i have a problem with Hadoop mapreduce in R, and in the logs i did find this :
log4j:WARN No appenders could be found for logger (org.apache.hadoop.ipc.Server).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info
my problem is presented here with no reaction unfortunately , so after a lot of research i found that i need to tell where to find the log4j with this command :
-Dlog4j.configuration=file:path/log4j.properties
my question is WHERE , because i did this : java -Dlog4j.configuration=file:log4j.properties but in my terminal in ubuntu it shows me that i didn"t use java command correctly , nothing shows that the command workd or not , the output is like this :
usage: java [-option]class [args ...]
....
so i don't know where to type this command , any help will be apreciated . thank you
As far as I know log4j does not need a URL to its path.
Try this instead:
-Dlog4j.configuration=/home/user/log4j.properties
(Or whereever you stored the file)
Try to set up this before you start your application:
export JAVA_OPTS=-Dlog4j...
What you are trying to do is basically configuring java parameters. There are examples here on stackoverflow how to do this for other parameters, you will find more examples here: xlConnect R use of JVM memory