoop YARN TimelineService HBase Common .... SUCCESS [ 17.176 s]
    [INFO] Apache Hadoop YARN TimelineService HBase Client .... SUCCESS [ 15.662 s]
    [INFO] Apache Hadoop YARN TimelineService HBase Servers ... SUCCESS [  0.901 s]
    [INFO] Apache Hadoop YARN TimelineService HBase Server 1.2  SUCCESS [ 17.512 s]
    [INFO] Apache Hadoop YARN TimelineService HBase tests ..... SUCCESS [ 17.327 s]
    [INFO] Apache Hadoop YARN Router .......................... SUCCESS [ 14.430 s]
    [INFO] Apache Hadoop YARN Applications .................... SUCCESS [  1.990 s]
    [INFO] Apache Hadoop YARN DistributedShell ................ SUCCESS [ 10.400 s]
    [INFO] Apache Hadoop YARN Unmanaged Am Launcher ........... SUCCESS [  7.210 s]
    [INFO] Apache Hadoop MapReduce Client ..................... SUCCESS [  2.549 s]
    [INFO] Apache Hadoop MapReduce Core ....................... SUCCESS [ 38.022 s]
    [INFO] Apache Hadoop MapReduce Common ..................... SUCCESS [ 35.908 s]
    [INFO] Apache Hadoop MapReduce Shuffle .................... SUCCESS [ 15.180 s]
    [INFO] Apache Hadoop MapReduce App ........................ SUCCESS [ 18.915 s]
    [INFO] Apache Hadoop MapReduce HistoryServer .............. SUCCESS [ 15.852 s]
    [INFO] Apache Hadoop MapReduce JobClient .................. SUCCESS [ 12.987 s]
    [INFO] Apache Hadoop Mini-Cluster ......................... SUCCESS [ 12.106 s]
    [INFO] Apache Hadoop YARN Services ........................ SUCCESS [  1.812 s]
    [INFO] Apache Hadoop YARN Services Core ................... SUCCESS [  8.685 s]
    [INFO] Apache Hadoop YARN Services API .................... SUCCESS [  9.236 s]
    [INFO] Apache Hadoop YARN Site ............................ SUCCESS [  0.859 s]
    [INFO] Apache Hadoop YARN UI .............................. SUCCESS [  0.840 s]
    [INFO] Apache Hadoop YARN Project ......................... SUCCESS [ 34.971 s]
    [INFO] Apache Hadoop MapReduce HistoryServer Plugins ...... SUCCESS [  7.376 s]
    [INFO] Apache Hadoop MapReduce NativeTask ................. SUCCESS [02:07 min]
    [INFO] Apache Hadoop MapReduce Uploader ................... SUCCESS [  9.915 s]
    [INFO] Apache Hadoop MapReduce Examples ................... SUCCESS [ 14.651 s]
    [INFO] Apache Hadoop MapReduce ............................ SUCCESS [ 15.959 s]
    [INFO] Apache Hadoop MapReduce Streaming .................. SUCCESS [ 11.747 s]
    [INFO] Apache Hadoop Distributed Copy ..................... SUCCESS [ 16.314 s]
    [INFO] Apache Hadoop Archives ............................. SUCCESS [  7.115 s]
    [INFO] Apache Hadoop Archive Logs ......................... SUCCESS [  8.686 s]
    [INFO] Apache Hadoop Rumen ................................ SUCCESS [ 12.413 s]
    [INFO] Apache Hadoop Gridmix .............................. SUCCESS [ 10.490 s]
    [INFO] Apache Hadoop Data Join ............................ SUCCESS [  7.894 s]
    [INFO] Apache Hadoop Extras ............................... SUCCESS [  7.098 s]
    [INFO] Apache Hadoop Pipes ................................ SUCCESS [ 19.457 s]
    [INFO] Apache Hadoop OpenStack support .................... SUCCESS [ 12.452 s]
    [INFO] Apache Hadoop Amazon Web Services support .......... SUCCESS [04:55 min]
    [INFO] Apache Hadoop Kafka Library support ................ SUCCESS [ 36.248 s]
    [INFO] Apache Hadoop Azure support ........................ SUCCESS [ 43.752 s]
    [INFO] Apache Hadoop Aliyun OSS support ................... SUCCESS [ 34.905 s]
    [INFO] Apache Hadoop Client Aggregator .................... SUCCESS [ 17.099 s]
    [INFO] Apache Hadoop Scheduler Load Simulator ............. SUCCESS [ 18.819 s]
    [INFO] Apache Hadoop Resource Estimator Service ........... SUCCESS [ 29.363 s]
    [INFO] Apache Hadoop Azure Data Lake support .............. SUCCESS [ 30.145 s]
    [INFO] Apache Hadoop Image Generation Tool ................ SUCCESS [  8.970 s]
    [INFO] Apache Hadoop Tools Dist ........................... SUCCESS [ 46.265 s]
    [INFO] Apache Hadoop Tools ................................ SUCCESS [  0.883 s]
    [INFO] Apache Hadoop Client API ........................... SUCCESS [08:41 min]
    [INFO] Apache Hadoop Client Runtime ....................... SUCCESS [06:39 min]
    [INFO] Apache Hadoop Client Packaging Invariants .......... SUCCESS [  4.040 s]
    [INFO] Apache Hadoop Client Test Minicluster .............. SUCCESS [13:29 min]
    [INFO] Apache Hadoop Client Packaging Invariants for Test . SUCCESS [  1.937 s]
    [INFO] Apache Hadoop Client Packaging Integration Tests ... SUCCESS [  1.865 s]
    [INFO] Apache Hadoop Distribution ......................... SUCCESS [01:56 min]
    [INFO] Apache Hadoop Client Modules ....................... SUCCESS [  5.050 s]
    [INFO] Apache Hadoop Cloud Storage ........................ SUCCESS [  6.457 s]
    [INFO] Apache Hadoop Cloud Storage Project ................ SUCCESS [  0.829 s]
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time:  01:06 h
    [INFO] Finished at: 2019-09-03T14:14:45+08:00
    [INFO] ------------------------------------------------------------------------
    

