spark的logDebug模式设置

spark采用的是log4j输出运行日志，为了获取spark运行中的日志信息，可以在$SPARK_HOME的conf目录下，

比如输出spark.storage package的debug运行日志，设置如下：

# Set everything to be logged to the console
log4j.rootCategory=INFO, console
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{1}: %m%n


# Ignore messages below warning level from Jetty, because it's a bit verbose
log4j.logger.org.eclipse.jetty=WARN
log4j.logger.spark.storage=debug