spark-1.6.3源码---启动spark-shell调整日志级别

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Using Spark's repl log4j profile: org/apache/spark/log4j-defaults-repl.properties
To adjust logging level use sc.setLogLevel("INFO")
...

解决方案1：
按照提示执行

scala> sc.setLogLevel("INFO")

解决方案2：

cp ${SPARK_HOME}/conf/log4j.properties.template ${SPARK_HOME}/conf/log4j.properties

# log4j.properties.template中已配置相关内容，将其修改为properties后，配置自动生效
log4j.rootCategory=INFO, console

解决方案3：

# 根据Using Spark's repl log4j profile: org/apache/spark/log4j-defaults-repl.properties 提示，直接修改org/apache/spark/log4j-defaults-repl.properties

# org.apache.spark.Logging文件中有读取log4j属性文件相关程序逻辑以及输出相关提示信息