    编译完成后的内容在hadoop-dist里面。感受一下为了编译这个玩意儿尝试了多少个版本:

    cmake-3.0.0         
    cmake-3.3.0       
    hadoop-2.7.7-src.tar.gz  
    hadoop-2.9.2-src         
    hadoop-3.1.2-src                   
    protobuf-2.5.0    
    cmake-3.1.0         
    hadoop-2.8.5-src     
    hadoop-2.9.2-src.tar.gz  
    hadoop-3.1.2-src.tar.gz  
    cmake-3.1.0.tar.gz  
    hadoop-2.7.7-src  
    hadoop-2.8.5-src.tar.gz  
    hadoop-3.1.2             
    hadoop-3.1.2.tar.gz
    

    五、启动运行hadoop

    hadoop-dist/target里面的hadoop-3.1.2.tar.gz拷贝到你要安装的位置,解压。

    # 进入bin目录,启动前先格式化HDFS系统
    cd hadoop-3.1.2/bin
    ./hdfs namenode -format
    ......
    ......
    2019-09-03 14:35:53,356 INFO namenode.NameNode: SHUTDOWN_MSG: 
    /************************************************************
    SHUTDOWN_MSG: Shutting down NameNode at raspberrypi/127.0.1.1
    ************************************************************/
    # 启动所有服务
    cd ../sbin/
    ./start-all.sh
    WARNING: Attempting to start all Apache Hadoop daemons as wangjun in 10 seconds.
    WARNING: This is not a recommended production deployment configuration.
    WARNING: Use CTRL-C to abort.
    Starting namenodes on [raspberrypi]
    Starting datanodes
    Starting secondary namenodes [raspberrypi]
    Starting resourcemanager
    Starting nodemanagers
    

    访问8088端口http://localhost:8088就可以看到hadoop的管理界面了!

    hadoop的web界面:

    # All Applications
    http://localhost:8088
    # DataNode Information
    http://localhost:9864
    # Namenode Information
    http://localhost:9870
    # node
    http://localhost:8042
    # SecondaryNamenode information
    http://localhost:9868
    

    问题1:启动时报错:

    $ ./start-all.sh 
    WARNING: Attempting to start all Apache Hadoop daemons as wangjun in 10 seconds.
    WARNING: This is not a recommended production deployment configuration.
    WARNING: Use CTRL-C to abort.
    Starting namenodes on [raspberrypi]
    raspberrypi: ERROR: JAVA_HOME is not set and could not be found.
    Starting datanodes
    localhost: ERROR: JAVA_HOME is not set and could not be found.
    Starting secondary namenodes [raspberrypi]
    raspberrypi: ERROR: JAVA_HOME is not set and could not be found.
    Starting resourcemanager
    Starting nodemanagers
    localhost: ERROR: JAVA_HOME is not set and could not be found.
    

    解决方案:

    vim ./etc/hadoop/hadoop-env.sh
    # export JAVA_HOME=
    改为具体的java安装路径,比如
    export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-armhf
    
  • 相关阅读:
    python直接赋值、浅拷贝与深拷贝的区别解析
    join shuffle
    Python工作流-Airflow
    【JAVA基础语法】(一)Arrays.asList的使用
    Java中的数组和List
    ArrayList和LinkedList区别
    Array和ArrayList区别
    iOS项目崩溃日志采集与分析
    iOS超全开源框架、项目和学习资料汇总
    iOS webView、WKWebView、AFNetworking 中的cookie存取
  • 原文地址:https://www.cnblogs.com/scuwangjun/p/11552080.html
Copyright © 2011-2022 走看看