[Spark] spark-shell 命令使用

心已赠人 2022-05-20 04:42 452阅读 0赞

# 环境： #

操作系统：CentOS7.3  
Java: jdk1.8.0\_45

Hadoop：hadoop-2.6.0-cdh5.14.0.tar.gz

1. spark-shell 使用帮助

[hadoop@hadoop01 ~]$ cd app/spark-2.2.0-bin-2.6.0-cdh5.7.0/bin
    [hadoop@hadoop01 bin]$ ./spark-shell --help
    Usage: ./bin/spark-shell [options]
    
    # 重要参数
    Options:
      --master MASTER_URL         spark://host:port, mesos://host:port, yarn, or local.
      --name NAME                 A name of your application.
      --jars JARS                 Comma-separated list of local jars to include on the driver
                                  and executor classpaths.
      --exclude-packages          Comma-separated list of groupId:artifactId, to exclude while
                                  resolving the dependencies provided in --packages to avoid
                                  dependency conflicts.
      --conf PROP=VALUE           Arbitrary Spark configuration property.
      --driver-memory MEM         Memory for driver (e.g. 1000M, 2G) (Default: 1024M).
      --executor-memory MEM       Memory per executor (e.g. 1000M, 2G) (Default: 1G).
     YARN-only:
      --driver-cores NUM          Number of cores used by the driver, only in cluster mode
                                  (Default: 1).
      --queue QUEUE_NAME          The YARN queue to submit to (Default: "default").
      --num-executors NUM         Number of executors to launch (Default: 2).
                                  If dynamic allocation is enabled, the initial number of
                                  executors will be at least NUM.      
    [hadoop@hadoop01 bin]$

注意：因为生产中一般不用standalone模式，这里我们只关注spark on yarn的用法。

2. 启动一个spark-shell（hdfs和yarn已启动）

[hadoop@hadoop01 ~]$ spark-shell --master local[2]   # 2=两个cores
    Using Spark's default log4j profile: org/apache/spark/log4j-defaults.properties
    Setting default log level to "WARN".
    To adjust logging level use sc.setLogLevel(newLevel). For SparkR, use setLogLevel(newLevel).
    18/07/12 22:30:58 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
    18/07/12 22:31:05 WARN ObjectStore: Failed to get database global_temp, returning NoSuchObjectException
    Spark context Web UI available at http://10.132.37.38:4040
    Spark context available as 'sc' (master = local[2], app id = local-1531405859803).    # spark-shell启动时创建的一个spark context
    Spark session available as 'spark'.
    Welcome to
          ____              __
         / __/__  ___ _____/ /__
        _\ \/ _ \/ _ `/ __/  '_/
       /___/ .__/\_,_/_/ /_/\_\   version 2.2.0
          /_/
             
    Using Scala version 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_45)
    Type in expressions to have them evaluated.
    Type :help for more information.
    
    scala>

说明：

1) local\[x\] 中x代表使用主机上的x个cores；

2) spark-shell启动时创建了一个spark context：'sc' (master = local\[2\], app id = local-1531405859803)。一个spark-shell就是一个spark应用程序，一个spark应用程序必然有一个spark context；

重要：正因为启动spark-shell时候自动创建了别名叫sc的这个spark context，我们再创建自己的SparkContext不会有效，这一点官网有明确说明；

3) 如果spark-shell需要引用一些其他的jar包（比如mysql jdbc），可以通过--jars 引用它；或者将jar包的路径添加到classpath；

4) 如果要使用maven依赖，使用参数 --packages "org.example:example:0.1"，其中引号里面的内容即为maven 的dependency的g:a:v；

5) spark-shell启动时会启动一个Spark 的Web UI。由于刚刚启动spark-shell的时候并没有指定appName，所以Web UI右上角显示Spark shell application UI（源码$SPARK\_HOME/bin/spark-shell里面定义）。如果指定了AppName，则这里显示AppName。

Spark Web UI默认使用端口号4040，如果4040被占用，它会自动+1，即使用4041；若4041也被占用，依此类推。

![70][]

Spark Environment里面也是一样的道理

![70 1][]

注意：这里有一个参数java.io.tmpdir，生产中必须要调优！

![70 2][]

Environment下面的Classpath Entries 这里会把$HADOOP\_HOME/conf/ 和$HADOOP\_HOME/jars/下面的包全部都导进来。

![70 3][]

6) spark-shell 底层也是调用spark-submit进行作业的提交的（源码查看： $SPARK\_HOME/bin/spark-shell）

其他的诸如spark-sql、sparkR等底层也都是由spark-submit来进行作业提交的。

[hadoop@hadoop01 ~]$ vi $SPARK_HOME/bin/spark-shell    # 搜索submit
    function main() {
      if $cygwin; then
        # Workaround for issue involving JLine and Cygwin
        # (see http://sourceforge.net/p/jline/bugs/40/).
        # If you're using the Mintty terminal emulator in Cygwin, may need to set the
        # "Backspace sends ^H" setting in "Keys" section of the Mintty options
        # (see https://github.com/sbt/sbt/issues/562).
        stty -icanon min 1 -echo > /dev/null 2>&1
        export SPARK_SUBMIT_OPTS="$SPARK_SUBMIT_OPTS -Djline.terminal=unix"
        "${SPARK_HOME}"/bin/spark-submit --class org.apache.spark.repl.Main --name "Spark shell" "$@"
        stty icanon echo > /dev/null 2>&1
      else
        export SPARK_SUBMIT_OPTS
        "${SPARK_HOME}"/bin/spark-submit --class org.apache.spark.repl.Main --name "Spark shell" "$@"
      fi
    }

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[70]: /images/20220520/1756a65d11c44a3a8e834b58fb9cab48.png
[70 1]: /images/20220520/ee56cfda368c48cb893f848a2b88ae72.png
[70 2]: /images/20220520/6229e5c332984c4bbddb443fd014ce22.png
[70 3]: /images/20220520/57d8d604c195435b85cf34d3d100ad21.png